NSF award to Profs. Jain and Sochnikov
Professors Jain and Sochnikov received NSF research grant entitled “New Quantum Elastocaloric Demagnetization Refrigeration for the Millikelvin Range”. A major focus of their research will be the cooling of quantum chips. For this purpose, their teams will study ‘spin liquids’, which can be harnessed to achieve millikelvin temperatures without magnetic fields. At such low temperatures, […]
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Prof. Jain is organizing International Workshop on Oxide Electronics
Associate Professor of Physics Menka Jain and the Institute of Materials Science is co-organizing a workshop-28th International Workshop on Oxide Electronics (IWOE) in Maine next month. The IWOE series has become an important venue to discuss recent advances and emerging trends in this developing field. The aim of the workshop is to provide an interdisciplinary […]
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50th anniversary of annual physics department Mt. Monadnock hike
This coming October we’ll mark the 50th anniversary of the first hike up Mt. Monadnock by the Physics Department. We plan to hike Saturday, October 8th. Because the park recommends reservations, we will make reservations for a large group. Alumni are welcome and should contact Tom Blum or Alex Kovner as soon as possible to […]
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Super BigBite Spectrometer Era Begins in Hall A at Jefferson Lab
The first two experiments using the newly constructed collection of apparatus known as the Super BigBite Spectrometer were completed from Oct. 2021-Feb. 2022 in Jefferson Lab’s Experimental Hall A. Data were collected that will determine the neutron’s magnetic form factor (GMN) in a previously unexplored regime of momentum transfer Q2 up to 13.6 (GeV/c)2 with […]
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Prof. Jonathan Trump Interviews about the James Webb Space Telescope
The James Webb Space Telescope released its first science observations on July 12 with much fanfare and excitement across the globe. UConn Physics Professor Jonathan Trump is part of the Cosmic Evolution Early Release Science collaboration that was awarded some of the first observations on the transformative new space telescope. Prof. Trump was interviewed by several local media outlets, […]
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Dr. M. Shafayat Hossain, Princeton University, "Quasi-1D topological materials", Condensed Matter Physics Seminar2:00pm
10/5
Dr. M. Shafayat Hossain, Princeton University, "Quasi-1D topological materials", Condensed Matter Physics Seminar
Wednesday, October 5th, 2022
02:00 PM - 03:00 PM
Storrs Campus GW-117
Dr. M. Shafayat Hossain,
Princeton University
Quasi-1D topological materials -
Prof. Manasse Mbonye, the University of Rwanda, "Is cosmic dynamics self-regulating?", Particle, Astrophysics, and Nuclear Physics Seminar2:00pm
10/3
Prof. Manasse Mbonye, the University of Rwanda, "Is cosmic dynamics self-regulating?", Particle, Astrophysics, and Nuclear Physics Seminar
Monday, October 3rd, 2022
02:00 PM - 03:00 PM
Storrs Campus GS-119
Prof. Manasse Mbonye, the University of Rwanda
Is cosmic dynamics self-regulating?
In this talk we discuss a cosmological model for a universe with self-regulating features. We set up the theoretical framework for the model and determine the time evolution of the scale-factor a(t). It is shown that such a universe repeatedly goes through alternate periods of (dark) matter and dark energy domination. The resulting dynamics oscillates about its-would-be ideal time-linear or coasting path, with monotonic expansion. When compared to dynamics of the observed Universe, the model recovers
the observationally-established evolutionary features of the latter, from the big bang
to the current acceleration, and farther. It suggests a universe that emerges from a
non-singular state, associated with a non-exponential acceleration and which it exits naturally with matter-energy production. The model has neither a horizon nor a
flatness problem. It reproduces the standard parameters of the observed universe, including the cosmic age \(t_0\) and the current Hubble (constant) parameter \(H_0\). The model
makes some falsifiable predictions (consistent with recent observations) and explains some standing issues such as the dimensionless age (\(H_0 t_0 \approx 1\) ) paradox. The findings
suggest cosmic dynamics may be self-regulating and predictable. (Time allowing) we
show that the universe in this scenario behaves as a time crystal. -
Prof. Moshe Gai (Physics Department Colloquium)3:30pm
9/30
Prof. Moshe Gai (Physics Department Colloquium)
Friday, September 30th, 2022
03:30 PM - 04:30 PM
Storrs Campus GW-002
"Stellar Evolution in the Light of Gamma Beams"
Moshe Gai, University of Connecticut
Stellar evolution theory is a mature science that led to the standard solar model. It allows us to use the sun as the best well understood neutrino source with an accuracy of 1%. But in this theory the C/O ratio at the end of helium burning remains elusive. It was dubbed by Willie Fowler in his 1984 Nobel speech as a problem of "paramount importance", and it remains so today. For example, Type II supernova progenitor stars with C/O less than one leave behind a black hole and for C/O greater than one a neutron star. The C/O ratio also plays an important role in the light curve of Type Ia supernova that are used today as cosmological candles leading to the discovery of "Dark Energy".
We developed a new method to approach this problem [1] using gamma-beam from the Duke FEL light source and a time projection chamber (TPC) detector, also serving as the target. We measure new data with quality that surpasses the efforts of the last four decades. For example, we resolve a nagging disagreement of measured data with unitarity.
I will present for the non-expert an introduction to stellar evolution theory [2,3,4], define the problem, and review our new method. Light source gamma-beam facilities in the USA (Duke) and constructed in the EU (ELI-NP in Romania), allow us to anticipate a solution to this four-decade problem of stellar evolution theory.
[1] Robin Smith, Moshe Gai, Sarah R. Stern, Deran K. Schweitzer, Mohammad W. Ahmed,
Nature Communications 12, 5920 (2021),https://www.nature.com/articles/s41467-021-26179-x
[2] Moshe Gai, USDOE Office of Science, News Highlight,
https://www.energy.gov/science/np/articles/oxygen-formation-light-gamma-beams
[3] Moshe Gai and Robin Smith, The Innovation Platform, 8, 208 (2021),
https://www.innovationnewsnetwork.com/shining-light-nuclear-astrophysics/15139/
[4] Hans A. Bethe and Gerald Brown, Scientific American, 252,#5, 60 (1985). -
Dr. Saikat Banerjee, Los Alamos National Laboratory, "Emergent orbital magnetization in Kitaev quantum magnets", Condensed Matter Physics Seminar2:00pm
9/28
Dr. Saikat Banerjee, Los Alamos National Laboratory, "Emergent orbital magnetization in Kitaev quantum magnets", Condensed Matter Physics Seminar
Wednesday, September 28th, 2022
02:00 PM - 03:00 PM
Storrs Campus GW-117
Dr. Saikat Banerjee, Los Alamos National Laboratory
Emergent orbital magnetization in Kitaev quantum magnets
Unambiguous identification of the Kitaev quantum spin liquid (QSL) in materials remains a huge challenge despite many encouraging signs from various measurements. To facilitate the experimental detection of the Kitaev QSL, here we propose to use remnant charge response in Mott insulators hosting QSL to identify the key signatures of QSL. We predict an emergent orbital magnetization in a Kitaev system in an external magnetic field. The direction of the orbital magnetization can be flipped by rotating the external magnetic field in the honeycomb plane. The orbital magnetization is demonstrated explicitly through a detailed microscopic analysis of the multiorbital Hubbard-Kanamori Hamiltonian and also supported by a phenomenological picture. We first derive the localized electrical loop current operator in terms of the spin degrees of freedom. Thereafter, utilizing the Majorana representation, we estimate the loop currents in the ground state of the chiral Kitaev QSL state, and obtain the consequent current textures, which are responsible for the emergent orbital magnetization. Finally, we discuss the possible experimental techniques to visualize the orbital magnetization which can be considered as the signatures of the underlying excitations.
Preprint : arXiv:2208.06887 (2022) -
Katzenstein Distinguished Physics Lecture, "Generating High-Intensity, Ultrashort Optical Pulses" , Katzenstein Distinguished Lecture Series4:00pm
9/23
Katzenstein Distinguished Physics Lecture, "Generating High-Intensity, Ultrashort Optical Pulses" , Katzenstein Distinguished Lecture Series
Friday, September 23rd, 2022
04:00 PM - 05:00 PM
Storrs Campus GW-002
Katzenstein Distinguished Physics Lecture
"Generating High-Intensity, Ultrashort Optical Pulses"
Dr. Donna Strickland
Nobel Laureate 2018
Department of Physics & Astronomy
University of Waterloo
With the invention of lasers, the intensity of a light wave was increased by orders of magnitude over what had been achieved with a light bulb or sunlight. This much higher intensity led to new phenomena being observed, such as violet light coming out when red light went into the material. After Gerard Mourou and I developed chirped pulse amplification, also known as CPA, the intensity again increased by more than a factor of 1,000 and it once again made new types of interactions possible between light and matter. We developed a laser that could deliver short pulses of light that knocked the electrons off their atoms. This new understanding of laser-matter interactions, led to the development of new machining techniques that are used in laser eye surgery or micromachining of glass used in cell phones.
Friday, September 23, 2022
4:00 p.m.
GW-002
Refreshments will be prior to the talk at 3:00 p.m. in the
Gant Science Complex Light Court
View the livestream: http://www.kaltura.com/tiny/ov4ig -
Prof. Menka Jain, Department of Physics and Institute of Materials Science, University of Connecticut, "Exploring functional and multifunction properties of thin films, composites and bulk materials", Graduate Student Seminar12:15pm
9/23
Prof. Menka Jain, Department of Physics and Institute of Materials Science, University of Connecticut, "Exploring functional and multifunction properties of thin films, composites and bulk materials", Graduate Student Seminar
Friday, September 23rd, 2022
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. Menka Jain, Department of Physics and Institute of Materials Science, University of Connecticut
Exploring functional and multifunction properties of thin films, composites and bulk materials
In this talk, first I will talk about the basic properties of ferroics and multiferroics and their applications in many devices. Ferroic materials have been grouped by the driving field that align their ordering parameters. There are four primary ferroic materials: ferroelectric, ferromagnetic, ferroelastic, and ferrotoroidic, are characterized by a wealth of intriguing physical properties. The entire class of ferroic materials has found extensive applications in consumer electronics, variety of sensors, memory devices, health care, and military applications. Second part of my talk will explain the research that we will be carrying out for our two recently funded National Science Foundation Grants. Current trends toward device miniaturization have led to an increased interest in multifunctionality and multifunctional devices where a single device component can do multiple tasks simultaneously. Multiferroic materials with coexistence of at least two ferroic order parameters have potential for such multifunctional devices. -
Dr. Patrick Wong, NORDITA, Stockholm, Sweden, "Interactions & Topology: Auxiliary Field Approach and Generalized SSH Models", Condensed Matter Physics Seminar2:00pm
9/21
Dr. Patrick Wong, NORDITA, Stockholm, Sweden, "Interactions & Topology: Auxiliary Field Approach and Generalized SSH Models", Condensed Matter Physics Seminar
Wednesday, September 21st, 2022
02:00 PM - 03:00 PM
Storrs Campus GW-117
Dr. Patrick Wong,
NORDITA, Stockholm, Sweden
Interactions & Topology: Auxiliary Field Approach and Generalized SSH Models
This talk presents a selection of projects concerning the overlap between strong electronic correlations and topological phases in quantum matter. The first section of this talk presents properties of the non-interacting topological Su-Schrieffer-Heeger (SSH) model and certain classes of generalizations. We then study the SSH model with added local Hubbard interactions and solve the system exactly in the strongly correlated regime via dynamical mean-field theory. With the addition of interactions, we find that the density of states becomes augmented with low energy power-law features.
The second section of this talk presents the development of methods for formulating non-interacting auxiliary models for strongly correlated systems. These auxiliary models are able to capture the full dynamics of the original strongly correlated model, but with only completely non-interacting degrees of freedom. This auxiliary field methodology is applied to study the Mott transition in the one-band Hubbard model. In terms of the auxiliary system, we find that the Mott transition can be understood as a topological phase transition, which manifests as the formation and dissociation of topological domain walls. Also discussed is another auxiliary mapping scheme based on a generalized Majorana decomposition of fermions. -
Dr. Varun Makhija, University of Mary Washington, "Ultrafast Molecular Frame Quantum Tomography", Atomic, Molecular, And Optical Physics Seminar3:30pm
9/19
Dr. Varun Makhija, University of Mary Washington, "Ultrafast Molecular Frame Quantum Tomography", Atomic, Molecular, And Optical Physics Seminar
Monday, September 19th, 2022
03:30 PM - 04:30 PM
Storrs Campus GS-119
Dr. Varun Makhija, University of Mary Washington
Ultrafast Molecular Frame Quantum Tomography
Molecular dynamics are typically considered in the fixed molecule approximation -- the molecule is viewed as having a time varying distribution of charge and geometries within a fixed, molecular frame (MF). Quantum mechanically, this is equivalent to the molecule being in an eigenstate of orientation angles. Such a state, however, cannot be experimentally prepared since it is an infinite superposition of total angular momentum states. Nonetheless, we can still define a density matrix in this basis, which we dub the Lab Frame Density Matrix. In this talk I will introduce this density matrix, as well as a procedure using a combination of high resolution frequency resolves photoelectron spectroscopy (PES) and ultrafast time resolved PES to measure its matrix elements. I will describe the application of this procedure to the resonantly excited ammonia molecule, in which case all relevant density matrix elements (coherences and populations) are determined in a Born-Oppenheimer basis. With the density matrix elements known the molecular frame, time varying, electronic probability density can be constructed for a molecule at any orientation. Further, the time evolving expectation value of any electronic operator can also be constructed as a function of molecular orientation. Other than imaging the molecular dynamics, determining the experimentally prepared density matrix is also a necessary ingredient for quantum control or quantum information protocols, and for studies of fundamental phenomena such as entanglement.