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Colloquium

Fall 2022 Colloquia will be held in Room 307 of the Science and Engineering Research Facility (unless slated as virtual in the schedule below) on Mondays at 3:30 PM, EST.

Fall Colloquium Chair, Yuri Kamyshkov (kamyshkov@utk.edu)
Colloquium Fall 2022 Calendar


Colloquium Archives
Fall 2022 Schedule
Date
Speaker
Title
Host

August 29

Nadia Fomin
UT Physics

Don't stand so close to me - a story of short-range nuclear repulsion

Yuri Kamyshkov

September 5

Labor Day Holiday

No Colloquium

 

September 12

Steve Johnston
UT Physics
Slides

Intertwined spin, charge, and pair correlations in the two-dimensional Hubbard model

Yuri Kamyshkov

September 19

Haidong Zhou
UT Physics
Slides

The search and detection of quantum spin liquid in new materials with geometrically frustrated lattice

Yuri Kamyshkov

September 26

Christine Nattrass
UT Physics
Slides

Quantifying properties of liquid nuclei

Yuri Kamyshkov

October 3

Bronson Messer
Oak Ridge National Laboratory
Slides

Frontier: The world’s most powerful supercomputer

Raph Hix

October 10

Hanno Weitering
UT Physics
Slides

Recreating cuprate physics on a silicon platform

Yuri Kamyshkov

October 17

Peter Lepage
Cornell University

(Almost) 50 years of lattice QCD

Lucas Platter

October 24

Martin Mourigal
Georgia Tech

Magnon interactions, pairing, decay and fractionalizationin triangular lattice magnets

Cristian Batista

October 31

Anthony Mezzacappa
UT Physics
Slides

Agarrar la onda! Gravitational waves from core collapse supernovae

Raph Hix

November 7

Bernd Rosenow
University of Leipzig

New evidence for anyons: collisions and braiding

Adrian Del Maestro

November 14

Sarah Demers
Yale University

What to expect from CERN's Run 3

Larry Lee

November 21

Tom Handler
UT Physics

Science and public policy

Yuri Kamyshkov

November 28

W. Michael Snow
Indiana University
Slides

Nuclear/particle/astrophysics with neutrons

Yuri Kamyshkov

December 5

Minsu Kim
Emory University

Probing bacterial response to antibiotics at single cell resolution

Jaan Mannik

Spring 2023 Schedule
Date
Speaker
Title
Host

January 23

Department Town Hall Meeting

 

Adrian Del Maestro

January 30

Jérôme Margueron
Institut de Physique des 2 infinis

 

Andrew Steiner

February 6

Tao Han
University of Pittsburgh

"Who Ordered That?"--- Muons For New Physics

Yuri Kamyshko

February 13

Qi Li
Pennsylvania State University

 

Jian Liu

February 20

Steven Prohira
University of Kansas

 

Thomas Papenbrock

February 27

OPEN

 

 

March 6

David Radice
Pennsylvania State University

 

Anthony Mezzacappa

March 13

SPRING BREAK

NO COLLOQUIUM

 

March 20

Ken Burch
Boston College

 

Yishu Wang

March 27

Andrey Chubukov
University of Minnesota

 

C.D. Batista

April 3

Joel Moore
UC Berkeley

 

Alan Tennant

April 10

Bryan Ramson
FNAL

 

Nadia Fomin

April 17

Marcel Franz
UBC

 

Ruixing Zhang

April 24

Michael Peskin
Stanford University

 

Tova Holmes

May 1

Gail McLaughlin
North Carolina State University

 

Anthony Mezzacappa

May 8

HONORS DAY

 

 


Abstracts

August 29 | Nadia Fomin, UT Physics
Don't stand so close to me - a story of short-range nuclear repulsion

Much of what we know about high-energy components of nuclear structure comes from recent measurement campaigns at Jefferson Lab. Experiments from the 6 GeV era have provided precise results about short-range nucleon-nucleon correlations and their nuclear dependence. Additionally, an intriguing correlation was observed to measurements of modifications of nuclear quark distributions (EMC effect). I will highlight key insights gained from previous measurements (including recent ones) and present future experiments aimed at further illuminating these exotic components of nuclear structure.


September 12 | Steve Johnston, UT Physics

Slides

Intertwined spin, charge, and pair correlations in the two-dimensional Hubbard model

Understanding the physics of the high-temperature superconducting cuprates remains a grand challenge for condensed matter physics. The central difficulty here is that the cuprates host a rich set of novel magnetic and charge correlations that can compete/cooperate with superconductivity in ways that are not yet fully understood. In recent years, state-of-the-art nonpertubative numerical calculations for the single-band Hubbard model, a minimal model for the cuprates, have observed similar behavior with several nearly degenerate states closely competing for the ground state. This talk will discuss such numerical studies, including our recent work accessing these physics in the thermodynamic limit, where we find evidence for novel pair-density-wave correlations intertwined with the stripe correlations. I will also discuss how perturbations like the electron-lattice interaction can alter the balance between these competing orders.


September 19 | Haidong Zhou, UT Physics

Slides

The search and detection of quantum spin liquid in new materials with geometrically frustrated lattice

While the rise of quantum computers may one day help solve complex problems and deliver information with unhackable security, there is lack of a material platforms for scalable realization of quantum technologies. For instance, the most interesting magnetic property of the celebrated quantum spin liquids (QSLs) is the possibility of quantum mechanical encryption and transport of information, protected against environmental influences. Despite extensive studies on QSLs, they are still far away from applications. First obstacle is simply the shortage of real examples of QSL systems. Second obstacle is that most of the studied QSLs are insulators and electronically inert, which is incompatible with an electrical circuit that relies on moving charge carriers. The grand challenge is to find a way to convert the entanglement information into mobile charge signal by "metallizing" quantum magnets.

In this talk, I will introduce a unique approach by using strategical materials design focusing on geometrically frustrated magnets to address these two obstacles. First, we search for QSL in new spin-1/2 triangular lattice antiferromagnets. The two examples are Na2BaCo(PO4)2 and YbMgGaO4. Second, we explore how to electronically detect the spin sates and spin excitations in newly designed heterostructures based on pyrochlore lattice. The two examples are Dy2Ti2O7/Bi2Ir2O7 and Yb2Ti2O7/Bi2Ir2O7.

I will also introduce the crystal growth techniques used to synthesize these systems since the materials growth is the starting point of materials research and the high quality samples are essential to learn their intrinsic properties.


September 26 | Christine Nattrass, UT Physics

Slides

Quantifying properties of liquid nuclei

At energy densities above about 1 GeV/fm^3 QCD predicts a phase transition in nuclear matter to a plasma of quarks and gluons. This matter, called a Quark Gluon Plasma (QGP), has different properties from normal nuclear matter due to its high temperature and density and can be created in high energy nuclear collisions. Measurements at the Relativistic Heavy Ion Collider (RHIC) on Long Island and the Large Hadron Collider (LHC) in Geneva allow studies of nucleus-nucleus collisions over two orders of magnitude in center of mass energy. I will discuss how we can measure the properties of the QGP, even though the liquid produced in these collisions only lives around 10^{-23} seconds, and how we get the most out of those data. I will also discuss incorporation of undergraduates in these studies in a Course-based Undergraduate research experience (CURE). This provides a valuable educational experience for undergraduates while also assisting collaborations and the field with data preservation and comparisons to models. CUREs are a useful tool for increasing research opportunities in the department, increasing diversity in the field, and improving retention in the major.


October 3 | Bronson Messer, Oak Ridge National Laboratory

Slides

Frontier: The world’s most powerful supercomputer

The first exascale computer, called Frontier, has been delivered to Oak Ridge National Laboratory this past year. This unique scientific instrument is the culmination of more than a decade of concerted effort. I will relate a bit of the history of hybrid-node computing at the Oak Ridge Leadership Computing Facility (OLCF) and how Frontier represents the latest iteration of that approach. Some details of Frontier’s architecture will be discussed, including an overview of the new AMD GPUs that provide the bulk of the computational power for Frontier. Finally, we will take a look at some physics problems that will benefit from the increased capability at exascale, including the last great classical physics problem of turbulence. I will pay particular attention to the effects of turbulent mixing on the explosion mechanism of thermonuclear supernovae, a problem we recently studied on Frontier’s predecessor, Summit.


October 10 | Hanno Weitering, UT Physics

Slides

Recreating cuprate physics on a silicon platform

Discovered in 1986, the cuprate superconductors hold the record for highest superconducting transition temperature (139 K) under ambient pressure. These quasi two-dimensional materials are structurally and electronically very complex, and so is the origin of their spectacular superconducting properties. In this talk, I’ll review some key physical aspects of these materials and show how these insights can be applied successfully to establish two-dimensional superconductivity on the simplest and most ubiquitous electronic materials platform: Silicon. By decorating a p-type Si(111) surface with a dilute monatomic tin layer, we constructed a chiral d-wave superconductor with a critical temperature of up to 9 Kelvin and an upper critical field in excess of 15 Tesla. Chiral d-wave superconductivity is a very rare and exotic state of matter that is characterized by broken time-reversal symmetry and the presence of co-propagating edge modes that are potentially interesting for topological quantum computing. The simplicity and experimental control of simple adsorbate systems may provide a powerful testbed for theoretical models and discovery of elusive phases of quantum matter.


October 17 | Peter Lepage, Cornell University
(Almost) 50 years of lattice QCD

Lattice QCD was invented in 1973-74 by Ken Wilson, who passed away in 2013. This talk will describe the evolution of lattice QCD through the past almost 50 years with particular emphasis on its first years, and on the past two decades, when lattice QCD simulations finally came of age. Thanks to theoretical breakthroughs in the late 1990s and early 2000s, lattice QCD simulations now produce the most accurate theoretical calculations in the history of strong-interaction physics. They play an essential role in high-precision experimental studies of physics within and beyond the Standard Model of Particle Physics. The talk will include a non-technical review of the conceptual ideas behind this revolutionary development in (highly) nonlinear quantum physics, together with a survey of its current impact on theoretical and experimental particle physics, and prospects for the future.


October 24 | Martin Mourigal, Georgia Tech
Magnon interactions, pairing, decay and fractionalization in triangular lattice magnets

One of the scientific frontiers in quantum magnetism is the discovery and understanding of quantum entangled and topologically ordered states in real bulk materials. At the focal point of the experimental investigation of these quantum spin networks is the identification of fractionalized excitations in transport and spectroscopic measurements. Inelastic neutron scattering has proved a powerful technique to reveal such signatures in a variety of systems ranging from quasi-1D magnets to kagome compounds and more. Recent and on-going developments with neutron scattering instrumentation have allowed the characterization of magnetic excitations in entire volumes of momentum-energy space with high resolution. I this talk, I will discuss how triangular-lattice antiferromagnets, in several different shape and forms, are an ideal testbed for many-body physics. This work was supported by DOE/BES under award DE-SC-0018660 and NSF under award DMR-1750186.


October 31 | Anthony Mezzacappa, UT Physics

Slides

Agarrar la onda! Gravitational waves from core collapse supernovae

The first detection by the Laser Interferometer Gravitational Observatory (LIGO) of gravitational waves from merging black holes 1.3 billion light years away opened a new window on the Universe. The detection occurred nearly one hundred years after the publication of Einstein’s theory of general relativity (gravity), which predicted the existence of such waves, though Einstein himself doubted their existence and that we would ever be able to detect them. Three primary sources of gravitational waves detectable by LIGO are black hole mergers, neutron star mergers, and core collapse supernovae. Gravitational waves from the first two sources have been detected but not from the last. The last source will be the quintessential multi-messenger source, detectable for a Galactic event in gravitational waves, neutrinos, and photons across the electromagnetic spectrum. What we will learn from such a detection will depend on the sophistication of our core collapse supernova models. The UT–ORNL supernova group is well positioned to provide theoretical input to the gravitational wave astronomy community, in general, and the LIGO Scientific Collaboration, in particular, as we prepare for this watershed event. I will begin with a brief introduction to Einstein’s theory of gravity, without which the concept of a gravitational wave cannot be understood. I will then discuss gravitational waves and past milestone events in which they were detected from each of the first two sources listed above. Results from efforts by the UT–ORNL supernova group to predict core collapse supernova gravitational waveforms will be presented, as well as their implications for detection and culling from a detection information about the supernova central engine. I will then conclude and provide my outlook on the field.


November 7 | Bernd Rosenow, University of Leipzig
New evidence for anyons: collisions and braiding

Fermions and bosons are fundamental realizations of quantum statistics, which governs both the symmetry of the wave function under the interchange of particle coordinates and the probability for two particles being close to each other spatially. Anyons in the fractional quantum Hall effect are an example for quantum statistics intermediate between bosons and fermions. Two recent experiments have provided evidence for such exotic anyonic statistics: the collision of anyons in a mesoscopic setup has demonstrated that anyons indeed have a reduced spatial exclusion as compared to fermions, and the symmetry of the quantum mechanical wave function for anyons has been measured directly by braiding anyons around each other in a Fabry-Perot interferometer. I will focus on the theoretical description of anyon collisions, which provides an interesting application of non-equilibrium bosonization.


November 14 | Sarah Demers, Yale University
What to expect from CERN's Run 3

CERN's Large Hadron Collider has officially embarked on Run 3 after a multi-year shutdown, providing collisions at higher center-of-mass energy and enabling a more efficient delivery of data to the detectors. In this talk I will describe what we hope to learn from Run 3 and future runs of the LHC at the ATLAS Experiment, and the innovations that are helping us make forward progress in our understanding of the fundamental particles of the universe and the forces between them.


November 21 | Tom Handler, UT Physics
Science and Public Policy

The last several years have seen scientists being called upon to offer advice and recommendations with regards to several "crises" that have been impacting both the United States and the world at large. How has the role that science and scientists played been perceived? Science also plays a larger role in the lives of citizens. Examples being in nano-technology, human genomics, modified food crops, and fracking to name several. How should scientists respond to requests for advice and/or solutions? Are there any problems or pitfalls in the process of advising and forming policy?


November 28 | W. Michael Snow, Indiana University

Slides

Nuclear/Particle/Astrophysics with Neutrons

Experiments with slow neutrons can address interesting scientific questions in nuclear/particle/astrophysics and cosmology. I will present a few examples of issues and experiments from this subfield of scientific activity.


December 5 | Minsu Kim, Emory University
Probing bacterial response to antibiotics at single cell resolution

Ineffective use of antibiotics leads to treatment failure and emergence of antibiotic resistance. One major challenge in the field is that our understanding of bacterial response to antibiotics is limited. The research in my lab focuses on quantitatively understanding the effects of antibiotics on bacterial cells and the population. In this talk, I will discuss our on-going research on stochastic population dynamics of bacteria treated with antibiotics. I will present our data that bacterial clearance does not follow a deterministic course but is highly probabilistic. These population fluctuations may be manipulated to facilitate bacterial eradication.


Spring 2023 Abstracts

February 6 | Tao Han, University of Pittsburgh
"Who Ordered That?" --- Muons For New Physics

Who Ordered That? I.I. Rabi asked this question when a new particle, the muon, was discovered in 1936. Ever since, this unexpected particle has constantly brought us more surprises, including the pion discovery, parity violation, J/psi discovery, neutrinos and flavor physics etc., opening an avenue in front of us to new physics and new technology. In this talk, I will discuss a new aspect — a high energy muon collider. Due to the recent technological breakthroughs for muon cooling, the muon collider program has regained its momentum. I will present the idea and the current status for a muon collider, and discuss the rich physics potential in exploring the physics beyond the Standard Model, for two representative scenarios: the Higgs factory for the resonant Higgs production and the multi-TeV muon collider at the energy frontier.


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