UConn Physics showing strong at the 2023 APS March Meeting
This year, international conferences have begun to come back into their pre-pandemic form. For the American Physical Society’s annual March Meeting, it was bigger than ever with over 12,000 participants in the world’s largest meeting ever devoted to physics. UConn showed strong as graduate students, postdoctoral fellows, research scientists, and faculty researchers attended the meeting […]
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The passing of Dr. Garry Bent
Gary Dean Bent, 82, a former assistant head of the Physics Department at the University of Connecticut for 23 years, passed away on Friday, March 3, 2023. He was born on October 9, 1940, in Battle Creek, Michigan. Growing up in Florida, he studied at the Georgia Institute of Technology where he earned Bachelor’s and […]
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The Milky Way Laboratory Contributes to Art Exhibit at the University of Hartford
Prof. Cara Battersby’s research group, the Milky Way Laboratory, was invited to collaborate with Genevieve de Leon, the 2022-23 Koopman Distinguished Chair in the Painting Department at the University of Hartford, for an exhibition focused on the intersection between the Maya calendrical cycles and scientific studies of the cosmos. From the Milky Way Laboratory, H […]
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Prof. Jonathan Trump interviewed by The Conversation about JWST Discoveries
The Conversation interviewed Prof. Jonathan Trump about his recent work with the James Webb Space Telescope (JWST), with an article and podcast interview available at this link. The interview includes discussion of Prof. Trump’s recent journal paper that used spectroscopic observations from JWST to understand the chemical enrichment of galaxies in the early Universe.
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2023 HEAD Early-Career Prize is awarded to Prof. Mingarelli
The 2023 High Energy Astrophysics Division’s Early-Career Prize is awarded to Dr. Chiara Mingarelli for her leadership in the analysis of pulsar timing array data and her contributions to our understanding of the stochastic gravitational wave background.
[Read More]Recent Events
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Prof. Eleanor Close Texas State University, Prof. Eleanor Close, Texas State (Physics Colloquium)3:30pm
3/31
Prof. Eleanor Close Texas State University, Prof. Eleanor Close, Texas State (Physics Colloquium)
Friday, March 31st, 2023
03:30 PM - 04:30 PM
Storrs Campus GW-002
Prof. Eleanor Close
Texas State University
Title and abstract: TBD -
Prof. Alan Wuosmaa, Department of Physics, University of Connecticut, " "Exotic Nuclei" - What are they, how do we study them and why we should care?", Graduate Student Seminar12:15pm
3/31
Prof. Alan Wuosmaa, Department of Physics, University of Connecticut, " "Exotic Nuclei" - What are they, how do we study them and why we should care?", Graduate Student Seminar
Friday, March 31st, 2023
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. Alan Wuosmaa, Department of Physics, University of Connecticut
"Exotic Nuclei" - What are they, how do we study them and why we should care?
Just over one hundred years after their discovery by Rutherford, the nuclei of atoms are the focus of considerable renewed interest. Only about 300 nuclear isotopes are stable and can be found in nature, but nearly 3000 nuclei that are stable with respect to proton or neutron emission have been artificially produced in the laboratory. Our understanding of the behavior of the nucleus has largely been guided by ideas developed by studying the nuclei that are stable, however for unstable nuclei with a very large imbalance between protons and neutrons (so-called "exotic nuclei"), these ideas are proving insufficient. The experimental data needed to refine our understanding of the nucleus can only be obtained by performing reactions with short-lived radioactive nuclei. Experiments with such beams are difficult, and introduce many technical challenges. The data they can provide, however, are important not only to understanding nuclear structure, but many other situations such as the violent environments found in exploding stars in the cosmos. I will discuss some of the background behind studies of the structure of exotic nuclei, some modern experimental methods, and prospects for the future. -
Connor Occhialini, Massachusetts Institute of Technology, "Non-collinear magnetism and multiferroic order in atomically-thin van der Waals materials", Condensed Matter Physics Seminar2:00pm
3/29
Connor Occhialini, Massachusetts Institute of Technology, "Non-collinear magnetism and multiferroic order in atomically-thin van der Waals materials", Condensed Matter Physics Seminar
Wednesday, March 29th, 2023
02:00 PM - 03:00 PM
Storrs Campus GS-117
Connor Occhialini, Massachusetts Institute of Technology
Non-collinear magnetism and multiferroic order in atomically-thin van der Waals materials
The recent discovery of magnetic order down to the single-layer limit of van der Waals (vdW) materials has launched substantial interest in realizing functional properties associated to magnetoelectric or topological magnetic phases in two-dimensions (2D). One approach to realize such properties is through non-collinear magnetism, including spiral (e.g. helical/cycloidal) or skyrmionic spin textures. Here, I will discuss our recent work on the nickel dihalides (NiX2, X = Cl, Br, I) which are semiconducting triangular-lattice vdW magnets with frustrated exchange interactions from which non-collinear magnetic phases are stabilized in the bulk. In particular, NiI2 hosts an incommensurate helimagnetic ground state (Q = 0.138a* + 1.457c*) alongside a spin-induced ferroelectric order and is therefore a type-II multiferroic with TN ~ 60 K. We identified multiple optical signatures, including optical linear dichroism, second harmonic generation and Raman spectroscopy, which reflect the characteristic symmetry-breaking attributed to polar magnetism and allow us to track the multiferroic phase transition in atomically-thin samples. Our results provide evidence for the persistence of type-II multiferroic order down to the single-layer limit of NiI2 with a transition temperature of TN ~ 21 K. We conclude a helimagnetic order in the single-layer that is stabilized by anisotropic symmetric exchange and enhanced by a dimensionality-tuned interlayer interaction in multilayers. I will also discuss complementary optical and X-ray diffraction measurements at high-pressures which reveal a significant pressure enhancement of the multiferroic transition temperature in the bulk at a rate of 14.4 K/GPa. This observation is in quantitative agreement with first-principles calculations of the exchange interactions which reveal a stabilized helimagnetic order from pressure-enhanced interlayer and third-nearest neighbor intralayer exchange. These results provide a generalized route to realize intrinsic multiferroic order in 2D materials with high transition temperature.
References:
- Qian Song, Connor A. Occhialini, Emre Ergeçen, and Batyr Ilyas et al, "Evidence for a single-layer van der Waals multiferroic", Nature 602, 601-605 (2022).
- Connor A. Occhialini, Luiz G. P. Martins et al, "Pressure-stabilized magnetic phase transitions in van der Waals multiferroic NiI2" (In preparation, 2023). -
Zachary Harris, Department of Physics, University of Connecticut, "Resurgence in QED: Probing the Schwinger effect in inhomogeneous fields", Particle, Astrophysics and Nuclear Physics Seminar2:00pm
3/27
Zachary Harris, Department of Physics, University of Connecticut, "Resurgence in QED: Probing the Schwinger effect in inhomogeneous fields", Particle, Astrophysics and Nuclear Physics Seminar
Monday, March 27th, 2023
02:00 PM - 03:00 PM
Storrs Campus GS-119
Zachary Harris, Department of Physics, University of Connecticut
Resurgence in QED: Probing the Schwinger effect in inhomogeneous fields
The structure of the QED vacuum is a subject of great interest, especially as experiments begin to more directly probe the non-linear regime of the theory. One of the most striking features of the vacuum is its polarization in the presence of an electric field -- a non-perturbative phenomenon that leads to pair production. Detailed information about this non-perturbative structure is contained in the divergence of perturbation theory, which is more generally described by the theory of resurgence. We study the one-loop QED effective action for an exactly solvable, inhomogeneous background field configuration and use Borel summation to illustrate the connection between perturbative and non-perturbative regimes. Using only 15 terms in the weak magnetic field perturbative expansion, we extrapolate to both strong magnetic field and electric field configurations and obtain a pair-production rate that agrees with the exact effective action to remarkable precision. -
Prof. Barrett Wells, Department of Physics, University of Connecticut, " Extreme Tuning of Quantum Materials", Graduate Student Seminar12:15pm
3/24
Prof. Barrett Wells, Department of Physics, University of Connecticut, " Extreme Tuning of Quantum Materials", Graduate Student Seminar
Friday, March 24th, 2023
12:15 PM - 01:15 PM
Storrs Campus GS-119
Prof. Barrett Wells, Department of Physics, University of Connecticut
Extreme Tuning of Quantum Materials
I will describe recent research directions in my lab studying quantum materials with important properties. One set of work studies unusual and strange phase transitions, particularly a case where the change in symmetry with temperature is opposite of that expected. Another involves developing methods to study the atomic structure and electromagnetic properties of materials in the form of nanopillars, where they can be subjected to strain fields orders of magnitude higher than possible in normal sized materials. The discovery of superelasticity in nanopillars came from a UConn colleague studying the strength of materials. The technique appears to open a path towards extreme tuning of quantum properties if proper measurement techniques can be developed. Our group is working to enable nanodiffraction of the atomic structure under extreme strain.
In addition, I will make some general remarks about the department in my role as Department Head. -
Zachary Harris, Department of Physics, University of Connecticut, "Resurgence in QED: Probing the Schwinger effect in inhomogeneous fields", CANCELLED: Particle, Astrophysics and Nuclear Physics Seminar2:00pm
3/20
Zachary Harris, Department of Physics, University of Connecticut, "Resurgence in QED: Probing the Schwinger effect in inhomogeneous fields", CANCELLED: Particle, Astrophysics and Nuclear Physics Seminar
Monday, March 20th, 2023
02:00 PM - 03:00 PM
Storrs Campus GS-119
Zachary Harris, Department of Physics, University of Connecticut
Resurgence in QED: Probing the Schwinger effect in inhomogeneous fields
The structure of the QED vacuum is a subject of great interest, especially as experiments begin to more directly probe the non-linear regime of the theory. One of the most striking features of the vacuum is its polarization in the presence of an electric field -- a non-perturbative phenomenon that leads to pair production. Detailed information about this non-perturbative structure is contained in the divergence of perturbation theory, which is more generally described by the theory of resurgence. We study the one-loop QED effective action for an exactly solvable, inhomogeneous background field configuration and use Borel summation to illustrate the connection between perturbative and non-perturbative regimes. Using only 15 terms in the weak magnetic field perturbative expansion, we extrapolate to both strong magnetic field and electric field configurations and obtain a pair-production rate that agrees with the exact effective action to remarkable precision. -
Dr. Norah Hoffmann, Columbia University, "Light-Matter Interactions: From Classical to Quantum ", Atomic, Molecular, and Optical Physics Seminar2:00pm
3/9
Dr. Norah Hoffmann, Columbia University, "Light-Matter Interactions: From Classical to Quantum ", Atomic, Molecular, and Optical Physics Seminar
Thursday, March 9th, 2023
02:00 PM - 03:00 PM
Storrs Campus GS-117
Dr. Norah Hoffmann, Columbia University
Light-Matter Interactions: From Classical to Quantum
The influence of light plays a paramount role in our everyday life, from fundamental biological mechanisms to sustainable energy applications. Therefore, controlling and optimizing the underlying processes is of great interest.
The use of (oriented) classical electric fields to modify chemical reactions is a promising, emerging technique. In this talk, I will discuss a non-empirical linear free energy relationship that microscopically relates field-induced changes in the activation energy to those in the reaction energy, providing a powerful new framework for the design and characterization of electrostatic catalysis. On the other hand, experimental developments in the emerging field of polaritonic chemistry opened up new possibilities for modifying and controlling chemical processes that depend on the interaction of quantized light fields with matter. I will give an overview of the strong light-matter interaction that arises when the matter is confined in optical cavities, its computational challenges, and potential solutions focusing on mixed quantum-classical methods for photons. -
Dr. Han Fu, University of Chicago, "Nonequilibrium dynamics in ultracold atomic systems ", Atomic, Molecular, and Optical Physics Seminar2:00pm
3/6
Dr. Han Fu, University of Chicago, "Nonequilibrium dynamics in ultracold atomic systems ", Atomic, Molecular, and Optical Physics Seminar
Monday, March 6th, 2023
02:00 PM - 03:00 PM
Storrs Campus GS-117
Dr. Han Fu, University of Chicago
Nonequilibrium dynamics in ultracold atomic systems
The experimental advances in preparing, controlling, and probing ultra-cold atomic systems provide powerful platforms for the study of non-equilibrium dynamics of quantum systems. When trapped particles are subjected to external driving or undergo quantum quenches, they display a rich variety of emergent phenomena not accessible in an equilibrium state.
In this talk, I will discuss my recent works on driven ultracold Bose atoms based on Gross-Pitaevskii numerical simulations. When applying an oscillating magnetic field to the system, interactions between Bose atoms will change periodically in time. We find that this leads to the formation of 'Bose fireworks', a fascinating physical phenomenon demonstrating driven-induced amplification of quantum fluctuations. When we modulate our trapping potentials, the energy spectrum of Bose atoms forms an effective band structure. In this case, we discover that Bose atoms can condense via a highly nontrivial process. These findings not only lead to our proposal of a new imaging method to probe ultracold Bose systems, but also reveal key aspects of thermalization in quantum many-body systems.