For more information about this series, please contact the colloquium coordinator.
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UConn Physics Colloquium2:30pm 2/14
UConn Physics Colloquium
Friday, February 14th, 2025
02:30 PM - 03:30 PM
Gant West Building GW-002
Dr. Dima Kharzeev, Stony Brook University and Brookhaven National Laboratory
When Physics meets Quantum information
The interplay between physics and quantum information drives profound advancements in our understanding of nature, reshaping fundamental concepts and enabling groundbreaking technologies. In this colloquium, we will explore how quantum information and physics intersect, influencing and transforming each other.
I will discuss the role of entanglement in quantum matter (both in and out of equilibrium), quantum computation as a powerful tool for simulating complex physical systems, and the impact of information-theoretic principles on nuclear, high-energy, and condensed matter physics. By bridging the gap between these fields, we unlock new avenues for discovery and pave the way for technological breakthroughs.
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UConn Physics Colloquium2:30pm 2/7
UConn Physics Colloquium
Friday, February 7th, 2025
02:30 PM - 03:30 PM
Gant West Building GW-002
Prof. Victor S. Batista, Department of Chemistry, Yale University and Yale Quantum Institute
Simulating Dynamics on Bosonic Quantum Devices
Bosonic quantum devices offer a novel approach to realize quantum computations, where the quantum two-level system (qubit) is replaced with the quantum (an)harmonic oscillator (qumode) as the fundamental building block of the quantum simulator. The simulation of chemical structure and dynamics can then be achieved by representing or mapping the system Hamiltonians in terms of bosonic operators. In this talk, we review recent progress and future potential of using bosonic quantum devices for addressing a wide range of challenging chemical problems, including the calculation of molecular vibronic spectra, the simulation of adiabatic and nonadiabatic chemical dynamics, quantum machine learning applications for characterization of molecular systems, molecular docking of molecular graph theory problems, and the calculations of electronic structure
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UConn Physics Colloquium3:00pm 12/6
UConn Physics Colloquium
Friday, December 6th, 2024
03:00 PM - 04:00 PM
Gant West Building GW-002
Dr. Taran Driver, PULSE institute and SLAC National Accelerator Laboratory and Linac Coherent Light Source
Probing Correlated Multi-Electron Dynamics on the Attosecond Timescale
The interaction of light with matter is a fundamental process for probing and engineering the quantum properties of a molecule or material. This interaction is mediated by electrons, and understanding the many-body dynamics of electronic systems in the first moments following light-driven excitation is a frontier challenge. The characteristic timescale for this electron motion is set by the splitting of the relevant energy levels, which results in motion on the attosecond (10-18 s) timescale. It is now possible to generate pulses of light lasting on the order of one hundred attoseconds, both on the tabletop in the laboratory and at large free-electron laser facilities. I will present recent work using attosecond x-ray pulses to probe the ultrafast dynamics of multi-electron systems. We measured the photoemission delay in the core-level ionization of a molecule. This is the delay between the arrival of a photon and the emission of an electron in photoionization, which was long considered an instantaneous process. In fact, this delay reveals strong modulations due to electron correlation. We also time-resolved the response of an aromatic molecule, para-aminophenol, to impulsive photoionization. By accessing the dynamics within the first femtosecond following the removal of an electron, we observed the interplay between the sub-femtosecond decay of shake-up states and coherent charge density oscillation on the few-femtosecond timescale. I will also touch on future directions which will harness these new methods to develop ultrafast probes of electron motion and exotic light-engineered states in quantum materials.
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UConn Physics Colloquium3:30pm 11/22
UConn Physics Colloquium
Friday, November 22nd, 2024
03:30 PM - 04:30 PM
Gant West Building GW-002
Prof. Lina Necib, Department of Physics, MIT
Mapping out the Dark Matter in the Milky Way
In this talk, I will explore the interfacing of simulations, observations, and machine learning techniques to construct a detailed map of Dark Matter in the Milky Way, focusing on the Galactic Center/Halo and dwarf galaxies. For the Galactic Halo, I will present a recent work that reveals a decline in the stellar circular velocity, inducing tensions with established estimates of the Milky Way’s mass and Dark Matter content. I will discuss how the underestimated systematic errors in such a common methodology necessitates a revised approach that combines theory, observations, and machine learning. In dwarf galaxies, I will present a novel Graph Neural Network methodology that facilitates the accurate extraction of Dark Matter density profiles, validated against realistic simulations. I will conclude with a discussion on the future trajectory of astroparticle physics, emphasizing the need for the integration of astrophysical probes with experimental Dark Matter research, potentially leading to a better understanding of the nature of Dark Matter.
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UConn Physics Colloquium3:30pm 11/8
UConn Physics Colloquium
Friday, November 8th, 2024
03:30 PM - 04:30 PM
Gant West Building GW-002
Prof. Philip Mannheim, University of Connecticut
The Accelerating Universe
I will describe some of the background that led to the award of the Nobel prize to Dr. Adam Riess, who will be our 2024 Katzenstein speaker on November 15.
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UConn Physics Colloquium3:30pm 11/1
UConn Physics Colloquium
Friday, November 1st, 2024
03:30 PM - 04:30 PM
Gant West Building GW-002
Prof. Matthew Guthrie, University of Connecticut;
A New Era for Connecticut’s Oldest Planetarium: Historic Roots to Modern Revival
The UConn Planetarium, built in 1954, has long been a central resource for astronomy education and outreach at the University of Connecticut. In this talk, I will present an overview of the planetarium’s historical roots at UConn, its significance in the community, and the extensive renovations we have completed to bring this important facility back to life. After years of disuse, the planetarium has been fully upgraded with modern technology and will officially reopen on November 1st, immediately following this colloquium.
Our efforts to restore the planetarium are guided by the legacy of Dr. Cynthia Peterson, UConn’s first woman physics faculty member and a pioneer in science education. The planetarium now officially bears her name as the Cynthia Wyeth Peterson Memorial Planetarium, in honor of her decades of dedication to astronomy outreach. Following my presentation, Nora Berrah and Celeste Peterson will speak about Dr. Peterson’s life and achievements - how her contributions to UConn and the wider scientific community continue to resonate today.
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UConn Physics Colloquium3:30pm 10/25
UConn Physics Colloquium
Friday, October 25th, 2024
03:30 PM - 04:30 PM
Gant West Building GW-002
Prof. Philip Kim, Harvard University
Searching for Anyon in Quantum Materials
The search for anyons, quasiparticles with fractional charge and exotic exchange statistics, has inspired decades of condensed matter research. Moreover, it has been predicted that exchange braiding of these particles, especially non-abelian anyons, can produce topologically protected logic operations that can serve as building blocks for fault-tolerant quantum computing. In this talk, I will discuss the progress of research on two quantum materials platforms to realize these exotic particles. In the first example, we will discuss anyons arising in fractional quantum Hall (FQH) effects, using quantum Hall interferometers for direct observation of the anyon braiding phase around a confined cavity. In the second example, we will discuss our recent experimental efforts to realize non-abelian anyons in proximitized topological insulator surfaces by controlled manipulation of magnetic vortices containing non-abelian anyons.
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UConn Physics Colloquium3:30pm 10/18
UConn Physics Colloquium
Friday, October 18th, 2024
03:30 PM - 04:30 PM
Gant West Building GW-002
Prof. Jun Ye, University of Colorado and JILA
Title and abstract TBA
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UConn Physics Colloquium3:30pm 9/20
UConn Physics Colloquium
Friday, September 20th, 2024
03:30 PM - 12:00 AM
Gant West Building 002
Prof. Mingda Li, Nuclear Science and Engineering, MIT
Exploring Potential Roles of Machine Learning in Quantum Materials ResearchIn recent years, machine learning has achieved great success in chemistry and materials science, but quantum materials face unique challenges. These include the scarcity of data (volume challenge), high dimensionality and computational costs (complexity challenge), elusive experimental signatures (experimental challenge), and unreliable ground truth (validation challenge).
In this Physics Colloquium, we present our recent efforts to support the study of quantum materials with machine learning. For scenarios with high data volumes, such as density-functional-theory (DFT) level studies with weak correlation, machine learning can predict lower-dimensional properties. We introduce a convolutional neural network classifier predicting band topology class based on X-ray absorption (XAS) signals [1]. This approach can also be applied to experimental data, demonstrated by an autoencoder-based protocol to study the magnetic proximity effect with polarized neutron reflectometry, improving fitting resolution [2].
For lower data volumes due to higher computational costs, incorporating symmetry into neural networks can reduce data volume needs. Using the O(3) Euclidean neural network, we predict phonon density-of-states [3], dielectric functions [4], and quantum weight [5] directly from crystal structures. Machine learning without data can also be performed by using differential equations as constraints [5].
For high output dimensions and low input data volumes, such as phonon dispersion relations, we introduce additional approaches like virtual nodes in a graph neural network [6], showing improved efficiency compared to machine-learning potential without losing accuracy.
To address unreliable ground truth, we use machine learning to distinguish Majorana zero modes in scanning tunneling spectroscopy for topological quantum computation [7]. For cases like quantum spin liquids, where experimental signatures are unclear and computational costs are high, we generate materials with potential geometrical frustration. Our latest work, SCIGEN, produces eight million materials belonging to Archimedean lattices, with over 50% passing DFT stability checks after pre-screening [8].
Despite progress, applying machine learning to quantum materials is still in its infancy. We reflect on the out-of-distribution problem, aiming to generate genuine surprises and new features rather than merely recognizing patterns. Additionally, we must address accuracy limitations in many machine learning approaches, especially with complex quantum systems and phase diagram studies.
[1] “Machine learning spectral indicators of topology,” Advanced Materials 34, 202204113 (2022).
[2] “Elucidating proximity magnetism through polarized neutron reflectometry and machine learning,” Applied Physics Review 9, 011421 (2022).
[3] “Direct prediction of phonon density of states with Euclidean neural networks,” Advanced Science 8, 2004214 (2021).
[4] “Ensemble-Embedding Graph Neural Network for Direct Prediction of Optical Spectra from Crystal Structure,” arXiv:2406.16654.
[5] “Panoramic mapping of phonon transport from ultrafast electron diffraction and machine learning,” Advanced Materials 35, 2206997 (2023).
[6] “Virtual Node Graph Neural Network for Full Phonon Prediction,” Nature Computational Science 4, 522 (2024).
[7] “Machine Learning Detection of Majorana Zero Modes from Zero Bias Peak Measurements,” Matter 7, 2507 (2024).
[8] “Structural Constraint Integration in Generative Model for Discovery of Quantum Material Candidates,” arXiv:2407.04557.
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UConn Physics SPS Colloquium4:00pm 4/26
UConn Physics SPS Colloquium
Friday, April 26th, 2024
04:00 PM - 05:00 PM
Gant West Building GW-002
Prof.. Reina Maruyama,Yale University
What is dark matter?
Astrophysical observations give overwhelming evidence for the existence of dark matter. Several theoretical particles have been proposed as dark matter candidates, including weakly interacting massive particles (WIMPs), axions, and, more recently, their much lighter counterparts. However, there has yet to be a definitive detection of dark matter. For years, one group, the DAMA collaboration, has asserted that they observe a dark matter-induced annual modulation signal in their NaI(Tl)-based detectors. Their observations are inconsistent with those from other direct detection dark matter experiments under most assumptions of dark matter. In this talk, I will describe how I came to work on this topic and the debate’s current status, the worldwide experimental effort to test this extraordinary claim, and our progress toward resolving the current stalemate in the field.
Note: The pre-colloquium reception will be 3-4pm in the Gant Light Court
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Professor Cassandra Paul (UConn Physics Colloquium)3:30pm 4/19
Professor Cassandra Paul (UConn Physics Colloquium)
Friday, April 19th, 2024
03:30 PM - 04:30 PM
Remote Online
Prof. Cassandra Paul (San Jose State University)
Title and abstract (TBD)
Contact: Prof. Erin ScanlonRemote talk (details forthcoming)
Contact Information: no contact information was provided for this event
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Prof. Eric Heller, Harvard University (UConn Physics Colloquium)3:30pm 4/5
Prof. Eric Heller, Harvard University (UConn Physics Colloquium)
Friday, April 5th, 2024
03:30 PM - 04:30 PM
Gant West Building 002
TITLE:
Quantum acoustics and the physics of the strange metals
ABSTRACT:
Quantum acoustics is the analog of quantum optics, with phonons playing the role of photons. The classical fields (electromagnetic, acoustic) are reached by virtue of coherent states in both cases. Quantum acoustics leads to two time dependent, interacting wave fields, one lattice, one quantum. The electron diffuses at a Planckian rate, independent of electron-lattice coupling and temperature, and the calculated resistivity is linear in temperature. Mott-Ioffe-Regel and Drude peak mysteries are also resolved. A rather different carrier transport scenario emerges for the strange metals.
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Dr. Nick Hutzler, California Institute of Technology (UConn Physics Colloquium)3:30pm 3/29
Dr. Nick Hutzler, California Institute of Technology (UConn Physics Colloquium)
Friday, March 29th, 2024
03:30 PM - 04:30 PM
Gant West Building 002
Dr. Nick Hutzler, California Institute of Technology
UConn Physics Colloquium
Title and abstract: TBD
Contact: Profs. Tom Blum and Dan McCarron -
Dr. James Cryan, SLAC National Lab (UConn Physics Colloquium)3:30pm 3/22
Dr. James Cryan, SLAC National Lab (UConn Physics Colloquium)
Friday, March 22nd, 2024
03:30 PM - 04:30 PM
Gant West Building 002
Dr. James Cryan, SLAC National Lab (UConn Physics Colloquium)
Ultrafast dynamics using X-ray attosecond pulses.
Contact: Prof. Nora Berrah -
UConn Physics Colloquium (Dr. Andrew Held)3:30pm 3/8
UConn Physics Colloquium (Dr. Andrew Held)
Friday, March 8th, 2024
03:30 PM - 04:30 PM
Gant West Building 002
UConn Physics Colloquium: Dr. Andrew Held
High Power Commercial Laser Markets and Applications
Abstract: Ubiquitous and familiar applications for lasers include telecom data transmission, laser surgery (LASIK), information processing (DVD/Blue Ray), supermarket scanners, laser pointers and a multitude of laser sensing applications (LIDAR, range finders, facial recognition, etc.). Sophisticated laser technology is also well-recognized as a key, enabling research tool.Perhaps less well known are the “unsung” commercial applications and markets for higher power lasers. Often out of public view, these laser applications drive diverse and massive commercial markets and are supported by extensive industry-based research and development investments. And are generating increasingly abundant STEM based career opportunities.
The presentation will highlight the laser technologies and applications used in materials processing to mark, engrave, cut, and join everything from shoe leather to sheet metal. Also covered are laser applications supporting the manufacturing of microelectronics-based consumer technology, enabling higher performing devices and ever larger displays. The laser technology and developments that support emerging Directed Energy military applications will be also be reviewed.
Bio:
Andrew Held has recently retired as Senior Vice President of Coherent’ s Aerospace and Defense business. Andrew has over 30 years’ experience in General Business Management, Research, Sales and Marketing of lasers and photonics into a broad range of markets and applications. He received his B.S. in Chemistry and Ph.D. in Laser Spectroscopy from the University of Pittsburgh and was an Alexander von Humboldt Research Fellow at the Technical University in Munich.