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23rd Annual Katzenstein Distinguished Lecture Series4:00pm
11/8
23rd Annual Katzenstein Distinguished Lecture Series
Friday, November 8th, 2019
04:00 PM - 05:00 PM
Storrs Campus Student Union Theater
Professor Dame Jocelyn Bell Burnell from the University of Oxford in England is world famous for her discovery of pulsars in 1967. At the time of the discovery of pulsars, Bell Burnell was a graduate student at the University of Cambridge and worked with her supervisor, Anthony Hewish. This discovery is considered one of the most important achievements of the 20th century and was recognized by a Nobel Prize in Physics in 1974, awarded to her supervisor Anthony Hewish as well as to astronomer Martin Ryle.
In 2018, she also received the Breakthrough Prize in Fundamental Physics. Bell Burnell donated her full $3 million Breakthrough prize to fund "women, underrepresented ethnic minority, and refugee students to become physics researchers." She told http://space.com, "I feel that I made my contribution in part because I felt an outsider," she added. "I was one of very few women, and I wasn't from the southeast of England, the affluent part of the country. So, I think increasing diversity of the workforce actually allows all sorts of things to develop."
Professor Dame Bell Burnell has a highly distinguished career including serving as the head of the Royal Astronomical Society, the first female president of both the Institute of Physics and The Royal Society of Edinburgh. For services to astronomy she was appointed Dame Commander of the Order of the British Empire by Her Majesty Queen Elizabeth II in 2007.
View the livestream at: https://www.youtube.com/TheUCTVchannel14 -
Prof. Meredith Hughes, Wesleyan, "Using Debris Disks to Trace the Dynamics of Planetary Systems", Physics Colloquium (Prof. Meredith Hughes, Wesleyan)3:30pm
11/1
Prof. Meredith Hughes, Wesleyan, "Using Debris Disks to Trace the Dynamics of Planetary Systems", Physics Colloquium (Prof. Meredith Hughes, Wesleyan)
Friday, November 1st, 2019
03:30 PM - 04:30 PM
Storrs Campus BPB 131
Prof. Meredith Hughes, Wesleyan
Using Debris Disks to Trace the Dynamics of Planetary Systems
Debris disks are signposts of mature planetary systems, and millimeter-size dust is an excellent tracer of the gravitational landscape around planets. I will describe observations using the Atacama Large Millimeter/Submillimeter Array (ALMA) that leverage the presence of debris disks to explore the dynamics of planetary systems. For example, we can use the vertical puffiness (or lack thereof) to hunt for otherwise invisible Uranus and Neptune analogs, and in systems with directly imaged companions we can use the chaotic zone extent as a measurement of the dynamical mass of the companion. We are also using millimeter disk morphology as a test of theories of the origin of wide-separation planets.
Cookies will be served prior to the talk, at 3:00 p.m. outside BPB-131 -
Prof. C. Battersby, Department of Physics, University of Connecticut, "The Milky Way Laboratory", Graduate Student Seminar12:15pm
11/1
Prof. C. Battersby, Department of Physics, University of Connecticut, "The Milky Way Laboratory", Graduate Student Seminar
Friday, November 1st, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. C. Battersby, Department of Physics, University of Connecticut
The Milky Way Laboratory
Our own Milky Way Galaxy is a powerful and relatively nearby laboratory in which to study the physical processes that occur throughout the Universe. From the organization of gas on galactic scales to the life cycle of gas and stars under varied environmental conditions, studies of our Milky Way underpin many areas of modern astrophysics. I will present a brief tour of our Milky Way Laboratory, including 1) the connection between long, filamentary molecular clouds and spiral structure, and 2) how observing our extreme, turbulent Galactic Center (the Central Molecular Zone) can help us learn more about how gas is converted into stars during the peak epoch of cosmic star formation. I will also briefly discuss the Origins Space Telescope, a NASA mission concept study for the 2020 Decadal survey, opening up about 3 orders of magnitude of discovery space on science from first stars to life.
Nuclear Astrophysics -
H. Perry Hatchfield, Department of Physics, University of Connecticut, "Understanding Enigmatic Star Formation Activity in the Milky Way's Galactic Center", Astronomy Seminar2:30pm
10/30
H. Perry Hatchfield, Department of Physics, University of Connecticut, "Understanding Enigmatic Star Formation Activity in the Milky Way's Galactic Center", Astronomy Seminar
Wednesday, October 30th, 2019
02:30 PM - 03:00 PM
Storrs Campus GS-119
H. Perry Hatchfield, Department of Physics, University of Connecticut
Understanding Enigmatic Star Formation Activity in the Milky Way's Galactic Center
The CMZoom Survey, a Submillimeter Array (SMA) large program, has produced a catalog of dense objects in the 1.3mm dust continuum, complete within all high (\(>10^{23}\) N(H2)) column density clouds across the inner 300 pc of the Milky Way. This region, known as the Central Molecular Zone (CMZ) is well studied for its extreme densities, pressures, temperatures and turbulent forces relative to the Galactic disk, as well as a mysterious deficiency of star formation relative to its dense molecular gas content. To understand this deficiency, we are building a suite of hydrodynamic simulations with a consistent dynamical model for the CMZ, implemented with variable physics. By developing these simulations and observations together, we aim to compile a set of tools to better understand the relationship between dense gas and star formation across galactic environments. -
Gloria Fonseca Alvarez, Department of Physics, University of Connecticut, "The Sloan Digital Sky Survey Reverberation Mapping Project Radius Luminosity Relation", Astronomy Seminar2:00pm
10/30
Gloria Fonseca Alvarez, Department of Physics, University of Connecticut, "The Sloan Digital Sky Survey Reverberation Mapping Project Radius Luminosity Relation", Astronomy Seminar
Wednesday, October 30th, 2019
02:00 PM - 02:30 PM
Storrs Campus GS-119
Gloria Fonseca Alvarez, Department of Physics, University of Connecticut
The Sloan Digital Sky Survey Reverberation Mapping Project Radius Luminosity Relation
Results from a few decades of reverberation mapping (RM) studies have revealed a correlation between the radius of the broad-line emitting region and the continuum luminosity of active galactic nuclei. This "radius-luminosity" relation allows us to estimate black-hole masses across cosmic time, using single-epoch spectroscopy rather than long-term RM monitoring.
I will discuss results from the Sloan Digital Sky Survey Reverberation Mapping project that differ significantly from the previously established radius-luminosity relation, introducing new challenges for single-epoch black hole masses. -
Dr. Leonid Glazman, Department of Physics, Yale University, "Topology of the Fermi surface wave functions and magnetic oscillations in metals", Condensed Matter Physics Seminar2:00pm
10/29
Dr. Leonid Glazman, Department of Physics, Yale University, "Topology of the Fermi surface wave functions and magnetic oscillations in metals", Condensed Matter Physics Seminar
Tuesday, October 29th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS 119
Dr. Leonid Glazman,
Department of Physics, Yale University
Topology of the Fermi surface wave functions and magnetic oscillations in metals
In the traditional Fermiology, the size and shape of the Fermi surface in a metal is often deduced from the period of magnetic oscillations of transport or thermodynamic characteristics, e.g., from the de Haas -- van Alphen effect. We find that the intercept g of the infinite-field asymptote of the oscillations yields information about the topology of the Fermi surface wave functions. The topological invariance of g originates from the symmetry of extremal orbits, which depends not only on the space group but also on the field orientation with respect to the crystal axes. The wave functions fall into 10 distinct classes stemming from the crystalline symmetry; transitions between the classes occur via magnetic breakdown. -
Prof. Chunlei Guo, Department of Physics and Astronomy, University of Rochester, "Material Functionalization with Femtosecond Lasers", Physics Colloquium (Prof. Chunlei Guo, University of Rochester)3:30pm
10/25
Prof. Chunlei Guo, Department of Physics and Astronomy, University of Rochester, "Material Functionalization with Femtosecond Lasers", Physics Colloquium (Prof. Chunlei Guo, University of Rochester)
Friday, October 25th, 2019
03:30 PM - 04:30 PM
Storrs Campus BPB-131
Prof. Chunlei Guo, Department of Physics and Astronomy, University of Rochester
Material Functionalization with Femtosecond Lasers
Femtosecond lasers are a powerful tool for high-precision material processing and functionalization. In this talk, I will discuss some of our recent advancements in femtosecond laser micro- and nano-processing, including the resulting surface structures, their formation dynamics, the drastically altered surface functionalities, and demonstration of various applications. I will also discuss the broader research activities in my labs, including extreme nonlinear optics, advanced material development, nanophotonics, and ultrafast metrology.
Cookies will be served prior to the talk, at 3:00PM outside Room BPB-131 -
Prof. M. Gai, Department of Physics, University of Connecticut, "Nuclear Astrophysics", Graduate Student Seminar12:15pm
10/25
Prof. M. Gai, Department of Physics, University of Connecticut, "Nuclear Astrophysics", Graduate Student Seminar
Friday, October 25th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. M. Gai, Department of Physics, University of Connecticut
Nuclear Astrophysics
Stellar evolution and Cosmological processes (after the first three minutes) are for the most part, nuclear processes. Nuclear Astrophysics, the study of these processes, reached a level of maturity where Stars and Cosmological events can be used to study fundamental questions in Physics. We will review some of these processes as an introduction to Nuclear Astrophysics, where stars have been used to study neutrino properties and deviation from the standard model. I will review a few of these questions that were studied at the Laboratory for Nuclear Science (LNS) at Avery Point together with an emphasis on open questions that are now being addressed at the LNS. -
Dr. C. Vargas, Department of Astronomy and Steward Observatory, University of Arizona, "Disk-halo interaction in nearby galaxies -- New SFRs and the bright (but low surface brightness) future of UV space astronomy", Astronomy Seminar2:00pm
10/23
Dr. C. Vargas, Department of Astronomy and Steward Observatory, University of Arizona, "Disk-halo interaction in nearby galaxies -- New SFRs and the bright (but low surface brightness) future of UV space astronomy", Astronomy Seminar
Wednesday, October 23rd, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. C. Vargas, Department of Astronomy and Steward Observatory, University of Arizona
Disk-halo interaction in nearby galaxies -- New SFRs and the bright (but low surface brightness) future of UV space astronomy
I present current efforts and future ultraviolet (UV) space missions aimed at determining the nature of disk-halo interactions and star formation in the nearby universe. I discuss new narrow-band H-alpha imaging for 24 nearby edge-on galaxies in the Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES). I use the images in conjunction with the Wide-field Infrared Survey Explorer 22 micron imaging of the sample to estimate improved star formation rates (SFRs) using the updated recipe from Vargas et al. (2018). I will discuss new observational evidence for the use of a mid-IR extinction correction applied to SFR calibrations when used in edge-on or extremely dusty galaxies. The revised SFR estimates produce a newly-measured correlation between SFR and radio scale height, and further relationships between star formation and radio halo properties are explored. I identify a region of star formation located at extreme distance from the disk of NGC 4157, possibly ionized by a single O5.5 V star.
In the second part of this talk, I will discuss future UV space mission concepts currently being developed at the University of Arizona. The Hyperion Small Explorer mission (P.I., E. Hamden) will directly measure molecular hydrogen through its fluorescent line transitions in the UV. The main goals of Hyperion are to understand the behavior of molecular clouds at their surfaces, test cloud lifecycle theories, and understand the impact of cloud surface conditions on their interiors. Lastly, I will discuss a SmallSat concept (P.I., C. Vargas) that will map the elusive coronal gas phase in nearby galaxy halos via the O VI transition in the Far-UV. Both of these missions are enabled by major recent advancements in UV coatings and detector technology. -
Prof. P. Mannheim and Prof. J. Trump , Physics Colloquium (The 2019 Nobel Prize in Physics)3:30pm
10/18
Prof. P. Mannheim and Prof. J. Trump , Physics Colloquium (The 2019 Nobel Prize in Physics)
Friday, October 18th, 2019
03:30 PM - 04:30 PM
Storrs Campus BPB-131
Prof. P. Mannheim and
Prof. J. Trump
The 2019 Nobel Prize in Physics
The 2019 Nobel Prize in physics was awarded to James Peebles for cosmology, and to Michel Mayor and Didier Queloz for the discovery of exoplanets. This colloquium will describe their work. -
Prof. A. Puckett, Department of Physics, University of Connecticut, "Sub-femtoscale structure of strongly interacting matter from "hard" electron-nucleus collisions", Graduate Student Seminar12:15pm
10/18
Prof. A. Puckett, Department of Physics, University of Connecticut, "Sub-femtoscale structure of strongly interacting matter from "hard" electron-nucleus collisions", Graduate Student Seminar
Friday, October 18th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. A. Puckett, Department of Physics, University of Connecticut
Sub-femtoscale structure of strongly interacting matter from "hard" electron-nucleus collisions
The emergence of nucleon structure and dynamics from strong interactions among its elementary quark and gluon constituents is one of the most difficult and interesting problems in all of physics. The strong interaction, NOT the electroweak Higgs mechanism, is responsible for the dynamical generation of the mass of approximately 98% of all ordinary matter in the universe. Scattering of ultrarelativistic electron beams from nucleon and nuclear targets is the tool of choice for the precision study of nucleon structure.
The Super BigBite Spectrometer (SBS) at Jefferson Lab, a novel device currently nearing completion, with installation and first beam tentatively scheduled for 2020, will facilitate a focused program of high-impact nucleon structure measurements in electron-nucleon scattering at large momentum transfer. In this talk I will give an overview of the SBS program and opportunities for graduate student involvement. -
Dr. V. Juričić, Nordic Institute for Theoretical Physics, "Higher order topological states: General principle of construction and their realizations", Condensed Matter Physics Seminar2:00pm
10/17
Dr. V. Juričić, Nordic Institute for Theoretical Physics, "Higher order topological states: General principle of construction and their realizations", Condensed Matter Physics Seminar
Thursday, October 17th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. V. Juričić,
Nordic Institute for Theoretical Physics
Higher order topological states: General principle of construction and their realizations
Topological gapless edge or surface states are protected by the bulk topological invariant and arise as a consequence of the so-called bulk-boundary correspondence, which is a hallmark feature of a topological state. Recently, the notion of topological states of matter has been extended to the so-called higher order topological (HOT) states featuring gapless surface states at boundaries of co-dimension higher than one, such as hinges and corners.
In this talk, I will particularly discuss a general principle of construction for these states within the Dirac Hamiltonian framework [1]. As I will show, if a D-dimensional first-order or regular topological phase involves m Hermitian matrices that anticommute with additional p−1 mutually anticommuting matrices, it is conceivable to realize an nth-order HOT phase, where n=1,...,p, with appropriate combinations of discrete symmetry-breaking Wilsonian masses. This principle will be illustrated on prototypical three-dimensional gapless systems, such as a nodal-loop semimetal possessing SU(2) spin-rotational symmetry, and Dirac semimetals, transforming under (pseudo)spin- 1/2 or 1 representations. The former system permits an unprecedented realization of a fourth-order phase, without any surface zero modes. The crystalline symmetries play an important for HOT states, but, as I will show, they can also be realized in amorphous solids [2]. Particularly, as long as structural disorder is confined by the outer crystalline boundary, the system continues to host corner states, realizing an amorphous HOT insulator. However, as structural disorder percolates to the edges, corner states start to dissolve into amorphous bulk, and ultimately the system becomes a trivial insulator. Finally, I will discuss a realization of an out-of-equilibrium second order topological insulator, which is obtained from a quantum spin Hall insulator by using a rather generic kicking protocol involving a mass that breaks time-reversal and fourfold rotational symmetries [3].
1. D. Calugaru, V. Juričić, and B. Roy, Phys. Rev. B 99, 041301(R) (2019).
2. A. Agarwala, V. Juričić, and B. Roy, B., arXiv:1902.00507.
3. T. Nag, V. Juričić, and B. Roy, arXiv:1904.07247. -
Dr. Jian-Xin Zhu, Los Alamos National Laboratory, "Electronic Structure and Topology in f-Electron Quantum Matter", Condensed Matter Physics Seminar2:00pm
10/15
Dr. Jian-Xin Zhu, Los Alamos National Laboratory, "Electronic Structure and Topology in f-Electron Quantum Matter", Condensed Matter Physics Seminar
Tuesday, October 15th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. Jian-Xin Zhu, Los Alamos National Laboratory
Electronic Structure and Topology in f-Electron Quantum Matter
In recent years there has been a surge of interest in quantum materials with topologically protected properties, which are robust against disorder effects. Interesting examples are topological insulators and three-dimensional Weyl metals. Electronic structure has played an important role in the exotic properties of these materials. In this talk, I will present our recent theoretical study of electronic structure and its topology in f-electron PuB\({}_4\) [1] and Ce\({}_3\)(Pt,Pd)\({}_3\)Bi\({}_4\) [2] compounds. In addition to uncovering topologically nontrivial electronic states, the role of f-electron and in particular the electronic correlation effects are discussed in the framework of density functional theory and its combination with the dynamical mean-field theory.
[1] H. Choi, W. Zhu, S.K. Cary, L.E. Winter, Z. Huang, R.D. McDonald, V. Mocko, B.L. Scott, P.H. Tobash, J.D. Thompson, S.A. Kozimor, E.D. Bauer, J.-X. Zhu, and F. Ronning, "Experimental and theoretical study of topology and electronic correlations in PuB\({}_4\)", Phys. Rev. B 97, 201114(R) (2018).
[2] C. Cao, G.-X. Zhi, and J.-X. Zhu, "From Trivial Kondo Insulator Ce\({}_3\)Pt\({}_3\)Bi\({}_4\) to Topological Nodal-line Semimetal Ce\({}_3\)Pd\({}_3\)Bi\({}_4\)", arXiv:1904.00675. -
Dr. Masakaki Tomii, Department of Physics, University of Connecticut Non-perturbative matching of Wilson coefficients from four-flavor to three-flavor theories using lattice QCD, Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
10/14
Dr. Masakaki Tomii, Department of Physics, University of Connecticut Non-perturbative matching of Wilson coefficients from four-flavor to three-flavor theories using lattice QCD, Particle, Astrophysics, and Nuclear Physics Seminar
Monday, October 14th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-413.E
Dr. Masakaki Tomii, Department of Physics, University of Connecticut
Non-perturbative matching of Wilson coefficients from four-flavor to three-flavor theories using lattice QCD
The first lattice result for direct CP violation in \(K \to \pi\pi\) decay in the Standard Model published by RBC/UKQCD in 2015 is desired to be more precise to see the deviation from the experimental value more clearly. In this talk, I will overview RBC/UKQCD's calculation of \(K \to \pi\pi\) matrix elements mentioning a particular error
source: Since RBC/UKQCD calculated the matrix elements with the four-quark operators without the charm quark, we need the
corresponding Wilson coefficients in the three-flavor theory, which can be obtained by converting from the four-flavor theory.
Perturbative matching may result in a significant uncertainty since it
needs to be done below charm threshold. To resolve this problem, we are trying to do this matching in a non-perturbative prescription using lattice QCD. I will explain the strategy of the matching and show some results of an exploratory calculation. -
Dr. Jianwei Qiu, Director, Theory Center, Jefferson Lab, "Nuclear Femtography - A new frontier of science and technology", Physics Colloquium3:30pm
10/11
Dr. Jianwei Qiu, Director, Theory Center, Jefferson Lab, "Nuclear Femtography - A new frontier of science and technology", Physics Colloquium
Friday, October 11th, 2019
03:30 PM - 04:30 PM
Storrs Campus BPB 131
Dr. Jianwei Qiu, Director, Theory Center, Jefferson Lab
Nuclear Femtography - A new frontier of science and technology
The proton and neutron, known as nucleons, are the fundamental building blocks of all atomic nuclei and make up essentially all the visible matter in the universe, including the stars, the planets, and us. Nucleons are not static but have complex internal structure, emerged as strongly interacting and relativistic bound states of quarks and gluons of Quantum Chromodynamics. Both theory and experimental technology have now reached a point where human is capable of exploring the inner structure of nucleons and nuclei at a sub-femtometer without breaking them, which is expected to lead to a new emerging science of nuclear femtography. In this talk, I will demonstrate that as exciting as the nano-science and technology has been for recent years, there must be a quantum transition when we enter the era of femto-science and technology. The newly upgraded CEBAF facility at Jefferson Lab and proposed Electron-Ion Collider to be built in the US will be a pair of complementary and much needed facilities for exploring the nuclear femtography. They are the most powerful tomographic scanners and/or microscopes able to precisely image inner structure of nucleon and nuclei with a sub-femtometer resolution to help address the most compelling unanswered questions about the elementary building blocks of the visible world, and are capable of taking us to the next frontier of the Standard Model of physics. -
Prof. George N. Gibson, High-Intensity Laser Physics Group, Department of Physics, University of Connecticut, "Exploring Extreme Nonlinear Physics and Quantum Molecular Dynamics with High-Intensity Laser Pulses", Graduate Student Seminar12:15pm
10/11
Prof. George N. Gibson, High-Intensity Laser Physics Group, Department of Physics, University of Connecticut, "Exploring Extreme Nonlinear Physics and Quantum Molecular Dynamics with High-Intensity Laser Pulses", Graduate Student Seminar
Friday, October 11th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. George N. Gibson, High-Intensity Laser Physics Group, Department of Physics, University of Connecticut
Exploring Extreme Nonlinear Physics and Quantum Molecular Dynamics with High-Intensity Laser Pulses
Ultrafast laser systems can now produce ultrashort (attosecond) pulses of light with extremely high intensity (\(10^{22}\) W/\(cm^2\)), as recognized by the 2018 Nobel Prize in Physics. This has opened up a new world in nonlinear physics and may even test the nonlinear polarizability of the vacuum, itself. More immediate applications may include direct imaging of molecular orbitals and ultrafast atomic scale dynamics. -
Philip Engelke, Department of Physics and Astronomy, Johns Hopkins University, "OH as an Alternate Tracer for Molecular Gas", Astronomy Seminar2:00pm
10/9
Philip Engelke, Department of Physics and Astronomy, Johns Hopkins University, "OH as an Alternate Tracer for Molecular Gas", Astronomy Seminar
Wednesday, October 9th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Philip Engelke,
Department of Physics and Astronomy, Johns Hopkins University
OH as an Alternate Tracer for Molecular Gas
While molecular gas is an important component of the baryonic mass content of galaxies, tracing interstellar molecular H2 gas is complicated by the fact that diffuse, cold H2 is not detectable. In order to study the mass and distribution of molecular gas in galaxies, tracers such as CO are typically used as surrogates. Evidence suggests large reservoirs of undetected "CO-dark" molecular gas. In this work, we explore the use of OH 18 cm transition as an alternate tracer for molecular gas, by performing observational surveys with the Green Bank Telescope. OH appears to be a viable tracer, and reveals molecular gas in places where CO has not been detected. This finding indicates a larger extent and mass of molecular gas in the Galaxy, translating to roughly twice the known mass of H2. I will describe our results for a "blind survey", as well as a study of the W5 star-forming region in comparison to quiescent interstellar regions, and modeling of the volume density in these different regions. We find that CO-dark molecular gas is widespread and predominantly located outside of star-forming regions, the more typical targets of astronomical observation, and occurs in regions of lower volume density gas. I also describe a technique making use of measured differences in OH main line excitation temperatures and modeling to probe physical conditions of molecular gas. -
Dr. Seok-Woo Lee, Materials Science and Engineering, University of Connecticut, "Superelasticity of ThCr2Si2-Structured Intermetallic Compounds at the Micrometer Scale", Condensed Matter Physics Seminar2:00pm
10/8
Dr. Seok-Woo Lee, Materials Science and Engineering, University of Connecticut, "Superelasticity of ThCr2Si2-Structured Intermetallic Compounds at the Micrometer Scale", Condensed Matter Physics Seminar
Tuesday, October 8th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. Seok-Woo Lee, Materials Science and Engineering, University of Connecticut
Superelasticity of ThCr2Si2-Structured Intermetallic Compounds at the Micrometer Scale
The work represents a report of the discovery of superelasticity in ThCr2Si2-structured novel intermetallic compound (CaFe2As2) and its hybrid structure (CaKFe4As4) under "uni-axial" compression at the micrometer scale and discusses the strong possibility of deformation-induced superconductivity switching. They exhibit unprecedentedly large elastic limit (10~17%), ultrahigh strength (3~5 GPa), and repeatable cyclic loading response through the reversible lattice collapse caused by making and breaking atomic bonds.1-4 This unique superelasticity mechanism produces a modulus of resilience orders of magnitude higher than that of most engineering materials and enables strain engineering, which refers to the modification of material properties through elastic strain. Our experimental and computational results strongly suggest that superconductivity in a high temperature superconductor, CaKFe4As4, could be turned on/off reliably through this superelasticity process, before fracture occurs, even under "uniaxial" compression. Please note that it is extremely rare to see deformation-induced superconductivity switching under uni-axial deformation, which is the preferred loading mode in engineering applications. Note that our result is only one manifestation of a wider class of such transitions found in over 2500 different ThCr2Si2-structured intermetallic compounds. If we consider their hybrid structure, there could be a much larger number of similar intermetallic compounds. Therefore, our observation can be extended to search for a large group of superelastic and strain-engineerable functional materials, and, more broadly, will lead to various research opportunities in materials science, solid-state physics, superconducting device engineering, and machine-learning-based materials research.
1. J.T. Sypek, C.R. Weinberger, S. Vijayan, M. Aindow, P.C. Canfield, S.-W. Lee, Scripta Mater. 141 10 (2017)
2. J.T. Sypek, H. Yu, K.J. Dusoe, G. Drachuck, H. Petal, A.M. Giroux, A.I. Goldman, A. Kreyssig, P.C. Canfield, S.L. Bud'ko, C.R. Weinberger, S.-W. Lee, Nature Comm. 8 1083 (2017)
3. I.N. Bakst, J.T. Sypek, S.-W. Lee, J.R. Neilson, C.R. Weinberger, -- Comp. Mater. Sci. 150, 86 (2018)
4. I.N. Bakst, K.J. Dusoe, G. Drachuk, J.R. Neilson, P.C. Canfield, S.-W. Lee, C.R. Weinberger, Acta Mater. 160 224 (2018) -
Dr. George C. Privon, Department of Astronomy, University of Florida, "Gas as a Tracer and Driver of Galaxy Evolution", Physics Colloquium3:30pm
10/4
Dr. George C. Privon, Department of Astronomy, University of Florida, "Gas as a Tracer and Driver of Galaxy Evolution", Physics Colloquium
Friday, October 4th, 2019
03:30 PM - 04:30 PM
Storrs Campus BPB 131
Dr. George C. Privon,
Department of Astronomy,
University of Florida
Gas as a Tracer and Driver of Galaxy Evolution
Nearby galaxies exhibit a diverse range of properties, from low-metallicity star-forming dwarfs through the merger-triggered compact starbursts in ultraluminous infrared galaxies. This provides a variety of laboratories to probe the physics of star formation across a wide range of physical conditions. Molecular and atomic interstellar medium (ISM) tracers probe the conditions of star forming gas as well as the impact star formation has on its surroundings. Understanding the physical drivers of emission from these ISM tracers is thus critical to understanding the physics of star formation. I will discuss our understanding of so called "dense gas" tracers in starburst galaxies and how these can probe the physical conditions of star formation. I will also describe an optical integral field spectroscopy program on dwarf galaxy pairs aimed at understanding how hierarchical formation drives star formation in low-metallicity, high gas fraction systems. Finally, I will describe ongoing efforts to leverage detailed galaxy evolution simulations to make direct comparisons with observations; applications include interpretation of ISM tracers as well as age-dating galaxy mergers and constraining their dynamical evolution. These studies provide new insights into the interpretation of molecular gas tracers and signs of intriguing behavior in merger-driven starbursts within high gas fraction galaxies.
Cookies will be served prior to the talk, at 3:00 p.m. in Room Gant South 117 -
Prof. Jonathan Trump, Department of Physics, University of Connecticut, "Multi-Messenger Echoes of Supermassive Black Holes", Graduate Student Seminar12:15pm
10/4
Prof. Jonathan Trump, Department of Physics, University of Connecticut, "Multi-Messenger Echoes of Supermassive Black Holes", Graduate Student Seminar
Friday, October 4th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. Jonathan Trump, Department of Physics, University of Connecticut
Multi-Messenger Echoes of Supermassive Black Holes
Our new era of gravitational wave astrophysics has opened an entirely new frontier for understanding black holes, from their birth in the early Universe to the supermassive monsters observed in all massive galaxies today. I will demonstrate how a new generation of industrial-scale time-domain surveys is creating a new multi-messenger view of supermassive black holes. The pioneering new SDSS-RM project uses light echoes to map the three fundamental quantities that describe astrophysical black holes: mass, spin, and growth rate. In the next decade, the new SDSS-V Black Hole Mapper and Large Synoptic Survey Telescope will map millions of supermassive black holes in light echoes, complementing the gravitational echoes seen soon in pulsar timing and (eventually) LISA. I will also discuss how Hubble Space Telescope spectroscopy can spatially resolve the fossil record of black hole seeds, as well as off-nuclear black holes leftover from recent galaxy mergers. Very soon, the first James Webb Space Telescope observations in the CEERS project will directly map the formation of the first black hole seeds in the early Universe. The next generation of multi-messenger experiments make it a truly bright time for understanding the dark nature of black hole astrophysics. -
Prof. Michael Lublinsky, Department of Physics, Ben-Gurion University, "Transport from the Fluid/Gravity Correspondence", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
10/2
Prof. Michael Lublinsky, Department of Physics, Ben-Gurion University, "Transport from the Fluid/Gravity Correspondence", Particle, Astrophysics, and Nuclear Physics Seminar
Wednesday, October 2nd, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-413.E
Prof. Michael Lublinsky, Department of Physics, Ben-Gurion University
Transport from the Fluid/Gravity Correspondence
I will first review the ideas behind all order causal relativistic hydrodynamics. Then, such hydrodynamics will demonstrated to emerge from the AdS/CFT. Finally, I will talk about chiral anomaly induced transport. -
C. Trallero-Giner, Latin-American Center of Physics, Rio de Janeiro, Brazil, "Latin American Center for Physics, a challenge for the developing of science", Physics Colloquium3:30pm
9/27
C. Trallero-Giner, Latin-American Center of Physics, Rio de Janeiro, Brazil, "Latin American Center for Physics, a challenge for the developing of science", Physics Colloquium
Friday, September 27th, 2019
03:30 PM - 04:30 PM
Storrs Campus BPB-131
C. Trallero-Giner, Latin-American Center of Physics, Rio de Janeiro, Brazil
Latin American Center for Physics, a challenge for the developing of science
Latin American Center for Physic (CLAF) has the unique status among other Latin American institutions of being an intergovernmental organization. There is no such thing for mathematics, chemistry or other discipline. The representatives at CLAF are in fact representatives of the country member states. Due to its official status, it represents an opportunity to find a way for the developing of sciences in Latin America region.
Latin American cultural history and its link with the scientific development is presented. The present talk presents an analysis of the development of science and technology in the region and the new paradigms that such Center has to face. The fields highly developed in the region are also presented and discussed.
The contributions of the organism, its distinctive feature, the different types of graduate staff training and links with various bodies that keeps the CLAF currently listed. The projection center programs to Latin America and Central America are presented emphasizing support for experimental research and technological development. The search of joint scientific policies among various similar bodies to CLAF is important for achieving new paradigms
that allow more rapid development of science and technology in Latin America.
Please join us for the Fall Ice Cream Social hosted by the Physics Graduate Student Association (PGSA) at 1:30PM in GS117 -
Prof. V. Cormier, Department of Physics, University of Connecticut, "Scattered Elastic Waves Reveal Small-scale Planetary Structure", Graduate Student Seminar12:15pm
9/27
Prof. V. Cormier, Department of Physics, University of Connecticut, "Scattered Elastic Waves Reveal Small-scale Planetary Structure", Graduate Student Seminar
Friday, September 27th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. V. Cormier, Department of Physics, University of Connecticut
Scattered Elastic Waves Reveal Small-scale Planetary Structure
Planetary structures on the order of a wavelength (1-10 km) of the elastic waves radiated by earthquakes have observable and predictable effects on recorded seismograms expressed as energy scattered into different directions and time windows. I will describe two applications that exploit observations of the scattered seismic wavefield to determine the heterogeneity spectrum of Earth's deep interior. Small-scale structures in Earth's mantle affects the coherence of seismic body waves recorded by surface arrays of seismometers through focusing, defocusing, and scattering. In one application, we are extending theories of forward wave scattering to invert the amplitude and travel time coherence of seismic waves to reveal the solid-solid phase changes predicted for the lattices of silicate minerals composing Earth's mantle. In another application, we use a radiative transport theory to show how the heterogeneity spectrum and variations in the thickness of Earth's crust can affect the amplitude of S body waves trapped in a crustal waveguide. These crust-trapped S waves are better excited by earthquakes than explosions; hence are useful for nuclear test monitoring, but are sometimes blocked by crustal thickness variations. -
Dr. Jacqueline McCleary, NASA Jet Propulsion Laboratory, Pasadena, CA, "Dark Matter and Galactic Dust at Megaparsec Scales", Astronomy Seminar2:00pm
9/25
Dr. Jacqueline McCleary, NASA Jet Propulsion Laboratory, Pasadena, CA, "Dark Matter and Galactic Dust at Megaparsec Scales", Astronomy Seminar
Wednesday, September 25th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. Jacqueline McCleary, NASA Jet Propulsion Laboratory, Pasadena, CA
Dark Matter and Galactic Dust at Megaparsec Scales
Though it comprises 80% of gravitationally interacting matter, the exact nature of dark matter is still unknown. As the largest virialized objects in the universe, clusters of galaxies lie at the nexus of cosmology and astrophysics and make excellent test beds for theories of dark matter. In this talk, I will discuss our survey of substructures in the dark matter of massive, nearby, clusters of galaxies. We reconstruct these clusters' mass distributions through their weak gravitational lensing signal, the small but coherent distortion they induce on the shapes of galaxies in their backgrounds.
Cluster cosmology studies like our own require accurate galaxy colors, and in this context I will also present evidence for an anomalous, extended, halo of dust around galaxies. By correlating the reddening of light from background galaxies with the locations of foreground objects, we find evidence of dust extending out to 10 Mpc. This potentially major systematic error is not currently accounted for in cluster cosmology studies. -
Prof. D. McCarron, Department of Physics, University of Connecticut, Graduate Student Seminar12:15pm
9/20
Prof. D. McCarron, Department of Physics, University of Connecticut, Graduate Student Seminar
Friday, September 20th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. D. McCarron, Department of Physics, University of Connecticut
Laser-cooled molecules for quantum science and ultracold chemistry
Molecular laser cooling and trapping offers a general technique to produce ultracold molecules and is applicable to a variety of species with different internal structures. This generality is well-suited to the growing list of proposed applications for ultracold molecules, from time-resolved quantum simulations to ultracold organic chemistry. However, current limitations prevent the detection and manipulation of the necessary molecule-molecule interactions in laser-cooled samples. The key barrier is inefficient trap loading, which limits the densities achieved in molecular magneto-optical traps. Here we describe two complementary experiments designed to remove this barrier and realize large, dense samples of ultracold molecules. The first targets polar molecules with closed electronic shells, such as AlCl, which have strong optical transitions ideal for trap loading and weak transitions for laser cooling towards 1 μK. The second targets light, chemically relevant species with blue optical transitions such as CH and CN. These species can give access to increased optical forces and short slowing distances thanks to their high recoil velocities. We will discuss the advantages and challenges associated with laser cooling these new species and present an update on our experimental progress. -
Dr. Michael Mattern,Max Planck Institute for Radio Astronomy, Germany, "Massive filamentary clouds and their role in star formation", Astronomy Seminar2:00pm
9/18
Dr. Michael Mattern,Max Planck Institute for Radio Astronomy, Germany, "Massive filamentary clouds and their role in star formation", Astronomy Seminar
Wednesday, September 18th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. Michael Mattern,Max Planck Institute for Radio Astronomy, Germany
Massive filamentary clouds and their role in star formation
Filamentary structures are ubiquitous in the interstellar medium of the Milky Way. They are observed within star-forming and quiescent molecular clouds and representing molecular clouds themselves. Therefore, filamentary structures play an important role in the early phases of star formation. Filaments in nearby (<500pc) molecular clouds were found to be thermally stable against gravitational collapse, fragmenting into star-forming clumps. However, the evolution of filaments with masses above the thermally critical value is unknown.
Here, I will present the analyzes of the kinematics of 283 filamentary molecular cloud candidates in the Galactic Plane using the 13CO(2--1) and C18O(2--1) data of the SEDIGISM (Structure, Excitation, and Dynamics of the Inner Galactic Inter Stellar Medium) survey. To do so, we developed an automated algorithm to derive size, mass, and kinematic properties towards all candidates. We find two-third of the filament candidates are coherent structures. Also, we find a correlation between the mass per unit length and the velocity dispersion of the filament.
Further, I present the fragmentation characteristics and kinematics of the extremely long, massive Nessie filament. The fragmentation characteristics are derived from a combined near- and mid-infrared dust extinction map, and then compared with predictions from gravitational fragmentation models. We find that the characteristics of the fragments at all scales are similar to the predictions of one model. The kinematics provided by the SEDIGISM survey reveal Nessie as a single physical object, despite several morphological differences along the filament. -
Prof. P. Mannheim, Department of Physics, University of Connecticut, "Quantum mechanics off the beaten track", Graduate Student Seminar12:15pm
9/13
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Prof. P. Mannheim, Department of Physics, University of Connecticut, "Quantum mechanics off the beaten track", Graduate Student Seminar
Friday, September 13th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. P. Mannheim, Department of Physics, University of Connecticut
Quantum mechanics off the beaten track
We discuss some non-conventional options for quantum theory. We show that
it is not always possible to write the momentum operator as the familiar derivative operator \(-id/dx\) where x is real, and discuss what one should then do. We show that basis states do not need to be normalizable to be complete, and even if normalizable do not have to obey the standard Dirac
completeness relation \(\sum |n> Prof. B. Spivak, Department of Physics, University of Washington, " Anomalous metals", Condensed Matter Physics Seminar2:00pm
9/10
Prof. B. Spivak, Department of Physics, University of Washington, " Anomalous metals", Condensed Matter Physics Seminar
Tuesday, September 10th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Prof. B. Spivak, Department of Physics, University of Washington
Anomalous metals
The observation of metallic ground states in a variety of two-dimensional electronic systems poses a fundamental challenge for the theory of electron fluids. I will analyze evidence for the existence of a regime, which we call the "anomalous metal regime," in diverse 2D superconducting systems driven through a quantum superconductor to metal transition by tuning physical parameters such as the magnetic field, the gate voltage in the case of systems with a MOSFET geometry, or the degree of disorder. The principal phenomenological observation is that in the anomalous metal, as a function of decreasing temperature, the resistivity first drops as if the system were approaching a superconducting ground state, but then saturates at low temperatures to a value that can be orders of magnitude smaller than the Drude value. The anomalous metal also shows a giant positive magneto-resistance. This behavior is observed in a broad range of parameters. I will exhibit, by theoretical solution of a model of superconducting grains embedded in a metallic matrix, that as a matter of principle such anomalous metallic behavior can occur in the neighborhood of a quantum superconductor-metal transition. However, I will also argue that the robustness and ubiquitous nature of the observed phenomena are difficult to reconcile with any existing theoretical treatment and speculate about the character of a more fundamental theoretical framework. Prof. N. Berrah, Department of Physics, University of Connecticut, "Towards Making Molecular Movies", Graduate Student Seminar12:15pm
9/6
Prof. N. Berrah, Department of Physics, University of Connecticut, "Towards Making Molecular Movies", Graduate Student Seminar
Friday, September 6th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. N. Berrah, Department of Physics, University of Connecticut
Towards Making Molecular Movies
In the past decade, improved laser technology from the Infrared to the X-ray regime has allowed scientists to advance the frontiers of time-resolved ultrafast science. Table-top ultrafast lasers as well as Free Electron Lasers (FELs) science have been identified as one of the highest priority for funding agencies.
We have pursued photo-induced molecular dynamics research with complementary table-top as
well as XUV and X-ray FELs with the ultimate goal of making molecular movies. These movies
follow the electronic and nuclear dynamics induced by the absorption of photons by molecules that occur because of the coupling between the electronic and nuclear motion in the molecules. This coupling first leads to attosecond electron excitation within the molecules, followed by nuclear motion in the femtosecond range, eventually resulting in the formation and breaking of chemical bonds on the picosecond timescale. Research highlights will be presented. Dr. Molly Gallagher, Department of Physics,University of Connecticut, "Mapping Extragalactic Dense Molecular Gas: Ties to Environment and Star Formation ", Astronomy Seminar2:00pm
9/4
Dr. Molly Gallagher, Department of Physics,University of Connecticut, "Mapping Extragalactic Dense Molecular Gas: Ties to Environment and Star Formation ", Astronomy Seminar
Wednesday, September 4th, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. Molly Gallagher, Department of Physics,University of Connecticut
Mapping Extragalactic Dense Molecular Gas: Ties to Environment and Star Formation
Gas density plays an important role in galactic evolution via its connection to star formation. Yet because dense gas is difficult to observe, we are only beginning to explore how interstellar gas density and its relationship to the star formation rate depend on galactic environment. We will explore how gas density, star formation rate, and galactic environment interact on scales ranging from Galactic scale down to the scale of individual molecular clouds. This work relies on new dense gas observations of nearby spiral galaxies from the Atacama Large Millimeter/submillimeter Array (ALMA). Prof. V. Kharchenko, Department of Physics, University of Connecticut, "Non-equilibrium Processes in Atomic Science, Astrophysics, and Biology", Graduate Student Seminar12:15pm
8/30
Prof. V. Kharchenko, Department of Physics, University of Connecticut, "Non-equilibrium Processes in Atomic Science, Astrophysics, and Biology", Graduate Student Seminar
Friday, August 30th, 2019
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. V. Kharchenko, Department of Physics, University of Connecticut
Non-equilibrium Processes in Atomic Science, Astrophysics, and Biology
Non-equilibrium processes arise in transitions between different steady /equilibrium states. Experimental and theoretical investigations of these processes are most formidable tasks for researches in various scientific disciplines, including quantum mechanics, plasma physics, astrophysics, climate change, and biology. Examples of theoretical analysis of non-equilibrium processes in atomic physics, astrophysics, and biology will be discussed and current research projects will be described.
Dr. Jan M Rost, Max Planck Institute for the Physics of Complex Systems, Dresden, Germany, Atomic, Molecular, and Optical Physics Seminar2:00pm
8/21
Dr. Jan M Rost, Max Planck Institute for the Physics of Complex Systems, Dresden, Germany, Atomic, Molecular, and Optical Physics Seminar
Wednesday, August 21st, 2019
02:00 PM - 03:00 PM
Storrs Campus GS-119
Dr. Jan M Rost,
Max Planck Institute for the Physics of Complex Systems,
Dresden, Germany
Sculpting electron dynamics through its environment
Interfacing an electron with a well-controlled environment can generate unusual dynamics, in particular if the electron is easily polarizable. The Rydberg Composite, a highly excited Rydberg electron whose spatial density encompasses many atoms or molecules on sites of a designed spatial lattice is one example. We will show that a 2D Composite with a two-dimensional lattice in form of an atomic monolayer has a particularly reach electron spectrum which features energy bands and exhibits regular as well as chaotic features depending on the ratio of lattice spacing and the wavelength of the Rydberg wave function. Possibilities for experimental realizations in the ultracold will be discussed.
The second part of the talk concerns noisy photo electron spectra as generated, e.g., by short and intense SASE free electron laser pulses. Learning the corresponding electron dynamics with a deep neural network by introducing synthetic Hamilton matrices, we can purify the spectrum as if it would have been created with a normal Gaussian pulse. Perspectives of this novel way to construct ultrafast electron dynamics from given noisy spectra will be discussed. Prof. Keith Horne, University of St. Andrews, "Echo Tomography of Black Hole Accretion Flows in Active Galactic Nuclei", Special Astronomy Seminar2:00pm
7/26
Prof. Keith Horne, University of St. Andrews, "Echo Tomography of Black Hole Accretion Flows in Active Galactic Nuclei", Special Astronomy Seminar
Friday, July 26th, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West P121
Prof. Keith Horne,
University of St. Andrews
Echo Tomography of Black Hole Accretion Flows in Active Galactic Nuclei
Echo Tomography uses light travel time delays to resolve micro-arcsecond structure of black hole accretion flows in active galactic nuclei. I will discuss methods used to map the temperature-radius profile of black hole accretion discs, and to construct velocity-delay maps that probe the geometry, kinematics and ionisation structure of the associated broad emission-line regions. In particular, I will present results from the 2014 STORM campaign using HST, Swift, and ground-based telescopes to monitor spectral variations in the Seyfert galaxy NGC 5548. I will discuss anomalous behaviour observed during the campaign, and present a determination of the inclination and temperature-radius profile of its accretion disc and velocity-delay maps exhibiting evidence for an inclined Keplerian flow extending from 2 to 20 light days. Tilting the inner disc to align with black hole spin may help to address several features we are seeing in the reverberation mapping studies.
Dissertation Defense, Niraj Ghimire- Density Matrix Renormalization Group studies of interacting dipoles in a zigzag chain- Ph. D. defense11:00am
6/26
Dissertation Defense, Niraj Ghimire- Density Matrix Renormalization Group studies of interacting dipoles in a zigzag chain- Ph. D. defense
Wednesday, June 26th, 2019
11:00 AM - 01:00 PM
Storrs Campus Gant West Room 103-A
Dissertation Defense
Niraj Ghimire
Physics Department
University of Connecticut
"Density Matrix Renormalization Group studies of interacting dipoles in a zigzag chain"
The goal of my research is to simulate quantum mechanics, which is known to be a very challenging problem even for the most advanced supercomputers of today. The system I have chosen consists of molecular dipoles in a quasi-one-dimensional optical lattice. For the first part of the talk, I will discuss the situation where the dipoles are polarized in the plane of the lattice at half-filling and double occupancy is not allowed on any lattice sites. The dipoles can hop around between sites and the interactions between them can be attractive or repulsive, with the hopping and interaction allowed up to second neighbors. I am particularly interested in the zero-temperature quantum phases induced by geometrical frustration, a situation where not all the interactions are satisfied. By mapping the dipoles in this lattice to a spin-1/2 model and by using the numerical approximation method known as density matrix renormalization group (DMRG), I have studied this system and produced a complex phase diagram.
For the second part of the talk, I will discuss the situation where a dipole is trapped in each lattice site such that the dipole moment vector can be oriented in any direction. The dipoles interact with one another via dipole-dipole potential and also interact with the external field, but they do not hop around between lattice sites. I will talk about some results for this classical model. Then I will explain how I have mapped it to a spin-2 model (which is quantum mechanical) and explain some results obtained using DMRG.
Major Advisor: Dr. Susanne Yelin
Wednesday, June 26, 2019
11:00 AM
Gant Science Complex
GW-103A Dr. Ryan C. Hickox, Department of Physics and Astronomy, Dartmouth College, "Black Holes Near and Far: Environments and Evolution of Active Galactic Nuclei ", Sigma Pi Sigma Colloquium4:00pm
5/3
Dr. Ryan C. Hickox, Department of Physics and Astronomy, Dartmouth College, "Black Holes Near and Far: Environments and Evolution of Active Galactic Nuclei ", Sigma Pi Sigma Colloquium
Friday, May 3rd, 2019
04:00 PM - 05:00 PM
Storrs Campus GW-38
Dr. Ryan C. Hickox,
Department of Physics and Astronomy, Dartmouth College
Black Holes Near and Far: Environments and Evolution of Active Galactic Nuclei
Supermassive black holes (SMBHs) are ubiquitous in the centers of galaxies, and astronomers have now spectacularly obtained the first image of one in the nearby galaxy M87. Yet SMBHs are not just fascinating objects in their own right; they also have a key role to play in the cosmic evolution of their host galaxies and large-scale structures, as they grow and radiate energy in the form of active galactic nuclei (AGN). I will give an overview of recent breakthroughs in our understanding of AGN, exploring the smallest scales around the SMBH to the huge surrounding dark matter halos, and tracing the growth of SMBHs from the early Universe to the present epoch. I will conclude with a look forward at exciting prospects in AGN science with upcoming and proposed future observatories.
Coffee will be served prior to the talk, at 3:00 p.m., In Room GW-103 Dr. Jim Zickefoose, Senior Research Scientist, Mirion Technologies, "Applying a physics degree to positions in industry", Graduate Student Seminar12:15pm
5/3
Dr. Jim Zickefoose, Senior Research Scientist, Mirion Technologies, "Applying a physics degree to positions in industry", Graduate Student Seminar
Friday, May 3rd, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Dr. Jim Zickefoose,
Senior Research Scientist, Mirion Technologies
Applying a physics degree to positions in industry
I received my PhD from the University of Connecticut 9 years ago and since that time have been working in industry as a physicist for Canberra Inc. (now Mirion Technologies). There were a number of skills I gained during my studies as a PhD student that helped me obtain my job in industry as well as progress up the technical ladder. I will briefly discuss my primary PhD research topic, experimental nuclear astrophysics, identifying some of the skills obtained during my research that are vital in industry. Mirion is involved in the detection, quantification, remediation of nuclear radiation on a number of levels, most notable in the development of High Purity Germanium (HPGe) detectors. I will provide an overview of Mirion's core interests and describe how my current and previous roles there have contributed to those interests. As is true with any sector you will choose to work in, there are benefits and drawbacks to working there. I will discuss a number of aspects that are in my opinion assets of industrial work as well as number of points of frustration that I have found in industry. Finally, I have been involved in the hiring of a number of incoming physicist personnel at Mirion. I will discuss some key points to consider when searching for, applying to, interviewing for, and accepting positions in industry. Atomic, Molecular, and Optical Physics Seminar2:15pm
5/2
Atomic, Molecular, and Optical Physics Seminar
Thursday, May 2nd, 2019
02:15 PM - 03:15 PM
Storrs Campus Physics Building, P121
Dr. Ryan Carollo,
Department of Physics and Astronomy, Bates College
Blowing Bubbles... in Space!
Bose-Einstein condensates (BECs) can be used as sensitive probes or tests of delicate physics. However, gravitational sag equivalent to 100 nanokelvin per micron can adversely affect sensitive measurements or delicate potentials. NASA and JPL have solved this problem by installing a BEC machine (the Cold Atom Laboratory - CAL) on the International Space Station. We're using it to blow bubbles - fully-connected, quasi-2-dimensional shells of weakly-trapped condensate - and study them in a shape that can't be achieved on Earth. Astronomy Seminar12:15pm
5/1
Astronomy Seminar
Wednesday, May 1st, 2019
12:15 PM - 01:15 PM
Storrs Campus Gant West P121
Dr. Erin Cox, UConn Counseling & Mental Health Services
Career Development Series
In this semester's "Career Development Series" we will have a special session focusing on Mental Health. We will have a presentation from Dr. Erin Cox. Dr. Erin Cox is the Assistant Director/Director of Outreach at UConn's Counseling & Mental Health Services (CMHS). With over nine years in university counseling, she has expertise in supporting students with a wide variety of mental health concerns that can impact academic performance. In this workshop, Dr. Cox will provide tips on managing stress, and an overview of services available at CMHS. Prof. Gerald Dunne, Department of Physics, University of Connecticut, "Resurgent Extrapolation: Squeezing Non-Perturbative Information from Perturbation Theory", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
4/29
Prof. Gerald Dunne, Department of Physics, University of Connecticut, "Resurgent Extrapolation: Squeezing Non-Perturbative Information from Perturbation Theory", Particle, Astrophysics, and Nuclear Physics Seminar
Monday, April 29th, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Prof. Gerald Dunne, Department of Physics, University of Connecticut
Resurgent Extrapolation: Squeezing Non-Perturbative Information from Perturbation Theory
Extrapolation is an important problem in physics: how to use asymptotic data in one parametric regime to learn about the behavior of a physical function in another parametric regime. For example: extending weak coupling expansions to strong coupling, or high temperature expansions to low temperature, or vice versa. I present new methods from "resurgent asymptotics" that dramatically improve standard numerical procedures for performing such an extrapolation: Borel summation, Pad'e approximants and conformal mapping. I illustrate the method with the concrete example of one of the Painlev'e equations, a class of nonlinear equations with many applications in physics. Starting solely with a finite number of asymptotic coefficients, we obtain a high precision extrapolation of the function throughout the complex plane, even across a phase transition. The precision far exceeds that of state-of-the-art numerical integration methods. Prof. Tracy Webb, Department of Physics, McGill University, "The Growth of the Most Massive Galaxies in the Highest Density Regions: Evidence for In-Situ Star Formation in Brightest Cluster Galaxies", Physics Colloquium (Prof. Tracy Webb, McGill)3:30pm
4/26
Prof. Tracy Webb, Department of Physics, McGill University, "The Growth of the Most Massive Galaxies in the Highest Density Regions: Evidence for In-Situ Star Formation in Brightest Cluster Galaxies", Physics Colloquium (Prof. Tracy Webb, McGill)
Friday, April 26th, 2019
03:30 PM - 04:30 PM
Storrs Campus GW-38
Prof. Tracy Webb, Department of Physics, McGill University
The Growth of the Most Massive Galaxies in the Highest Density Regions: Evidence for In-Situ Star Formation in Brightest Cluster Galaxies
The most massive galaxies in the local universe reside at the centres of galaxy clusters. These so-called Brightest Cluster Galaxies (BCGs) exhibit, as a class, highly uniform properties and are distinct from the general galaxy population. This suggests formation processes which are themselves distinct from those which dominate in massive galaxies outside of cluster cores. The mass growth of BCGs is likely linked to the overall physics of hierarchical structure formation on galaxy cluster scales, including the fundamental processes of gas cooling, star formation, energy feedback and galaxy mergers, at the centers of giant dark matter halos. In this talk I will present new results from the largest study of high-redshift BCGs conducted to date, drawn from the SpARCS optical/NIR cluster survey. Using archival infrared data we show the star formation rate within BCGs increases to z~2, and can add as much mass to the BCG population as the previous standard model of growth by dry mergers. At low redshifts, and in X-ray/SZ selected clusters, the rare examples of star forming BCGs appear to be fed by large-scale cooling flows. However, the first of the SpARCS systems we have studied in detail, SpARCS1049, has revealed a very different phenomenon -- a train-wreck of a galaxy merger at the center of the cluster. This is the first example of such a process in high-redshift cluster cores and may represent a new phase of BCG evolution, previously unaccounted for.
Coffee and tea will be served prior to the talk, at 3:00 p.m., In Room GW-103 Dr. Drew Chieda, ASML, "Physics Ph.D.'s in Private Sector Careers", Graduate Student Seminar12:15pm
4/26
Dr. Drew Chieda, ASML, "Physics Ph.D.'s in Private Sector Careers", Graduate Student Seminar
Friday, April 26th, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Dr. Drew Chieda, ASML
Physics Ph.D.'s in Private Sector Careers
Careers outside academia are a less common choice for Ph.D. physicists. Drew Chieda (Ph.D. 2012) took the less common path and is currently employed by ASML where he provides technical oversight into the development of semiconductor lithography tools.
This talk will be an open discussion forum where Drew will share his experiences and motivations to transition into the private sector. He will review some of what ASML does and why it's interesting work (for him), where some of his friends and former students are employed, how his Ph.D. skills fit into a commercial environment, and some interesting data from the American Institute of Physics.
Please come with questions! Dr. Sarah Wellons, CIERA Postdoctoral Fellow, Northwestern University, "Wild and Crazy Kids: Simulating Galaxy Formation in the Early Universe", Astronomy Seminar12:15pm
4/24
Dr. Sarah Wellons, CIERA Postdoctoral Fellow, Northwestern University, "Wild and Crazy Kids: Simulating Galaxy Formation in the Early Universe", Astronomy Seminar
Wednesday, April 24th, 2019
12:15 PM - 01:15 PM
Storrs Campus Gant West P121
Dr. Sarah Wellons,
CIERA Postdoctoral Fellow,
Northwestern University
Wild and Crazy Kids: Simulating Galaxy Formation in the Early Universe
As techniques have improved over the last decade, observations have peered deep into the Universe's history and begun to glimpse galaxies which formed in the first few billion years after the Big Bang. Evidence is mounting that galaxies in the early Universe appear and behave very differently from those nearby - for example, the most massive galaxies are extremely compact, and star-forming disks appear to have strange clumpy morphologies. In this talk, I will discuss galaxy formation at z > 2 from a theoretical perspective, presenting results drawn from both large-volume cosmological simulations (which allow us to compare and predict the statistical properties of galaxy populations) and high-resolution zoom-in simulations (which allow us to drill down on the physics governing individual systems). I will focus in particular on massive compact galaxies, whose varied formation and evolution present a case study on how galaxy populations evolve over time, and on massive disks, which are independently predicted by both simulation approaches to be very rapidly rotating at high redshift. The advents of JWST, LSST, and WFIRST over the next decade will provide us an unprecedented view of this dynamic and exciting time in the Universe's history. I will conclude by discussing future prospects for how high-z galaxy theory and simulation can anticipate and meet the challenges that these new observations will inevitably bring. Prof. Jordy de Vries, University of Massachusetts Amherst, "Neutrinoless double beta decay in effective field theory", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
4/22
Prof. Jordy de Vries, University of Massachusetts Amherst, "Neutrinoless double beta decay in effective field theory", Particle, Astrophysics, and Nuclear Physics Seminar
Monday, April 22nd, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Prof. Jordy de Vries, University of
Massachusetts Amherst
Neutrinoless double beta decay in effective field theory
Next-generation neutrinoless double-beta decay (0nu2beta) experiments aim to discover lepton number violation in order to shed light on the nature of neutrino masses. A non-zero signal would have profound implications by demonstrating the existence of elementary Majorana particles and possibly pointing towards a solution of matter-antimatter asymmetry in the universe. However, the interpretation of the experimental signal (or lack thereof) requires care as complicated hadronic and nuclear input is required to connect the experimental data to a fundamental description of lepton-number violation. In this talk, I use effective field theories to connect 0nu2beta measurements to the fundamental lepton-number-violating source. In particular, I will argue that interpretation in terms of a light Majorana neutrino mass is more complicated than normally considered, and a new leading contributions must be included. Women in Physics Colloquium3:30pm
4/19
Women in Physics Colloquium
Friday, April 19th, 2019
03:30 PM - 04:30 PM
Storrs Campus GW-38
Women in Physics Colloquium Prof. George Gibson, High-Intensity Laser Physics Group, Department of Physics, University of Connecticut, "Exploring EXTREME Nonlinear Physics and Quantum Molecular Dynamics with High-Intensity Laser Pulses ", Graduate Student Seminar12:15pm
4/19
Prof. George Gibson, High-Intensity Laser Physics Group, Department of Physics, University of Connecticut, "Exploring EXTREME Nonlinear Physics and Quantum Molecular Dynamics with High-Intensity Laser Pulses ", Graduate Student Seminar
Friday, April 19th, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Prof. George Gibson, High-Intensity Laser Physics Group,
Department of Physics, University of Connecticut
Exploring EXTREME Nonlinear Physics and Quantum Molecular Dynamics with High-Intensity Laser Pulses
Ultrafast laser systems can now produce ultrashort (attosecond) pulses of light with extremely high intensity (\(10^{22}\) W/cm\(^2\)), as recognized by the 2018 Nobel Prize in Physics. This has opened up a new world in nonlinear physics and may even test the nonlinear polarizability of the vacuum, itself. More immediate applications may include direct imaging of molecular orbitals and ultrafast atomic scale dynamics. Dr. Yu-Sheng Liu, Tsung-Dao Lee Institute, Shanghai , "First Principle Calculation of PDFs from LaMET", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
4/15
Dr. Yu-Sheng Liu, Tsung-Dao Lee Institute, Shanghai , "First Principle Calculation of PDFs from LaMET", Particle, Astrophysics, and Nuclear Physics Seminar
Monday, April 15th, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Dr. Yu-Sheng Liu, Tsung-Dao Lee Institute, Shanghai
First Principle Calculation of PDFs from LaMET
Parton distribution functions (PDFs) are important
quantities describing the probability densities of constituents of hadrons and serve as key inputs in high energy experiments. PDFs, with their nonperturbative nature and intrinsic Minkowski time dependence, can only obtain from phenomenological global fits for decades. A breakthrough came with the Large Momentum Effective Theory (LaMET), which allows us to extract PDFs on the lattice. In this talk, I will introduce the framework of LaMET, then give a lattice simulation example to demonstrate how it works. Edward Pollack Distinguished Lecture , Pollack Distinguished Lecture3:30pm
4/12
Edward Pollack Distinguished Lecture , Pollack Distinguished Lecture
Friday, April 12th, 2019
03:30 PM - 05:00 PM
Storrs Campus GW-38 (formerly PB-38)
Edward Pollack Distinguished Lecture
Attosecond Pulses Generated in Gases and Solids
P.B. Corkum
Joint Attosecond Science Lab
University of Ottawa and National Research Council of Canada
Abstract: Attosecond pulses are generated by electron wave packets that are extracted from a quantum system by an intense light pulse and travel through the continuum under the influence of the electric field of the light. Portions of each electron wave packet are forced to re-collide with its parent ion after the field reverses direction. Upon re-collision, the electron and ion can recombine, emitting soft X-ray radiation that can be in the form of attosecond pulses. This highly nonlinear process occurs in atoms, molecules and solids and offers unique measurement opportunities -- for measuring the attosecond pulse itself; the orbital(s) from which it emerged; and the band structure of material in which the wave packets moved.
Bio: Dr. Corkum is a fellow of the Royal Societies of Canada and London; a foreign member of the US, the Austrian and the Russian Academy of Science. In 2013, he was awarded Saudi Arabia's King Faisal Prize for science and Israel's Harvey Prize for physics. In 2014 he was named "Thompson Reuters Citation Laureate for work that is of Nobel class and likely to earn the Nobel someday". In 2018 he received the SPIE Gold medal and the IOP's Newton Medal, both societies' highest awards.
Friday, April 12, 2019
3:30 p.m.
Gant Science Complex
Physics, Room GW-38
Refreshments will be served prior to the talk at 2:30 outside of the lecture hall Prof. Menka Jain, Department of Physics, University of Connecticut, "Interests in Multiferroics and Other Functional Materials", Graduate Student Seminar12:15pm
4/12
Prof. Menka Jain, Department of Physics, University of Connecticut, "Interests in Multiferroics and Other Functional Materials", Graduate Student Seminar
Friday, April 12th, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Prof. Menka Jain,
Department of Physics, University of Connecticut
Interests in Multiferroics and Other Functional Materials
A multiferroic combines any two or more of the primary ferroic orderings (ferroelectric, ferroeleastic, ferromagnetic) in the same phase, such as the ferroelectric-ferroelastics that form the basis of piezoelectric transducers. The term "magnetoelectric multiferroics" is used for materials that combine ferroelectricity with ferromagnetism or, more loosely, with any kind of magnetism. One of the most appealing aspects of such multiferroics is their so-called magnetoelectric coupling. Even though first experimental observation of magnetoelectric multiferroicity was done in 1960s; today's renaissance of these material was enabled by a combination of theoretical and experimental factors. This includes the availability of modern synthesis techniques--particularly thin-film allowing good control over crystallinity and chemical stoichiometry in samples. In my talk, I will discuss some of the basic properties of ferroics/multiferroics and my group's research work on a few other function and multifunctional materials. Prof. Carlos Trallero, Department of Physics, University of Connecticut, "Your job most likely won't be in academia: Transferring your skills to industry", Graduate Student Seminar12:15pm
4/5
Prof. Carlos Trallero, Department of Physics, University of Connecticut, "Your job most likely won't be in academia: Transferring your skills to industry", Graduate Student Seminar
Friday, April 5th, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Prof. Carlos Trallero,
Department of Physics, University of Connecticut
Your job most likely won't be in academia: Transferring your skills to industry
Statistically Ph.D. and M.Sc. in physics are more likely to obtain a job in industry. I will present some of examples of very successful transfers to industry jobs and some of the skills that you will gain working in the lab that will help you with the transition. Prof. Ben Heidenreich, University of Massachusetts Amherst, "Quantum gravity and the swampland", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
4/1
Prof. Ben Heidenreich, University of Massachusetts Amherst, "Quantum gravity and the swampland", Particle, Astrophysics, and Nuclear Physics Seminar
Monday, April 1st, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Prof. Ben Heidenreich, University of Massachusetts Amherst
Quantum gravity and the swampland
I review the "swampland" approach to extracting testable predictions from quantum gravity, with a particular focus on the Weak Gravity Conjecture as a well developed example. Prof. Beth Parks, Department of Physics & Astronomy, Colgate University, "Air Quality Measurements in Uganda ", Physics Colloquium (Prof. Beth Parks, Colgate University)3:30pm
3/29
Prof. Beth Parks, Department of Physics & Astronomy, Colgate University, "Air Quality Measurements in Uganda ", Physics Colloquium (Prof. Beth Parks, Colgate University)
Friday, March 29th, 2019
03:30 PM - 04:30 PM
Storrs Campus GW-38
Prof. Beth Parks, Department of Physics & Astronomy, Colgate University
Air Quality Measurements in Uganda
During the 2015-16 academic year, I was a Fulbright scholar at Mbarara University of Science and Technology in Uganda, where I initiated a program to monitor PM10 concentrations in three distinct environments: an urban center (Kampala), a small city (Mbarara) and a village location (Rubindi), both in the wet season and the dry season. These measurements are still underway through the PhD project of a Ugandan student I am supervising. These concentrations were measured using co-located gravimetric (filter-based) collectors and real-time optical instruments.
The results show that particulate levels are high in all three locations, with average PM10 levels measured gravimetrically of 157 mg/m3 in Kampala; 124 mg/m3 in Mbarara; and 188 mg/m3 in Rubindi. (WHO guidelines for maximum PM10 levels are 20 mg/m3; US EPA levels are somewhat more lenient.) Ongoing work involves correlating the different measurement techniques, as well as analysing the particulates to determine the sources. Prof. Boris Sinkovic, Department of Physics, University of Connecticut, "Topological Insulators, New Paradigm for Quantum Electronics", Graduate Student Seminar12:15pm
3/29
Prof. Boris Sinkovic, Department of Physics, University of Connecticut, "Topological Insulators, New Paradigm for Quantum Electronics", Graduate Student Seminar
Friday, March 29th, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Prof. Boris Sinkovic,
Department of Physics, University of Connecticut
Topological Insulators, New Paradigm for Quantum Electronics
Recent discovery of topological insulators (TI) and realization that they present new states of matter has generated much excitement in the condensed matter physics community and beyond. TI are insulators in the bulk but their boundaries support gapless spin-chiral state with extraordinary properties and relativistic momentum dispersion. Because of the time reversal symmetry, the electrons at the boundaries cannot back-scattered by non-magnetic impurities and their spin-coherence is preserved over very long distances, which is of great technological interest in spintronics and quantum computing. In particular, magnetic TI are predicted to exhibit opening of the energy gap at the Dirac point and give rise to massive Dirac fermions, leading to the experimental realizations of quantum anomalous Hall effect (QAHE). On the other hand the superconducting TI are proposed to induce new collective particle, Majorana fermions that have a potential to be a platform for quantum computing. In this talk I will present our group's attempts to induce the magnetism and superconductivity in TI, and the challenges to overcome. The studies combine growth of atomically thin films of TI and momentum resolving spectroscopy of Dirac states by angle-resolved photoemission (ARPES) technique, performed at our UCONN lab and at the Brookhaven National Lab. The talk has been rescheduled for April 22, RESCHEDULED: Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
3/18
The talk has been rescheduled for April 22, RESCHEDULED: Particle, Astrophysics, and Nuclear Physics Seminar
Monday, March 18th, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
The talk has been rescheduled for April 22
Prof. Jordy de Vries, University of
Massachusetts Amherst
Neutrinoless double beta decay in effective field theory
Next-generation neutrinoless double-beta decay (0nu2beta) experiments aim to discover lepton number violation in order to shed light on the nature of neutrino masses. A non-zero signal would have profound implications by demonstrating the existence of elementary Majorana particles and possibly pointing towards a solution of matter-antimatter asymmetry in the universe. However, the interpretation of the experimental signal (or lack thereof) requires care as complicated hadronic and nuclear input is required to connect the experimental data to a fundamental description of lepton-number violation. In this talk, I use effective field theories to connect 0nu2beta measurements to the fundamental lepton-number-violating source. In particular, I will argue that interpretation in terms of a light Majorana neutrino mass is more complicated than normally considered, and a new leading contributions must be included. Dr. Andrew Millis, Center for Computational Quantum Physics, The Flatiron Institute and Department of Physics, Columbia University, "Meeting Dirac's Challenge: From Quantum Entanglement to Materials Theory", Charles Reynolds Distinguished Lecture3:30pm
3/15
Dr. Andrew Millis, Center for Computational Quantum Physics, The Flatiron Institute and Department of Physics, Columbia University, "Meeting Dirac's Challenge: From Quantum Entanglement to Materials Theory", Charles Reynolds Distinguished Lecture
Friday, March 15th, 2019
03:30 PM - 04:30 PM
Storrs Campus GW 38, Physics Building
Dr. Andrew Millis, Center for Computational Quantum Physics, The Flatiron Institute and Department of Physics, Columbia University
Meeting Dirac's Challenge:
From Quantum Entanglement to Materials Theory
About 90 years ago, P. A. M. Dirac established the foundations of many-body quantum mechanics. Summarizing, he wrote ``The underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known, and the difficulty is only that the exact application of these laws leads to equations much too complicated to be soluble. It therefore becomes desirable that approximate practical methods of applying quantum mechanics should be developed, which can lead to an explanation of the main features of complex atomic systems without too much computation.'' Meeting Dirac's challenge, in other words developing approximate practical methods of determining the properties of interacting many-electron systems, so as to predict e.g. which materials will be novel magnets or high transition temperature superconductors, is one of the grand challenges of modern science. Recent progress has been enabled by remarkable developments in ideas, algorithms and computational power. The interplay between theoretical materials science and research into the fundamental phenomenon of quantum mechanical entanglement, has been crucial to progress in both fields. In this talk I will give an overview of modern quantum many-body theory, outlining the difficulties, describing some recent successes, and presenting a vision for the future.
Friday, March 15, 2019
3:30 p.m.
Gant Science Complex
Physics, Room GW-38
Refreshments will be served prior to the talk at 2:30 in room GW-103 Prof. Alan Wuosmaa, Department of Physics, University of Connecticut, "The Structure of "Exotic" Nuclei", Graduate Student Seminar12:15pm
3/15
Prof. Alan Wuosmaa, Department of Physics, University of Connecticut, "The Structure of "Exotic" Nuclei", Graduate Student Seminar
Friday, March 15th, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Prof. Alan Wuosmaa, Department of Physics, University of Connecticut
The Structure of "Exotic" Nuclei
Atoms you can't dig out of the ground, and why you should care about them.
Nuclear physicists developed a basic understanding of the properties of atomic nuclei many decades ago, and that understanding has evolved to the point where the structure of stable or near-stable nuclei is reasonably well understood through a combination of modeling, theory and experiment. The theories used to explain stable and near-stable radioactive nuclei, however, are not well tested for nuclei that possess a large imbalance in the numbers of protons and neutrons that makes them behave very differently than stable nuclei. Such unstable nuclei are not typically present on Earth, however play a very significant role in violent astrophysical events that are responsible for the formation of many of the elements that are found in nature. I will describe some of the characteristics that make such nuclei "exotic," and present some new experimental methods that are being used to provide data that can help understand the properties of these systems that can be used to guide new, modern theories of nuclear structure. Dr. Adam Summers, Department of Physics, Kansas State University, "Ultrafast, Strong-Field Investigation of Nanosystems", Atomic, Molecular, and Optical Physics Seminar1:30pm
3/14
Dr. Adam Summers, Department of Physics, Kansas State University, "Ultrafast, Strong-Field Investigation of Nanosystems", Atomic, Molecular, and Optical Physics Seminar
Thursday, March 14th, 2019
01:30 PM - 02:30 PM
Storrs Campus Physics Building, P103A
Dr. Adam Summers, Department of Physics, Kansas State University
Ultrafast, Strong-Field Investigation of Nanosystems
Here I present work investigating the evolution of various nanosystems in extremely intense, ultrafast laser pulses. We study the dynamical processes initiated in these nanosystems over five order of magnitude of peak laser intensity, from 10^10 W/cm2 to 10^15 W/cm2. Specific processes include: thermal evolution and damage of nanowires under irradiation of a train of intense pulses, photoelectron reqscattering on the surface of nanoparticles, plasmonic enhancements of photoionization and the ultrafast formation of nanoplasmas from nanoparticles. Multimodal Spectroscopies of Correlated Materials" Dr Ilya Drozdov, Brookhaven National Laboratory , Condensed Matter Physics Seminar2:00pm
3/13
Multimodal Spectroscopies of Correlated Materials" Dr Ilya Drozdov, Brookhaven National Laboratory , Condensed Matter Physics Seminar
Wednesday, March 13th, 2019
02:00 PM - 03:00 PM
Storrs Campus GW103A
Multimodal Spectroscopies of Correlated Materials"
Dr Ilya Drozdov,
Brookhaven National Laboratory
In this talk Ilya will present the ongoing work, plans and past results on spectroscopy of correlated oxides. Ilya is a part of the BNL team building a unique capability mergin ARPES, local spectroscopy and MBE growth at BNL. The talk will highlight the past work and present new directions. Dr. Catherine Kealhofer, Department of Physics, Williams College, "Generating and controlling ultrafast electron pulses for time-resolved electron diffraction", Atomic, Molecular, and Optical Physics Seminar3:30pm
3/11
Dr. Catherine Kealhofer, Department of Physics, Williams College, "Generating and controlling ultrafast electron pulses for time-resolved electron diffraction", Atomic, Molecular, and Optical Physics Seminar
Monday, March 11th, 2019
03:30 PM - 04:30 PM
Storrs Campus Physics Building, P121
Dr. Catherine Kealhofer,
Department of Physics,
Williams College
Generating and controlling ultrafast electron pulses for time-resolved electron diffraction
Ultrafast electron diffraction (UED) is a powerful technique that lets us measure the positions of atoms in a crystal as they evolve during chemical and physical transformations. These measurements can give insight into how materials work on a microscopic level as well as guide the design of devices that respond on fast timescales. For some time, the best-available time resolution in UED has hovered around 100 fs (1 fs =10-15 s), just shy of the 10 fs resolution required to see the fastest atomic motions. In my talk, I'll explain how ultrafast electron diffraction works and why it's challenging to break the 100-fs resolution barrier. I'll show experimental results on a recent technique that uses terahertz electromagnetic fields to compress electron pulses in time. This technique has the potential to improve the resolution of UED below 100 fs and maybe even below ~1 fs, into the regime of electronic dynamics. The talk will also introduce ultrafast electron sources based on laser-triggered electron emission from nanometrically sharp metal tips. Not only is the physics of ultrafast electron emission in this system very rich, but the extraordinarily small source size in comparison with typical ultrafast flat photocathode sources can dramatically improve the beam quality, leading to smaller probe sizes, higher quality diffraction patterns, and enabling new techniques like ultrafast electron holography. Prof. Stephen Pate, New Mexico State University, "Exploring the Axial Structure of the Nucleon", Physics Colloquium (Professor Stephen Pate, NMSU)3:30pm
3/8
Prof. Stephen Pate, New Mexico State University, "Exploring the Axial Structure of the Nucleon", Physics Colloquium (Professor Stephen Pate, NMSU)
Friday, March 8th, 2019
03:30 PM - 04:30 PM
Storrs Campus GW-38
Prof. Stephen Pate,
New Mexico State University
Exploring the Axial Structure of the Nucleon
Modern electron-scattering facilities, such as CEBAF at Jefferson Lab and MAMI at Mainz, have made possible a deep exploration of the electric and magnetic distributions in the nucleon, via measurement of the so-called "vector form factors" accessible via elastic electron scattering experiments. Our knowledge of the "axial form factor", on the other hand, has lagged behind because this sector, related to angular momentum, is suppressed in electron scattering and is more easily explored in elastic and quasi-elastic neutrino scattering. Of particular interest is the isolation of the strange quark contribution to the nucleon axial form factor, as this is related to the strange quark contribution to the nucleon spin, a quantity which has so far resisted a definitive determination. The MicroBooNE experiment at Fermilab is uniquely suited to explore the axial form factor through both neutral-current and charge-current neutrino interactions. I'll present an overview of the general MicroBooNE physics program and an in-depth look at our current status with respect to the axial form factor determination. Prof. Robin Cote, Department of Physics, University of Connecticut, "AMO Theory at UConn: Ultracold Physics", Graduate Student Seminar12:15pm
3/8
Prof. Robin Cote, Department of Physics, University of Connecticut, "AMO Theory at UConn: Ultracold Physics", Graduate Student Seminar
Friday, March 8th, 2019
12:15 PM - 01:15 PM
Storrs Campus P121
Prof. Robin Cote, Department of Physics, University of Connecticut
AMO Theory at UConn: Ultracold Physics
Whenever a new window of parameters open up in Science, new discoveries follow. Examples range from ultrafast physics with atto-second lasers probing the time scale of electrons' motion, or the Kepler space telescope which allows the discovery of thousands of exo-planets. Another such new regime arises from ultracold temperatures, where the slow motion of particles allow to probe new behaviors, such as Bose-Einstein condensation of atoms or molecules, degenerate Fermi gases, and much more. In this presentation, I will introduce what ultracold AMO physics is, and describe the current research in my group on ultracold Rydberg physics and ultracold chemistry, and their applications to quantum information science and astrophysics. Prof. Zohreh Davoudi, University of Maryland., "Towards analog and digital quantum simulations of strongly-interacting dynamics", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
3/4
Prof. Zohreh Davoudi, University of Maryland., "Towards analog and digital quantum simulations of strongly-interacting dynamics", Particle, Astrophysics, and Nuclear Physics Seminar
Monday, March 4th, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Prof. Zohreh Davoudi, University of Maryland.
Towards analog and digital quantum simulations of strongly-interacting dynamics
According to Feynman, quantum computers will be the most suitable platforms to simulate nature. Although as of today, quantum computers with capability and reliability comparable or beyond those of classical computers do not exist, rapid progress in quantum technologies, and a vast growth in interest and resources in quantum information sciences, promise a future in which quantum computation may play an important role in addressing computationally-challenging problems in all areas of sciences and technology. Nuclear and high-energy physics are among the areas in which high-performance computing has been applied successfully to address a range of problems arising from the strong-interactions dynamics. However, our current approach has severe limitations when it comes to investigations of finite-density systems or real-time dynamics. It is believed that a quantum computational approach to such problems is superior to classical approaches, but it remains an open question how to reformulate problems accordingly to harness the quantum advantage on
near-term and future devices. This talk will report on some of the progress made in addressing this question in simple strongly-interacting models, with a focus on an ongoing work at the University of Maryland that leverages on the existing quantum hardware, in particular the ion-trap quantum simulator and quantum computer. Prof. Philip Mannheim, University of Connecticut, "Title: Is dark matter fact or fantasy -- clues from the data", Physics Colloquium (Prof. Philip Mannheim)3:30pm
3/1
Prof. Philip Mannheim, University of Connecticut, "Title: Is dark matter fact or fantasy -- clues from the data", Physics Colloquium (Prof. Philip Mannheim)
Friday, March 1st, 2019
03:30 PM - 04:30 PM
Storrs Campus GW-38
Prof. Philip Mannheim, University of Connecticut
Title: Is dark matter fact or fantasy -- clues from the data
Abstract: We discuss the arguments both in favor of and against dark matter. With the repeated failure of experiment to detect dark matter we discuss what could be done instead, and to this end look for clues in the data themselves. We identify a contribution to galactic rotation curves coming from the rest of the visible Universe, and suggest that dark matter is just an attempt to describe this global effect in terms of standard Newtonian gravity within galaxies. Dr. Vladimir Juricic, Nordic Institute for Theoretical Physics, "Interacting spin-1/2 and spin-3/2 nodal fermions: Quantum criticality and transport", Condensed Matter Physics Seminar2:30pm
3/1
Dr. Vladimir Juricic, Nordic Institute for Theoretical Physics, "Interacting spin-1/2 and spin-3/2 nodal fermions: Quantum criticality and transport", Condensed Matter Physics Seminar
Friday, March 1st, 2019
02:30 PM - 03:30 PM
Storrs Campus GW121
Dr. Vladimir Juricic,
Nordic Institute for Theoretical Physics
Interacting spin-1/2 and spin-3/2 nodal fermions: Quantum criticality and transport
Theoretical proposals and experimental realizations of the condensed matter systems, such as topological insulators, Weyl and Dirac semimetals, displaying emergent pseudorelativistic nodal quasiparticles, have triggered a surge of activity in understanding their stability against interactions and disorder. This also motivated exploration of their universal responses, such as optical conductivity.
I will first discuss the quantum critical theory of an interacting nodal Fermi liquid of quasirelativistic pseudospin-3/2 fermions featuring a noninteracting birefringent spectrum with two distinct Fermi velocities [1]. As I will show using perturbative field-theoretical renormalization group analysis, when such quasiparticles interact via either the long-range Coulomb interaction or its short range component (responsible for spontaneous symmetry breaking), in the quantum critical regime, in two dimensions, the system is, respectively, described by a marginal Fermi liquid (featuring interaction-driven log-corrections to observables) or a non-Fermi liquid of relativistic spin-1/2 fermions, and is always a marginal Fermi liquid in three dimensions. I will also discuss our conjecture that critical spin-1/2 excitations represent a superuniversal description of the entire family of interacting quasirelativistic fermions.
In the second part of the talk, I will consider the quantum transport close to a relativistic quantum critical point, separating two-dimensional massless Dirac fermions from a fully gapped insulator or superconductor. In particular, I will consider the scaling of optical conductivity in the (high-frequency) collisionless regime (ω ≫ T) [2]. Close to such a critical point, gapless fermionic and bosonic excitations are strongly coupled, which inside the critical regime leads to a universal suppression of the interband optical conductivity as well as of the Drude peak. These results are obtained by performing the leading order 1/Nf- and ϵ-expansions, where Nf counts the fermion flavor number and ϵ is the distance from the upper-critical three spatial dimensions in the problem.
[1] B. Roy, M. P. Kennett, K. Yang & V. J., PRL 121, 157602 (2018).
[2] B. Roy & V. J., PRL 121, 137601 (2018). Prof. Michael Lubell, CCNY, "Navigating the Maze. How Science and Technology Policy Shape America and the World", Physics Colloquium (Prof. Michael Lubell, CCNY)3:30pm
2/22
Prof. Michael Lubell, CCNY, "Navigating the Maze. How Science and Technology Policy Shape America and the World", Physics Colloquium (Prof. Michael Lubell, CCNY)
Friday, February 22nd, 2019
03:30 PM - 04:30 PM
Storrs Campus GW-38
Prof. Michael Lubell, CCNY
Navigating the Maze. How Science and Technology Policy Shape America and the World Dr. Elisa Chisari, Department of Physics, University of Oxford, "Cosmology with weak gravitational lensing: challenges and opportunities", Astronomy Seminar12:30pm
2/22
Dr. Elisa Chisari, Department of Physics, University of Oxford, "Cosmology with weak gravitational lensing: challenges and opportunities", Astronomy Seminar
Friday, February 22nd, 2019
12:30 PM - 01:30 PM
Storrs Campus Gant West 103B
Dr. Elisa Chisari,
Department of Physics,
University of Oxford
Cosmology with weak gravitational lensing: challenges and opportunities
68% of the energy density of the Universe today is in the form of a mysterious "dark energy" component which seems to be driving its accelerated expansion. To elucidate the nature of this component, and to assess whether it is compatible with General Relativity, a next generation of experiments is at our doorstep. These experiments use weak distortions of galaxy shapes ("gravitational lensing") as one of their main probes, and will soon reach an unprecedented high-precision regime. In such regime, accurate modeling of the large-scale structure of the Universe becomes crucial to realize the goal of obtaining unbiased constraints on the cosmological model. I will describe efforts to build and test models of the large-scale structure using a combination of analytical theory, cosmological simulations and existing observational data sets. In particular, I will demonstrate that the incidence of galaxy formation on our interpretation of gravitational lensing observables is significant. Effects such as the impact of Active Galactic Nuclei feedback on the distribution of matter, or tidal correlations between the shapes of galaxies, are starting to play a role in our efforts to constrain cosmology. At the same time, I will show that these effects can also open up new windows into the Universe. Looking ahead to the next decade, I will describe the construction of a robust software pipeline for cosmological model predictions for the Large Synoptic Survey Telescope. Alexey Onufriev, Departments of Computer Science and Physics, Virginia Tech, "The nucleosome: from structure to function through physics", Condensed Matter Physics Seminar3:30pm
2/19
Alexey Onufriev, Departments of Computer Science and Physics, Virginia Tech, "The nucleosome: from structure to function through physics", Condensed Matter Physics Seminar
Tuesday, February 19th, 2019
03:30 PM - 04:30 PM
Storrs Campus BPB131
Alexey Onufriev, Departments of Computer Science and Physics, Virginia Tech
The nucleosome: from structure to function through physics
The nucleosome, a complex of 147 base-pairs of DNA with eight histone proteins, must protect its DNA, but, at the same time, allow on-demand access to it when needed by the cell. The exact mechanism of the control remain unclear.
We consider a series of physics-based models of the nucleosome, from the highly coarse-grained cylinders model, to fully atomistic, to multi-state atomistic.
One key conclusion is that at physiological conditions the nucleosome complex is close to the phase boundary separating it from the "unwrapped" states where the DNA is more accessible. A small drop in the positive charge (e.g. through acetylation of a lysine) of the globular histone core can significantly lower the DNA affinity to the core, and thus increase DNA accessibility. The findings suggest that charge-altering post-translational modifications in the histone core might be utilized by the cell to modulate accessibility to its DNA at the nucleosome level.
The multi-state atomistic model explores virtually all possible charge-altering post translational modifications (PTMs) in the globular histone core. The model reveals a rich and nuanced picture: the effect of PTMs varies greatly depending on location, including counter-intuitive trends such as decrease of DNA accessibility for some lysine acetylations in the core. A detailed connection to transcription regulation in-vivo is made. Dr. Alexander Khaetskii Department of Physics, University at Buffalo, SUNY and Department of Physics, UConn, Condensed Matter Physics Seminar2:00pm
2/19
Dr. Alexander Khaetskii Department of Physics, University at Buffalo, SUNY and Department of Physics, UConn, Condensed Matter Physics Seminar
Tuesday, February 19th, 2019
02:00 PM - 03:00 PM
Storrs Campus GW121
Dr. Alexander Khaetskii
Department of Physics, University at Buffalo, SUNY
and Department of Physics, UConn
Giant edge spin accumulation in a symmetric quantum well with two subbands
We have studied [1] the edge spin accumulation due to an electric current in a high mobility two-dimensional electron gas formed in a symmetric quantum well with two subbands. This study is strongly motivated by the recent experiment [2] which demonstrated the spin accumulation near the edges of a symmetric two-subband GaAs structure in contrast to no effect in a single-subband configuration. The intrinsic mechanism of the spin-orbit (SO) interaction we consider arises from the coupling between two subband states of opposite parities [3].
We have explained the experimental results. We obtain, in particular, a parametrically large magnitude of the edge spin density for a two-subband well as compared to the usual single-subband structure. Following the method developed in [4], we show that the presence of a gap in the system (i.e., the energy separation between the two subband bottoms) changes drastically the picture of the edge spin accumulation. The gap value governs the effective strength of the inter-subband SO interaction which provides a controllable crossover from the regime of weak spin accumulation to the regime of strong one by varying the Fermi energy (electron density) and/or energy gap. We estimate that by changing the gap from zero up to 1-2 K, the magnitude of the effect changes by three orders of magnitude. This opens up the possibility for the design of new spintronic devices.
[1]. A. Khaetskii and J. C. Egues, Europhysics Letters 118, 57006 (2017).
[2]. F. Hernandez et al., Phys. Rev. B 88, 161305(R) (2013).
[3]. E. Bernardes et al., Phys. Rev. Lett. 99, 076603 (2007).
[4]. A. Khaetskii, Phys. Rev. B 89, 195408 (2014). Dr. Adrian Price-Whelan, Department of Astrophysical Sciences, Princeton University, "The Milky Way as a benchmark: using surveys of our Galaxy to inform fundamental astrophysics", Astronomy Seminar12:30pm
2/15
Dr. Adrian Price-Whelan, Department of Astrophysical Sciences, Princeton University, "The Milky Way as a benchmark: using surveys of our Galaxy to inform fundamental astrophysics", Astronomy Seminar
Friday, February 15th, 2019
12:30 PM - 01:30 PM
Storrs Campus Gant West 103B
Dr. Adrian Price-Whelan,
Department of Astrophysical Sciences, Princeton University
The Milky Way as a benchmark: using surveys of our Galaxy to inform fundamental astrophysics
The Milky Way is currently the only galaxy in which we can study the detailed kinematic and chemical properties of large numbers of stars. It therefore provides a unique laboratory to test predictions made by astrophysical models of dark matter and galaxy assembly. In this talk, I will focus on how the recent confluence of all-sky photometric, astrometric, and spectroscopic surveys of Milky Way stars has enabled new dynamical constraints on the nature of dark matter. However, these surveys have also presented challenges to many of the simplifying assumptions that have enabled these inferences, for example by revealing the imprints of time-dependence and disequilibrium in the kinematics of stars throughout the Galaxy. I will discuss ways in which we can generalize our dynamical models and improve our statistical inferences to make and test precise astrophysical predictions about dark matter and galaxy formation using stars in the Milky Way. Dr. Sarah Ballard, MIT Kavli Institute, "Lifetimes of Planetary Systems around Small Stars", Astronomy Seminar12:30pm
2/13
Dr. Sarah Ballard, MIT Kavli Institute, "Lifetimes of Planetary Systems around Small Stars", Astronomy Seminar
Wednesday, February 13th, 2019
12:30 PM - 01:30 PM
Storrs Campus Gant West 103B
Dr. Sarah Ballard,
MIT Kavli Institute
Lifetimes of Planetary Systems around Small Stars
The Solar System furnishes our most familiar planetary architecture: many planets, orbiting nearly coplanar to one another. However, a typical system of planets in the Milky Way orbits a much smaller M dwarf star. Small stars present a very different blueprint in key ways, compared to the conditions that nourished evolution of life on Earth. Using ensemble studies of hundreds-to-thousands of exoplanets orbiting small stars, my research program investigates the links between planet formation from disks, orbital dynamics and stability of planetary systems, and the presence and observability of their atmospheres. These processes bear upon the potential for M dwarf systems to evolve and sustain life. Studies of exoplanets with the James Webb Space Telescope comprise the clear next step toward understanding the hospitability of the Milky Way to life. Our success hinges upon leveraging the many thousands of planet discoveries in hand to determine how to use this precious and limited resource. Prof. Lee Roberts, Boston University, "Searching for Physics Beyond the Standard Model with the World's Largest Penning Trap", Physics Colloquium (Prof. Lee Roberts, Boston University)3:30pm
2/8
Prof. Lee Roberts, Boston University, "Searching for Physics Beyond the Standard Model with the World's Largest Penning Trap", Physics Colloquium (Prof. Lee Roberts, Boston University)
Friday, February 8th, 2019
03:30 PM - 04:30 PM
Storrs Campus GW-38
Prof. Lee Roberts, Boston University
Searching for Physics Beyond the Standard Model with the World's Largest Penning Trap
Measurements of the magnetic moments of the electron and muon were intertwined with the development of the "modern physics" of the 20th century. For the muon, this trend continues, perhaps pointing to New Physics beyond the Standard Model (BSM). The magnetic moment is along the spin,
For leptons, the factor g is greater than the Dirac value of 2 because of radiative corrections, so g =2(1+ a), or equivalently a = (g-2)/2, where a is the magnetic anomaly. While the value of the muon anomaly is dominated by the lowest-order Schwinger term /2≃ 0.00116⋯, it is necessary to include higher order contributions from QED, as well as contributions from the strong interaction and electroweak gauge bosons, to compare with the experimental value. The SM value now has an uncertainty of 0.3 parts per million (ppm), and the experimental value has an uncertainty of ± 0.54 ppm. The experimental value is larger than the Standard Model value by ≃ 3.7 standard deviations, which could come from new, as yet undiscovered, BSM physics. To clarify this situation, a new experiment, E989 with the total error budget of ±0.14 ppm has been mounted at Fermilab and will soon begin the second data collection period. I will review the history of what we have already learned from previous (g-2) experiments, the physics reach of 989, and will report on its present status.
Friday, February 8, 2019
3:30 P.M.
Gant Science Complex, Physics, GW-38
Coffee and tea will be served prior to the talk, at 3:00 p.m., In Room P-103 Dr. Daniel Angles-Alcazar, Center for Computational Astrophysics, Flatiron Institute, "Multi-scale physical modeling in galaxy formation and evolution", Astronomy Seminar12:30pm
2/8
Dr. Daniel Angles-Alcazar, Center for Computational Astrophysics, Flatiron Institute, "Multi-scale physical modeling in galaxy formation and evolution", Astronomy Seminar
Friday, February 8th, 2019
12:30 PM - 01:30 PM
Storrs Campus Gant West 103B
Dr. Daniel Angles-Alcazar,
Center for Computational Astrophysics, Flatiron Institute
Multi-scale physical modeling in galaxy formation and evolution
While observations across the electromagnetic spectrum are providing an increasingly detailed view of galaxy evolution across cosmic time, theoretical models face the challenge of understanding the multi-scale physical processes that connect stars and supermassive black holes to galaxies and their cosmological environment. I will show that cosmological hydrodynamic simulations are a crucial tool to interpret observations and improve our understanding of galaxy evolution, highlighting recent results on (1) the role of supernovae, stellar winds, and radiation from massive stars regulating galaxy growth, (2) the large-scale gas flows that connect galaxies and their surrounding circumgalactic medium, and (3) the co-evolution of galaxies and their central supermassive black holes. Looking forward, I will discuss the need for leveraging major advances in a variety of simulation methodologies and I will present novel techniques that will enable a more detailed understanding of the dominant physical processes operating over the full range of scales involved in galaxy evolution. Dr. Massimo Gaspari, Department of Astrophysical Sciences, Princeton University, "Raining on Galaxies and Black Holes: Unifying the Micro and Macro Properties of AGN Feeding and Feedback", Astronomy Seminar12:30pm
2/6
Dr. Massimo Gaspari, Department of Astrophysical Sciences, Princeton University, "Raining on Galaxies and Black Holes: Unifying the Micro and Macro Properties of AGN Feeding and Feedback", Astronomy Seminar
Wednesday, February 6th, 2019
12:30 PM - 01:30 PM
Storrs Campus Gant West 103B
Dr. Massimo Gaspari,
Department of Astrophysical Sciences, Princeton University
Raining on Galaxies and Black Holes: Unifying the Micro and Macro Properties of AGN Feeding and Feedback
Feeding and feedback tied to supermassive black holes (SMBHs) play central role in the cosmic evolution of galaxies, groups, and clusters of galaxies. The self-regulated active galactic nucleus (AGN) cycle is matter of intense debate. I review key results of our numerical campaign to unveil how SMBHs are tightly coupled to the multiphase gaseous halos, linking the inner gravitational radius to the large Mpc scale and vice versa. Massively parallel magnetohydrodynamic simulations show the turbulent plasma halo radiatively cools via a top-down multiphase condensation rain of warm filaments and molecular clouds. The multiphase precipitation inherits the hot halo kinematics and thermodynamics, ultimately establishing a 'cosmic weather'. In the nuclear region, the recurrent collisions between the clouds and filaments promote angular momentum cancellation and boost the SMBH accretion rate through a mechanism known as Chaotic Cold Accretion (CCA). The CCA rapid variability triggers powerful AGN outflows, which quench the macro cooling flow and star formation, while preserving the atmospheres of galaxies, groups, and clusters in global thermal equilibrium throughout cosmic time. I highlight the key imprints of AGN feedback and feeding, such as bubbles, shocks, turbulence, and condensed structures, with a critical eye toward observational concordance, including the X-ray plasma, optical filaments, and radio molecular clouds. Ben Augenbraun, Harvard University, "Laser-cooled polyatomic molecules for improved precision measurements", Atomic, Molecular, and Optical Physics Seminar2:00pm
2/5
Ben Augenbraun, Harvard University, "Laser-cooled polyatomic molecules for improved precision measurements", Atomic, Molecular, and Optical Physics Seminar
Tuesday, February 5th, 2019
02:00 PM - 03:00 PM
Storrs Campus Gant West Building, GW121
Ben Augenbraun,
Harvard University
Laser-cooled polyatomic molecules for improved precision measurements
Ultracold molecules are a promising platform for applications in myriad fields, ranging from quantum simulation and chemistry to precision tests of fundamental physics. Recent work on the direct laser cooling of molecules has brought a number of diatomic molecules to the ultracold regime. These molecules are representative of a large, diverse class of molecules amenable to laser cooling. In this talk, we will focus on how polyatomic molecules (with three or more atoms) offer qualitatively new and powerful features, and the interesting physics of laser cooling polyatomic molecules will be described. We will discuss experimental work in the Doyle group on laser cooling CaF and SrOH molecules, and introduce a new experiment aimed at laser cooling of polyatomic molecules with high sensitivity to Beyond-the-Standard-Model physics, including YbOH and YbOCH3. Dr. Shea Garrison-Kimmel, Einstein Postdoctoral Fellow, TAPIR, Caltech, "Dark matter and galaxy formation in the Local Group", Astronomy Seminar12:30pm
2/1
Dr. Shea Garrison-Kimmel, Einstein Postdoctoral Fellow, TAPIR, Caltech, "Dark matter and galaxy formation in the Local Group", Astronomy Seminar
Friday, February 1st, 2019
12:30 PM - 01:30 PM
Storrs Campus Gant West 103B
Dr. Shea Garrison-Kimmel,
Einstein Postdoctoral Fellow,
TAPIR, Caltech
Dark matter and galaxy formation in the Local Group
Simulations show that an expanding universe where luminous galaxies trace a massive underlying web of dark matter -- an unknown type of mass whose only strong interaction is via gravity -- reproduce a wide variety of large-scale observations spectacularly well. However, basic questions remain within the model, including the nature of dark matter and the small-scale physics important to galaxy formation. Our cosmic neighborhood, the Local Group (LG), is one of the best laboratories for answering these vital questions. Because the LG contains both our galaxy, the Milky Way, and a similarly-sized neighbor, Andromeda, it provides an unprecedented viewpoint on relatively high-mass galaxy evolution. Moreover, tiny and faint dwarf galaxies, which have historically presented "problems" within the model, are only observationally accessible within the LG. I demonstrate how zoom-in simulations yield insights into the formation of the Milky Way and Andromeda, and how they reveal these so-called small-scale problems that relate to the number and internal structure of dwarf galaxies in the LG. I culminate by presenting new simulations of the LG that incorporate well-motivated prescriptions for galaxy micro-physics (e.g. star formation and stellar feedback), then discuss how these micro-physics combine to successfully reproduce the dwarf galaxies around the Milky Way. However, these new simulations also highlight how the wide variety in the structure of the dwarf galaxies around Andromeda could present a new challenge to the model, pointing either to the standard model physics neglected in the simulations or new dark matter physics. Soroush Khosravi Dehaghi, Department of Physics, University of Connecticut, "Femtosecond Laser Transient Spectroscopy of Carotenoids and Carbon Nanotubes", PhD Defense2:30pm
1/23
Soroush Khosravi Dehaghi, Department of Physics, University of Connecticut, "Femtosecond Laser Transient Spectroscopy of Carotenoids and Carbon Nanotubes", PhD Defense
Wednesday, January 23rd, 2019
02:30 PM - 04:30 PM
Storrs Campus GW103A
Soroush Khosravi Dehaghi,
Department of Physics,
University of Connecticut
Femtosecond Laser Transient Spectroscopy of Carotenoids and Carbon Nanotubes
Carotenoids and semiconducting single-wall carbon nanotubes, which are both nanoscale carbon-based quantum mechanical systems, were studied using different optical spectroscopy techniques.
The lifetime of the S\(_2\) excited state of the carotenoids were estimated using a model-based lifetime analysis routine. It was found that the addition of a conjugated carbonyl group to the carotenoid has several crucial effects on the optical response due to the alteration of the delocalized conjugated \(\pi\) molecular orbital of the molecule. These effects include the shortening of the lifetimes of the excited states, the change in the decay mechanism from the S\(_2\) excited state to the S\(_1\) excited state, and the unresolved vibrational peaks in the steady-state absorption spectrum.
The decay of the E\(_{22}\) excited state of (6,5) semiconducting carbon nanotube dispersed in flavin mononucleotide with water was observed using transient grating spectroscopy. The lifetime of this excited state was estimated to be 450 ± 50 fs. A very strong single-frequency oscillatory component was observed in the transient grating decay profile. Dr. Chiara Mingarelli, Center for Computational Astrophysics, Flatiron Institute, "Probing supermassive black hole mergers with pulsar timing", Astronomy Seminar12:30pm
1/23
Dr. Chiara Mingarelli, Center for Computational Astrophysics, Flatiron Institute, "Probing supermassive black hole mergers with pulsar timing", Astronomy Seminar
Wednesday, January 23rd, 2019
12:30 PM - 01:30 PM
Storrs Campus Gant West 103B
Dr. Chiara Mingarelli,
Center for Computational Astrophysics, Flatiron Institute
Probing supermassive black hole mergers with pulsar timing
Galaxy mergers are a standard aspect of galaxy formation and evolution, and most (likely all) large galaxies contain supermassive black holes. As part of the merging process, the supermassive black holes should in-spiral together and eventually merge, generating a background of gravitational radiation in the nanohertz regime. An array of precisely timed pulsars spread across the sky can form a galactic-scale gravitational wave detector in this band. I describe the current efforts to develop and extend the pulsar timing array concept, together with recent limits which have emerged from international efforts to constrain astrophysical phenomena at the heart of supermassive black hole mergers. Electric Form Factor of the Neutron from Asymmetry Measurements, Doctoral Dissertation Oral Defense of Richard Obrecht11:00am
1/4
Electric Form Factor of the Neutron from Asymmetry Measurements, Doctoral Dissertation Oral Defense of Richard Obrecht
Friday, January 4th, 2019
11:00 AM - 12:00 PM
Storrs Campus Gant West, P-121
Electric Form Factor of the Neutron from Asymmetry Measurements
Field of Study: Physics Dr. Marko Gacesa, BAER Institute / NASA Ames Research Center, "Photoassociation of ultracold molecular ions and controlling atom-ion charge exchange using magnetic Feshbach resonances", Atomic, Molecular, and Optical Physics Seminar4:00pm
12/10
Dr. Marko Gacesa, BAER Institute / NASA Ames Research Center, "Photoassociation of ultracold molecular ions and controlling atom-ion charge exchange using magnetic Feshbach resonances", Atomic, Molecular, and Optical Physics Seminar
Monday, December 10th, 2018
04:00 PM - 05:00 PM
Storrs Campus Physics Building, P121
Dr. Marko Gacesa,
BAER Institute / NASA Ames Research Center
Photoassociation of ultracold molecular ions and controlling atom-ion charge exchange using magnetic Feshbach resonances
Feshbach resonances offer a way to control the strength and sign of particle-particle interactions in ultracold atomic and molecular gases by tuning external magnetic or electric fields. This discovery led to a number of experimental applications in ultracold AMO physics, in particular in preparation and production of dense samples of ultracold molecules. Because of their importance, Feshbach resonances have been measured and characterized in numerous of neutral diatomic mixtures. A natural generalization of studies of neutral ultracold gases includes atom-ion mixtures, which remain much less investigated than neutral systems. Atom-ion interactions are, generally, more difficult to investigate due to their long-range nature and presence of the charge. Nevertheless, the same properties also offer a window to investigate different physical regimes than the ones accessible by the neutral systems.
In this talk, I will present recent results, obtained in collaboration with the group of Prof. Robin Cote, related to using external magnetic and electric fields in controlling charge-exchange in atom-ion collisions. Specifically, I will present our theoretical investigation of magnetic Feshbach resonances and their application to controlled charge transfer in \({}^{9,10}\)Be + \({}^{9,10}\)Be+, and \({}^{40}\)Ca+\({}^{43}\)Ca+ both of which are good model systems for heavier and more complex elements. I will also present the results of first theoretical study of photoassociative formation of cold molecular ions, where we estimated the production rates of NaCa+ molecular ions from trapped cold Na+ ions and Ca atoms. This study is based on experiments conducted in the group of Prof. W. Smith at UConn. Dr. Thomas Allison, Stony Brook University, "Ultrafast extreme ultraviolet photoemission without space charge", Condensed Matter Physics Seminar2:00pm
12/4
Dr. Thomas Allison, Stony Brook University, "Ultrafast extreme ultraviolet photoemission without space charge", Condensed Matter Physics Seminar
Tuesday, December 4th, 2018
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Dr. Thomas Allison,
Stony Brook University
Ultrafast extreme ultraviolet photoemission without space charge
Time- and Angle-resolved photoelectron spectroscopy from surfaces can be used to record the dynamics of electrons and holes in condensed matter on ultrafast time scales. However, ultrafast photoemission experiments using extreme-ultraviolet (XUV) light have previously been limited by either space-charge effects, low photon flux, or limited tuning range. In this article, we describe space-charge-free XUV photoelectron spectroscopy experiments with up to 5 nA of average sample current using a tunable cavity-enhanced high-harmonic source operating at 88 MHz repetition rate. The source delivers \(> 10^{11}\) photons/s in isolated harmonics to the sample over a broad photon energy range from 18 to 37 eV with a spot size of \(58 \times 100 \mu m^2\). From photoelectron spectroscopy data, we place conservative upper limits on the XUV pulse duration and photon energy bandwidth of 93 fs and 65 meV, respectively. The high photocurrent, lack of space charge distortions of the photoelectron spectra, and excellent isolation of individual harmonic orders allow us to observe laser-induced changes to the photoelectron spectrum at the \(10^{-4}\) level in minutes of integration time, enabling time-resolved XUV photoemission experiments in a qualitatively new regime. I will discuss demonstration experiments on Au (111) and progress towards electron dynamics in molecular films. Dr. Thomas Allison Stony Brook University, Atomic, Molecular, and Optical Physics Seminar4:00pm
12/3
Dr. Thomas Allison Stony Brook University, Atomic, Molecular, and Optical Physics Seminar
Monday, December 3rd, 2018
04:00 PM - 05:00 PM
Storrs Campus Physics Building, P121
Dr. Thomas Allison
Stony Brook University
Cavity-enhanced ultrafast spectroscopy: ultrafast meets ultrasensitive
Ultrafast optical spectroscopy methods, such as transient absorption spectroscopy and 2D spectroscopy, are widely used across many disciplines. However, these techniques are typically restricted to optically thick samples, such as solids and liquid solutions. Using a frequency comb laser and optical cavities, we present a technique for performing ultrafast optical spectroscopy with high sensitivity, enabling work in dilute gas-phase molecular beams. Resonantly enhancing the probe pulses, we demonstrate transient absorption measurements with a detection limit of \(\Delta OD = 2 \times 10^{−10}\) (\(1 \times 10^{-9} / \sqrt{Hz}\)). Resonantly enhancing the pump pulses allows us to produce a high excitation fraction at a high repetition rate, so that signals can be recorded from samples with optical densities as low as \(OD ≈ 10^{−8}\), or column densities \( < 10^{10}\) molecules∕cm\(^2\). In this talk, I will discuss initial demonstration experiments, methods for cavity-enhancing multidimensional spectroscopy signals using multiple frequency combs, and progress towards widely tunable cavity-enhanced ultrafast spectrometers operating from the ultraviolet to the infrared. Jonathan Kwolek, Department of Physics, University of Connecticut, "Studying Charge Exchange in a Hybrid Ion-neutral Trap", PhD Defense1:30pm
11/30
Jonathan Kwolek, Department of Physics, University of Connecticut, "Studying Charge Exchange in a Hybrid Ion-neutral Trap", PhD Defense
Friday, November 30th, 2018
01:30 PM - 03:30 PM
Storrs Campus GW121
Jonathan Kwolek,
Department of Physics,
University of Connecticut
Studying Charge Exchange in a Hybrid Ion-neutral Trap
Interactions between neutral and ionized atoms are medium-range, and the spiraling nature of these collisions can lead to long interaction times and large cross sections. The field of ion-neutral interactions is bolstered by methods from atomic physics, which allow us to accurately control and determine the quantum-states of the reactants. Atomic physics opens the door to studying these interactions over a large range of energies, in order to observe interesting effects from the ultracold to hot temperature regimes.
The hybrid-trap enables the concentric trapping of a sample of cold atoms and ions. The dissertation discusses our exploration into the controlled reactions in the Na+Ca^+ system, including measurements of sympathetic cooling and a charge-exchange rate which changes as a function of energy and atomic state. The quantum-state distributions of Na in our magneto-optical trap is also explored, as well as its agreement and subsequent deviation based on a predictive model. The measurements of reaction rates indicate a reaction-energy threshold in two different reaction channels, which can be corroborated by theoretical investigation. Dr. Daniel Angles-Alcazar, Center for Computational Astrophysics, Flatiron Institute, "The dual role of stellar feedback regulating galaxy evolution and the growth of supermassive black holes", Astronomy Seminar2:00pm
11/28
Dr. Daniel Angles-Alcazar, Center for Computational Astrophysics, Flatiron Institute, "The dual role of stellar feedback regulating galaxy evolution and the growth of supermassive black holes", Astronomy Seminar
Wednesday, November 28th, 2018
02:00 PM - 03:00 PM
Storrs Campus Gant West 121
Dr. Daniel Angles-Alcazar,
Center for Computational Astrophysics, Flatiron Institute
The dual role of stellar feedback regulating galaxy evolution and the growth of supermassive black holes
Feedback from massive stars, including supernovae, stellar winds, and radiation, is believed to play a central role in galaxy evolution. In this talk, I will present recent progress in understanding the implications of stellar feedback using cosmological hydrodynamic simulations from the Feedback In Realistic Environments (FIRE) project. In these simulations, stellar feedback regulates star formation locally in galaxies while driving large-scale winds that connect galaxies with their surrounding circumgalactic medium. I will discuss the efficiency of winds evacuating gas from galaxies, the importance of wind re-accretion to galaxy mass assembly, and the surprising contribution of intergalactic transfer of material between galaxies via winds. Zooming into galactic nuclei, I will show that stellar feedback regulates the early growth of the central black hole in low mass galaxies by continuously evacuating the nuclear gas reservoir, which has important implications for the co-evolution of supermassive black holes and galaxies and the frequency and mass scale of massive black hole mergers. Dr. Nora Kling Department of Physics, University of Connecticut, "Ultrafast Nuclear Motion: Resolving Hydrogen Migration(s) in Time", Atomic, Molecular, and Optical Physics Seminar4:00pm
11/26
Dr. Nora Kling Department of Physics, University of Connecticut, "Ultrafast Nuclear Motion: Resolving Hydrogen Migration(s) in Time", Atomic, Molecular, and Optical Physics Seminar
Monday, November 26th, 2018
04:00 PM - 05:00 PM
Storrs Campus Physics Building, P121
Dr. Nora Kling
Department of Physics,
University of Connecticut
Ultrafast Nuclear Motion: Resolving Hydrogen Migration(s) in Time
Intramolecular hydrogen migration is a natural process that plays a crucial role in many biological, chemical, and physical phenomena, and is the object of current research efforts in fuel cells, proteomics, and combustion chemistry. Using ultrafast, intense lasers and sophisticated pump-probe ion imaging techniques, we can explore the rich dynamics of hydrogen migration reactions, including what timescale they occur on. In my talk, I will present two studies. The first study is on acetylene, a small hydrocarbon, where a hydrogen can migrate across the carbon atoms to form its vinylidene isomer [1,2]. The second study is on ethanol, a complex molecule where both single and double hydrogen migrations occur, and the timescale for each is individually determined [3]. These experimental results, in combination with state-of-the art quantum chemical trajectory calculations, give us new insight into the complex nuclear motions in complex polyatomic molecules.
[1] C. Burger et al. Faraday Discussions 194, 495 (2016).
[2] M. Kübel et al. Phys. Rev. Lett. 116, 193001 (2016).
[3] N. G. Kling et al. submitted for publication Dr. David Murphy, MIT, "Matrix Elements for Neutrinoless Double Beta Decay from Lattice QCD", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
11/26
Dr. David Murphy, MIT, "Matrix Elements for Neutrinoless Double Beta Decay from Lattice QCD", Particle, Astrophysics, and Nuclear Physics Seminar
Monday, November 26th, 2018
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Dr. David Murphy, MIT
Matrix Elements for Neutrinoless Double Beta Decay from Lattice QCD
While neutrino oscillation experiments have demonstrated that neutrinos have small, nonzero masses, much remains unknown about their properties and decay modes. One potential decay mode --- neutrinoless double beta decay (\(0 \nu \beta \beta\)) --- is a particularly interesting target of experimental searches, since its observation would imply both the violation of lepton number conservation in nature as well as the existence of at least one Majorana neutrino, in addition to giving further constraints on the neutrino masses and mixing angles. Relating experimental constraints on \(0 \nu \beta \beta\) decay rates to the neutrino masses, however, requires theoretical input in the form of non-perturbative nuclear matrix elements which remain difficult to calculate reliably. In this talk we will discuss progress towards first-principles calculations of relevant nuclear matrix elements using lattice QCD and effective field theory techniques, assuming neutrinoless double beta decay mediated by a light Majorana neutrino. Professor Nadia Fomin, University of Tennessee, "Life and Death of the Free Neutron", Physics Colloquium3:30pm
11/16
Professor Nadia Fomin, University of Tennessee, "Life and Death of the Free Neutron", Physics Colloquium
Friday, November 16th, 2018
03:30 PM - 04:30 PM
Storrs Campus PB-38
Professor Nadia Fomin, University of Tennessee
Life and Death of the Free Neutron
Modern neutron sources provide extraordinary opportunities to study a wide variety of physics topics, including the physical system of the neutron itself. One of the processes under the microscope, neutron beta decay, is an archetype for all semi-leptonic charged-current weak processes. Precise measurements of the correlation parameters in neutron beta decay as well as the neutron lifetime itself are required for tests of the Standard Model and for searches of new physics. The state of the field will be presented and a program of current and future experiments and potential impacts explored. Dr. Turgut Yilmaz, Department of Physics, University of Connecticut, "Topological insulators and their interaction with magnetic impurities and superconductors", Condensed Matter Physics Seminar2:00pm
11/13
Dr. Turgut Yilmaz, Department of Physics, University of Connecticut, "Topological insulators and their interaction with magnetic impurities and superconductors", Condensed Matter Physics Seminar
Tuesday, November 13th, 2018
02:00 PM - 03:00 PM
Storrs Campus Gant West (Physics Building), P121
Dr. Turgut Yilmaz, Department of Physics, University of Connecticut
Topological insulators and their interaction with magnetic impurities and superconductors
Topological properties of materials have recently attracted much attention in the condensed matter physics community due, in part to their possible applications in quantum electronic devices. In particular, topological insulators (TIs) that possess gapless surface states that are topologically protected and can lead to dissipationless quantum electronics. TI's surface state exhibit relativistic momentum dispersion with the Dirac point (DP) located at the time reversal invariant momenta point while the bulk bands are inverted and gapped [1]. Currently, two majority experimental efforts have concentrated on inducing the magnetic and superconducting properties in TI, which would lead to the experimental realizations of quantum anomalous Hall effect (QAHE) and Majorana fermions, respectively [2-3].
Magnetism can be induced in TIs by incorporating impurities into the bulk or on the surface of TIs. If there is a net out-of-plane magnetic moment, an energy gap opens at the DP due to broken time reversal symmetry, which would give rise to QAHE. On the other hand, the superconductivity in can be induced in TI through the proximity effect by growing TIs on the surface of a superconductor. Both, the gapped DP and the superconductivity can be probed by angle-resolve photoemission spectroscopy (ARPES). In this talk, I will present our photoemission studies on the search of broken time reversal symmetry in magnetic TIs and proximity induced superconductivity in TI/superconductor heterostructures. Also, the experimental setup to grow and study TIs at the Physics Department of the University of Connecticut will be presented.
[1] L. Fu, C. L. Kane, and E. J. Mele, Phys. Rev. Lett. 98, 106803 (2007).
[2] X.-L. Qi and S.-C. Zhang, Rev. Mod. Phys. 83, 1057 (2011).
[3] T. Yilmaz, et al., Appl. Surf. Sci. 407, 371 (2017).