The passing of Dr. David Katzenstein, a friend and benefactor of the UConn Department of Physics
Dr. David Katzenstein, a friend, and benefactor of the UConn Department of Physics, passed away on January 25, 2021 due to Covid-19. David was the son of Henry Katzenstein, the first Physics Ph.D. from UConn and a major benefactor of our Department. Currently, both the annual Katzenstein Distinguished Lecture and the Katzenstein Prize for a […]
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A Signal from Beyond
UConn astrophysicist Chiara Mingarelli is part of a team of researchers who recently published data on a hint of a signal that sent ripples of excitement through the physics community. These monumental findings are the culmination of twelve and a half years of data gathered from NANOGrav — a network of pulsars across the galaxy — all in the hopes of detecting gravitational waves.
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UConn Physics alumnus Dr. Michael Wininger
UConn Physics alumnus Dr. Michael Wininger (BS, 2003) was recently featured in the professional journal O&P Almanac (Orthotics and Prosthetics). The article describes how his eclectic background, beginning with degrees from UConn, has enabled him to lead innovations in several areas of health research. Mike is currently an Assistant Clinical Professor in the Biostatistics Department […]
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UConn Researcher an Architect for Astronomical Survey Making Observations Toward a New Understanding of the Cosmos
November 2, 2020 – Elaina Hancock – UConn Communications The Sloan Digital Sky Survey’s fifth generation – a groundbreaking project to bolster our understanding of the formation and evolution of galaxies, including the Milky Way – collected its very first observations on the evening of October 23. Image: The Sloan Digital Sky Survey’s fifth generation […]
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The passing of UConn Physics Professor Emeritus, Arnold Russek
Arnold Russek, a theoretical atomic physicist, born July 13, 1926, in New York, passed away on October 13th, 2020, in Colorado. As a young man of 18, he served honorably as a radio engineer in the Pacific during WWII. He earned his Ph.D. at the Courant Institute at New York University in 1953, and taught […]
[Read More]Recent Events
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Dr. Antonio Picón, Departamento de Química, Facultad de Ciencias, Universidad Autónoma de Madrid, "Mapping the real-time movies of chemical bonds", Atomic, Molecular, And Optical Physics Seminar4:00pm
3/3
Dr. Antonio Picón, Departamento de Química, Facultad de Ciencias, Universidad Autónoma de Madrid, "Mapping the real-time movies of chemical bonds", Atomic, Molecular, And Optical Physics Seminar
Wednesday, March 3rd, 2021
04:00 PM - 05:00 PM
Storrs Campus online
Dr. Antonio Picón, Departamento de Química, Facultad de Ciencias, Universidad Autónoma de Madrid
Mapping the real-time movies of chemical bonds
Valence electrons play a crucial role in the formation of chemical bonds within a molecular system and determine its charge and electron transfer properties. In the static regime, these properties are defined by the electron density distribution of the equilibrium geometry. However, when out of equilibrium, ultrafast electronic rearrangements within the order of a few femtoseconds together a significant alteration of the chemical bonds can occur. I will address in this talk our undergoing investigations for mapping these ultrafast changes through X-ray photoelectron spectroscopy that have been critical in retransforming the well-established concepts of chemical shifts. I will additionally illustrate our developments for the selective manipulation of chemical bonding through X-ray free electron laser pulses. -
Dr. Siddharth Mohite, UW-Milwaukee and CCA, Flatiron Institute, "Investigating Populations across the Gravitational-Wave Mass Spectrum: Statistical Tools and Implications for Astrophysics", Astronomy Seminar11:30am
3/3
Dr. Siddharth Mohite, UW-Milwaukee and CCA, Flatiron Institute, "Investigating Populations across the Gravitational-Wave Mass Spectrum: Statistical Tools and Implications for Astrophysics", Astronomy Seminar
Wednesday, March 3rd, 2021
11:30 AM - 12:00 PM
Storrs Campus online
Dr. Siddharth Mohite, UW-Milwaukee and CCA, Flatiron Institute
Investigating Populations across the Gravitational-Wave Mass Spectrum: Statistical Tools and Implications for Astrophysics
Merging compact object binaries comprising of pairs of black holes, neutron stars or a neutron star and a black hole are energetic sources of gravitational-wave (GW) and electromagnetic (EM) radiation. Current and future gravitational-wave observatories such as LIGO-Virgo-KAGRA, LISA and NANOGrav will help uncover a diverse population of these binaries across the mass spectrum. While the LIGO-Virgo-KAGRA observatories probe compact objects roughly from 1 to 100 times a solar mass, observatories such as LISA and NANOGrav are predicted to probe supermassive binaries in the million to billion solar mass regimes. On the other hand, telescopes around the world will aid in detecting binaries that contain neutron stars by observing an associated electromagnetic counterpart called a kilonova. Investigating the properties of these binary populations will shed light on some long-standing problems in astrophysics such as stellar and galaxy evolution and nuclear equation of state. In this talk, I will present an attempt to create a Bayesian framework that can simultaneously use information from GW and EM surveys to place constraints on the kilonova population. I will also briefly introduce a method to model the mass distribution of binaries detectable by LIGO-Virgo-KAGRA, using Gaussian processes. Finally, I will also present some investigations into modeling the effects of circum-binary gas and eccentricity on the expected gravitational-wave sources from merging supermassive black hole binaries detectable by observatories like NANOGrav. -
Joyce Caliendo, University of Connecticut , "Early Science with the Large Millimeter Telescope: Constraining the Gas Fraction of a Compact Quiescent Galaxy at z = 1.883 ", Astronomy Seminar11:00am
3/3
Joyce Caliendo, University of Connecticut , "Early Science with the Large Millimeter Telescope: Constraining the Gas Fraction of a Compact Quiescent Galaxy at z = 1.883 ", Astronomy Seminar
Wednesday, March 3rd, 2021
11:00 AM - 11:30 AM
Storrs Campus online
Joyce Caliendo, University of Connecticut
Early Science with the Large Millimeter Telescope: Constraining the Gas Fraction of a Compact Quiescent Galaxy at z = 1.883
We present constraints on the dust continuum flux and inferred gas content of a gravitationally lensed massive quiescent galaxy at z=1.883 +/- 0.001 using AzTEC 1.1mm imaging with the Large Millimeter Telescope. MRG-S0851 appears to be a prototypical massive compact quiescent galaxy but has evidence that it experienced a centrally concentrated rejuvenation event in the last 100 Myr. This galaxy is undetected in the AzTEC image but we calculate an upper limit on the millimeter flux and use this to estimate the H_2 mass limit via an empirically calibrated relation that assumes a constant molecular gas-to-dust ratio of 150.
We constrain the 3 sigma upper limit of the H_2 fraction from the dust continuum in MRG-S0851 to be M_(H_2)/M_* < 6.8%. MRG-S0851 has a low gas fraction limit with a moderately low sSFR owing to the recent rejuvenation episode, which together results in a relatively short depletion time of -
Dr. H. Larsson, California Institute of Technology, "Molecules in quantum motion --- Understanding electrons, nuclei, and their interactions", Atomic, Molecular, And Optical Physics Seminar4:00pm
3/1
Dr. H. Larsson, California Institute of Technology, "Molecules in quantum motion --- Understanding electrons, nuclei, and their interactions", Atomic, Molecular, And Optical Physics Seminar
Monday, March 1st, 2021
04:00 PM - 05:00 PM
Storrs Campus online
Dr. H. Larsson, California Institute of Technology
Molecules in quantum motion ---
Understanding electrons, nuclei, and their interactions
In order to fully understand the chemical physics of molecular systems, we need to simulate both the electronic and vibrational motion quantum mechanically. However, simulations of quantum many-body systems, such as molecules, scale exponentially with system size. I will explain how to tame this 'curse of dimensionality' by combining methods from the traditionally disjoint fields of electronic structure and nuclear dynamics. This combination has enabled the simulation of complex systems with unprecedented accuracy and speed. I will demonstrate how these methods make it possible to solve a diverse set of problems, ranging from characterizing hydrated protons on a molecular quantum level to the interaction of molecules with extremely short and intense light pulses on attosecond time scales. I will demonstrate how these simulations provide new insight into complex fundamental physical processes. -
Prof. Stella Offner, UT Austin, "Physics Department Colloquium", Professor Stella Offner (Physics Colloquium)3:30pm
2/26
Prof. Stella Offner, UT Austin, "Physics Department Colloquium", Professor Stella Offner (Physics Colloquium)
Friday, February 26th, 2021
03:30 PM - 04:30 PM
Storrs Campus remote
Prof. Stella Offner, UT Austin
Physics Department Colloquium
Title and abstract: TBD -
Graduate Student Yasaman Homayouni, Department of Physics, University of Connecticut, PhD Dissertation Defense1:00pm
2/26
Graduate Student Yasaman Homayouni, Department of Physics, University of Connecticut, PhD Dissertation Defense
Friday, February 26th, 2021
01:00 PM - 03:00 PM
Storrs Campus Video meeting
Graduate Student Yasaman Homayouni, Department of Physics,
University of Connecticut
Supermassive black holes are among the most exciting and unusual objects in our Universe, as literal rips in space and time. Reliable measurements of mass, the structure, and geometry of infalling material to supermassive black holes are critical to understanding the growth history of black holes and galaxy formation and evolution over cosmic time. Beyond the local Universe, the gold standard for black hole mass and accretion-disk structure is reverberation mapping. I will present a new generation of industrial-scale study of the structure, and geometry of infalling material and black hole mass studies from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project and Ultraviolet-monitoring using the Hubble Space Telescope. These new measurements have transformed our understanding of supermassive black holes by dramatically expanding the number of quasars with reliable mass and accretion structure in distant Universe. These measurements have also revealed a surprisingly large diversity in accretion structure and the broad-line region size of quasars at the peak of supermassive black hole assembly. My work lays the foundation by developing the framework to reliably measure mass and the structure of accretion using direct disk size measurements from future massive time-domain photometric monitoring studies from SDSS-V and Rubin/LSST.
Webex link: https://uconn-cmr.webex.com/join/jot16106 -
Prof. Nora Berrah, Department of Physics, University of Connecticut, "Probing Molecular Dynamics in Real Time with Fancy Lasers", Graduate Student Seminar12:15pm
2/26
Prof. Nora Berrah, Department of Physics, University of Connecticut, "Probing Molecular Dynamics in Real Time with Fancy Lasers", Graduate Student Seminar
Friday, February 26th, 2021
12:15 PM - 01:15 PM
Storrs Campus online
Prof. Nora Berrah, Department of Physics, University of Connecticut
Probing Molecular Dynamics in Real Time with Fancy Lasers
The knowledge of the earliest time dynamics in molecular photophysics is critical because its role is to harness the energy from photons, initiating electronic and nuclear motion which is
fundamental in many areas of science. Our ultimate goal is to understand the coupled electronic and nuclear dynamics induced by the absorption of photons by molecules, which leads first to attosecond electron excitation within the molecules, followed by nuclear motion in the femtosecond range. This eventually results in the breaking and making of chemical bonds on the
picosecond timescale.
Our UConn lab uses ultrafast table-top lasers and a Cold Target Recoil-Ion Momentum
Spectroscopy (COLTRIMS) with IR and UV to determine processes such as double-H migration
in molecules as demonstrated by our recent work by McDonnel et al., "Ultrafast laser-induced
isomerization dynamics in Acetonitrile", J. Phys. Chem. Lett. 11, 6724−6729 (2020).
The past decade has seen the exciting birth of the first X-ray laser, the LCLS free electron laser (FEL) followed by other FELs around the world, leading to an explosion of new science, in the femtosecond and very recently in the attosecond regime. Our recent time-resolved experimental results using pump-probe technique with FELs to watch, in real time, the response of large
molecules to intense X-rays is included in Berrah et al., "X-ray multiphoton ionization of molecules: Femtosecond-resolved observation of delayed fragmentation and evaporation of neutral atoms", Nature
Physics 15, 1279 (2019).
We also investigate inner-shell molecular ionization and fragmentation dynamics of large
molecules using differential techniques such as double velocity map imaging (VMI) spectrometers to carry out electron-ion and ion-ion coincidence experiments at the ALS synchrotron at LBNL,
that allowed detail measurements such as our recent work by Obaid et al., "Intermolecular Coulombic decay in endohedral fullerene at the 4d→ 4f resonance", Phys. Rev Lett. 124 (11), 113002, (2020).
This work is funded by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic
Energy Sciences, Office of Science, US Department of Energy and the NSF. -
Dr. Jean Marcel Ngoko Djiokap, Department of Physics & Astronomy, University of Nebraska, Lincoln, "Control of Electron Motion on an Attosecond Timescale ", Atomic, Molecular, And Optical Physics Seminar4:00pm
2/24
Dr. Jean Marcel Ngoko Djiokap, Department of Physics & Astronomy, University of Nebraska, Lincoln, "Control of Electron Motion on an Attosecond Timescale ", Atomic, Molecular, And Optical Physics Seminar
Wednesday, February 24th, 2021
04:00 PM - 05:00 PM
Storrs Campus online
Dr. Jean Marcel Ngoko Djiokap, Department of Physics & Astronomy, University of Nebraska, Lincoln
Control of Electron Motion on an Attosecond Timescale
Technological advances 20 years ago in producing new extreme ultraviolet coherent light sources with attosecond duration have created a new research field, namely, attosecond physics. A main goal of attosecond physics is to control electron motion on its natural (attosecond) timescale, in order to probe bond formation and breaking in molecules during chemical reactions. A milestone toward achieving such goal is the experimental realization of isolated, few-cycle, attosecond pulses seeded by a free electron laser (FEL) or high harmonic generation (HHG) with stable and tunable carrier-envelope phase (CEP), and with full control of their polarizations. Unlike HHG, X-ray attosecond pulses from FEL have sufficient intensities that permit the realization of the holy grail (atto-pump/atto-probe experiments) of attosecond physics. Use of circularly or elliptically polarized attosecond light opens the possibility of presently investigating and manipulating linear and nonlinear effects that are not accessible with linearly-polarized pulses. In this talk, after briefly introducing the physical mechanisms at the basis of attosecond pulse generation, I will focus on our numerical and analytical methods for the investigation of ultrafast ionization processes in atoms and molecules of astrophysical interest, with emphasis on two-electron processes in which electron correlations play a key role. Enabled by the broad bandwidth of attosecond pulses, the first unusual effect we predicted in double photoionization of H2 by an intense few-cycle elliptically polarized attosecond pulse is the molecular symmetry-mixed dichroism (MSMD. The other effect is the novel electron phenomenon of electron vortices in attosecond photoionization of atoms and molecules, which provides a dramatic example of wave-particle duality. Our predictions of electron matter-wave vortices, which have now been observed experimentally, have already opened a new interdisciplinary area in physics.