The quantum world of quarks and gluons on a quantum simulator?

The strong force in nature, described by the quantum and relativistic framework of quantum chromodynamics or QCD, has long generated an active and growing field of research and discovery. In fact, despite its development over many decades ago, it still leaves us with plenty of exciting questions to explore in the 21st century, with a multi-billion-dollar experimental investment that aims to understand the core of matter: Can we learn the phase diagram of matter governed by strong interactions? Can we predict how matter evolves and thermalizes after energetic processes such as in the early universe or in terrestrial particle colliders? How do elementary particles in QCD, quarks and gluons, and their interactions give rise to the complex structure of a proton or a nucleus? While an extremely successful theoretical and computational program called lattice QCD has enabled a first-principles look into some properties of matter, we have yet to come up with a computationally more capable tool to predict the complex dynamics of matter from the underlying interactions. Can a large reliable (digital or analog) quantum simulator eventually enable us to study the strong force? What does a quantum simulator have to offer to simulate QCD and how far away are we from such a dream? In this talk, I will describe a vision for how we may go on a journey toward quantum simulating QCD, by taking insights from early to late developments of lattice QCD, by motivating the need for novel theoretical, algorithmic, and hardware approaches to quantum-simulating this unique problem, and by providing examples of the early steps taken to date in establishing a quantum-computational lattice-QCD program.

Prospecting for dark matter in the Black Hills of Dakota

Dark matter outweighs ordinary matter in the cosmos by about a factor of five, yet its fundamental constituents remain unknown to us. At the Sanford Underground Research Facility in Lead, South Dakota, we have recently begun a new search for exotic WIMP particles that might comprise the dark matter. Besides providing an explanation for the large scale structure of the universe, an observation of WIMPs would open a window on high energy physics beyond the standard model. Our experiment is called LZ (LUX-ZEPLIN), and it now joins the Panda-X and XenonNT experiments at the frontier of this field. The experiment is working well and is expected to explore about one order of magnitude in WIMP scattering cross sections in the next few years. LZ will also have sensitivity to neutrinoless double beta decay, a process which can reveal the basic nature of neutrino mass. We will review the status of these new physics searches and discuss what may lie ahead in the next decade.

Particle Physics in the Sky : From Theory to Experiment and Back

We present two examples of how searches for underlying principles interface with exciting new CMB and gravitational wave experiments.  First, the quantization of electric charge leads us to consider axion strings that have an Aharonov-Bohm-like effect on the CMB photons.  This polarization rotation leads in turn to a novel experimental analysis.  Second, if a stochastic gravitational wave signal were to be discovered, an analysis of the frequency spectrum would allow us to measure the free streaming fraction and equation of state of the early universe and, surprisingly, even the beta function of QCD at high energies. 

Structured Light and Darkness in Nanophotonics

When multiple light beams overlap in three-dimensional space, their interference produces lines of complete darkness – optical vortices that can form closed loops – links or knots. In this talk, we discuss how the synergy of structured light and darkness with nanostructured photonic media could bring new dimensions to the science and applications of light. Today, the term “structured light” describes a variety of optical waveforms with the spatial inhomogeneity of one or more physical parameters in two- or three-dimensional space and time. Topological concepts once considered mostly in the domain of abstract mathematics or theoretical physics, such as singularities of the phase or polarization, topological textures, and spin-orbit interactions nowadays are entering the field of classical and quantum optics. We design all-dielectric optical nanostructures enabling unprecedented control over the amplitude, phase, and polarization of optical fields, for generation of optical beams with an orbital angular momentum (OAM), as well as optical links and knots, and study their stability in linear and nonlinear media. For example, by exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a single-mode OAM microring laser. Next, using the mathematical framework of supersymmetry, we design and demonstrate a stable two-dimensional microlaser array that is scalable and could prove to be a practical platform for developing complex nanophotonic systems. Finally, we discuss a new family of null solutions to the Helmholtz equation in three-dimensional free space - optical links and knots, their generation and robustness in the presence of atmospheric turbulence, and their interactions with nonlinear optical media.

Bio: Natalia Litchinitser is a Professor of Electrical and Computer Engineering and a Professor of Physics at Duke University. Her research focuses on linear and nonlinear optics in engineered nanostructures, metamaterials, topological photonics, as well as the engineering of the light beams themselves. Natalia M. Litchinitser earned her Ph.D. degree in Electrical Engineering from the Illinois Institute of Technology and a Master’s degree in Physics from Moscow State University in Russia. She completed her postdoctoral training at the Institute of Optics, the University of Rochester in 2000. Natalia Litchinitser previously was a Professor of Electrical Engineering at the University at Buffalo, The State University of New York, a Member of Technical Staff at Bell Laboratories, Lucent Technologies, and a Senior Member of Technical Staff at Tyco Submarine Systems. She authored 7 invited book chapters and over 250 journal and conference research papers. She is a Fellow of the American Physical Society (APS), a Fellow of Optica (formerly the Optical Society of America), a Senior Member of the IEEE and SPIE, a co-Chair of CLEO Fundamental Science and SPIE Nanoscience and Engineering Applications conferences in 2021-2022.

Black Holes: Seeing the Unseeable

Black holes emit no light of their own, and absorb everything that crosses their event horizon. But they are not invisible, and thanks to some spectacular breakthroughs of recent years, now we can see them. I will tell the remarkable story of black hole imaging and explain the science in simple terms: What are we looking at in a black hole image, and what do we learn from it? I will also describe the exciting future of this new field, with new telescopes and space missions set to probe black holes in finer detail than ever before, putting our understanding of gravity to the ultimate test.

Bio: Prof. Gralla works in gravitational physics at the intersection of theory and experiment, with an emphasis on black holes. He is widely regarded as an effective public speaker, with his recorded lectures receiving hundreds of thousands of views online. https://youtu.be/Dn33_ySzB-w

The Physics of Active Matter

Birds flock, bees swarm and fish school. These are just some of the remarkable examples of collective behavior found in nature. Physicists have been able to capture some of this behavior by modeling organisms as ``flying spins’’ that align with their neighbors according to simple but noisy rules. Successes like these have spawned a field devoted to the physics of active matter – matter made not of atom and molecules but of entities that consume energy to generate their own motion and forces. Through interactions, collectives of such active particles organize in emergent structures on scales much larger than that of the individuals. There are many examples of this spontaneous organization in both the living and non-living worlds: motor proteins orchestrate the organization of genetic material inside cells, swarming bacteria self-organize into biofilms, epithelial cells migrate collectively to fill in wounds, engineered microswimmers self-assemble to form smart materials. In this lecture I will introduce the field of active matter and highlight ongoing efforts by physicists, biologists, engineers and mathematicians to model the complex behavior of these systems, with the goal of identifying universal principles.

ProgressTowards topological quantum computation using Majorana fermions 

Topology has turned into a guiding principle that is used to understand the properties of quantum many-body systems in condensed matter physics. One of the most tantalizing applications of these ideas that has been proposed so far is topological quantum computation, which uses topological principles to stabilize quantum degrees of freedom against environmental decoherence. I will start by reviewing briefly work that started during my postdoctoral research that led to the prediction of a platform for topological quantum computation (TQC) using Majorana modes in topological superconductors. The simplicity of this class of systems has resulted in several experimental attempts, which have successfully observed preliminary evidence for the Majorana zero modes in the form of nearly quantized zero-bias conductance peaks. The next step has proven more complicated, which is understood to be a result of competition from on-topological quasi-Majorana states. I will then summarize my recent work where we are trying to move this field forward by proposing systematic approaches to separate such false positives as well as identify issues such as disorder that maybe obstructing progress. These ideas are also finding application in other approaches to TQC involving new materials such as iron-based topological superconductors and quantum Hall/superconductor interfaces. The intense effort on what appears to be a long challenging path is worthy because TQC using topological superconductors is currently the only scalable proposal on the horizon for quantum computation.

How Quantum Mechanics Helps Identify Mechanisms and Discover Materials to Combat Climate Change

Each year that passes now brings more evidence that carbon dioxide and methane emissions are bringing our world closer to a tipping point beyond which it is unclear how humans and other living creatures will survive. I have been driven by this concern for the last 15 years. I decided a decade and a half ago to reorient all my research to work on sustainable energy solutions. I am a physical chemist by training, with expertise in quantum mechanics methods development and applications primarily related to materials science and chemistry. While I still work on sustainable energy, it is now evident that such solutions are not enough. We must stop emitting additional carbon into the atmosphere; we must go not just to zero but to negative emissions, in order to mitigate against worsening climate change caused by nearly a century and a half of fossil fuel extraction and burning. Thus, in addition to materials discovery for sustainable, carbon-free electricity (e.g., solar cells, fusion, solid oxide fuel cells), I work on catalyst discovery for renewable fuels, via (electro/solar thermo)-chemical water splitting and (photo/electro/solar thermo)-chemical carbon dioxide reduction. If we can produce liquid fuels from carbon dioxide and water – effectively running combustion backwards – via innovative catalysts that take in sunlight or carbon-free excess electricity, we will recycle carbon rather than extract and add more of it to the atmosphere and oceans. However, recycling carbon dioxide and methane is still not enough. We must convert and store carbon dioxide and methane permanently. Rather than focus on subsurface sequestration of carbon dioxide, let’s find more productive—and less risky—uses for CO₂. In this talk, I will describe research related to carbon cycling back to fuels and useful chemicals, along with a vision for getting to negative emissions enabled by electrocatalysis. These approaches, along with available and emerging strategies in agriculture, forestry, and construction materials, may let our grandchildren and their descendants still enjoy the world we have been lucky enough to inhabit up to now. I hope that my talk will inspire others to join the effort.

About the Speaker
Professor Emily Carter is a theorist/computational scientist first known in her independent career for her research combining ab initio quantum chemistry with molecular dynamics and kinetic Monte Carlo simulations, especially as applied to etching and growth of silicon. Later, she utilized quantum mechanics, applied mathematics, and solid state physics to construct a diverse set of advanced simulation methods based on quantum mechanics: (i) linear-scaling orbital-free, density-functional theory (OFDFT) that can simulate unprecedented numbers of atoms quantum mechanically; (ii) embedded correlated wavefunction theories that combine quantum chemistry with periodic DFT to compute accurately condensed matter ground and excited electronic states, charge-transfer phenomena, and strongly correlated materials (furnishing, e.g., the first ab initio view of the many-body Kondo state of condensed matter physics and treatment of charge transfer and excited states of adsorbates on surfaces important for photo/electrocatalysis), and (iii) fast algorithms for ab initio multi-reference correlated electronic wavefunction methods that permit accurate thermochemical kinetics and excited states to be predicted for large molecules. She was a pioneer in quantum-based multiscale simulations of materials that eliminate macroscopic empirical constitutive laws and that led to new insights into, e.g., shock Hugoniot behavior of iron and stress-corrosion cracking of steel. Earlier, her doctoral research furnished new understanding of homogeneous and heterogeneous catalysis, while her postdoctoral work presented the condensed matter simulation community with the widely used rare event sampling method known as the Blue Moon Ensemble. Her research into how materials fail due to chemical and mechanical effects furnished proposals for how to optimally protect these materials against failure (e.g., by doping, alloying, or coating). Her work, especially on optimizing thermal barrier coatings for jet turbine engines, unraveled long-standing mysteries as to the roles of various alloying elements in those coatings.

Her current research includes the development of efficient and accurate quantum mechanics simulation techniques such as her embedded correlated wave function theories and multi-level quantum simulation methods. She uses these techniques now mainly to elucidate mechanisms of photo- and electro-catalysis, aimed at discovery and design of optimal catalysts for carbon dioxide utilization and more recently solid sequestration, as could be enabled by excess renewable energy.

Theory and supercomputing advancing the search for new physics in neutron experiments

The standard model of particle physics explains almost all observations except that our universe exists; so, though it is immensely successful, it must be incomplete.  Apart from cosmological observations, experiments either at high-energy or with high precision can provide hints about the missing physics. Laboratory experiments with neutrons, nuclei, atoms and molecules have now reached the precision necessary to be complimentary to and competitive with high-energy accelerator experiments.  At the same time, it is only recently that computing power has been sufficient to allow one to carry out the corresponding theoretical calculations with sufficient precision.  We can, now, start to effectively combine the continually improving experimental limits with the required computations to constrain ideas about physics beyond the standard model that better fit our cosmological theories. I will discuss these exciting calculations, present some results, point to newly discovered issues, and mention ongoing developments aimed at solving them.

About the speaker:
Dr. Tanmoy Bhattacharya works in the fields of Lattice Quantum Chromodynamics (QCD) for high-energy and nuclear physics, fundamentals of quantum mechanics, quantum computation, computational approaches to evolutionary biology and linguistics, data science, machine learning and vaccine development. He attended the Indian Institute of Technology where he received a Bachelor of Science degree in 1982 and Master of Science degree in 1984. In 1989, Dr. Bhattacharya received his Doctorate of Philosophy in Physics from the Tata Institute of Fundamental Research. He then joined the Brookhaven National Laboratory at Brookhaven in Long Island as a postdoctoral fellow. After two years in Long Island, Dr. Bhattacharya moved to France to work at Service de Physique Theorique. In November 1992, he moved back to the United States to join the high-energy particle theory group at Los Alamos National Laboratory in New Mexico as a postdoc and in 1999 he became a regular staff member at Los Alamos Labs. Dr. Bhattacharya has made fundamental, important discoveries that have been widely employed; and become a recognized authority nationally and internationally in the fields of lattice QCD, evolutionary linguistics and computational biology.

Addressing Stress and Mental Health in Graduate Education

Our department makes stress and mental health a major point of attention for our graduate program. Our approach is not to lower the bar for the PhD degree. Instead, we strive to eliminate unnecessary sources of stress and create conditions in which students feel engaged, supported, and empowered. The key to our initiative lies in contributions from students, staff, faculty, and the university health services. While only professionals can provide therapy, three chemistry faculty members serve as Mental Health Advocates and help to direct faculty, staff, and students to relevant resources. Students formed the group Community of Chemistry Graduate Students (CCGS), which organizes regular events on physical and mental health and stress management. To reach out to students outside the department, the CCGS also prepared a range of insightful videos on the topics of mental health in graduate school, academic success, and the transition into a job after graduate school. CCGS representatives and the department also worked with university health services to develop biannual surveys that help us better understand sources of stress. The survey taught us a lot about our students and, within a relatively short time, allowed us to improve a range of graduate program procedures.

 

(1) Stress and mental health in graduate school: How student empowerment creates lasting change, Mousavi, M. P. S.; Sohrabpour, Z.; Anderson, E. L.; Stemig-Vindedahl, A.; Golden, D.; Christenson, G.; Lust, K.; Bühlmann, P. J. Chem. Ed. 2018, 95, 1939–1946. (2) https://sites.google.com/umn.edu/ccgs?pli=1

The Science of Sakharov

Andrei Sakharov's outstanding contribution covers a wide area of ​​applied and fundamental physics, despite the fact that he regretted that he was only doing great physics "on the sidelines". In 1950, Sakharov and Tamm came up with the concept of controlled fusion, which led to the major international ITER project under construction in France.

Then he took up the old important unsolved problem of matter distribution non-uniformities in the Universe and, as a solution, proposed that the remnants of quantum fluctuations in the early phases after the Big Bang play a key role.

Baryon asymmetry has been another grand challenge in which Sakharov's name has been known since 1967, when he published the famous three conditions that the basic laws of physics and cosmology must satisfy in order to explain the dominance of matter over antimatter in our Universe.

About the speaker:
Roald Sagdeev is a UMD Distinguished University Professor Emeritus. He earned his Ph.D. in 1966 from Moscow State University and served for 15 years as director of the Space Research Institute, the Moscow-based center of the Russian space exploration program, where he holds the title of director emeritus. Prior to his work with the Soviet space exploration program, he had a distinguished career in nuclear science with international recognition for his work on the behavior of hot plasma and controlled thermonuclear fusion. He is a member of the National Academy of Sciences, the Royal Swedish Academy, the Max Planck Society and the International Academy of Aeronautics. Sagdeev has received the American Astronautical Society's Carl Sagan Memorial Award, and the American Physical Society's James Clerk Maxwell Prize for Plasma Physics.

The future of particle physics at the energy frontier

The energy frontier in particle physics explores the TeV energy scales, with the ambitious goal to explore the unknown and answer several fundamental questions related to the evolution of the early universe, the matter-antimatter asymmetry, the nature of dark matter, the origin of neutrino masses, the origin of the electroweak scale and the origin of flavor. The energy frontier is at a turning point, in which experimental guidance is needed to shed light on new physics beyond the Standard Model. Collider physics can provide such guidance thanks to a uniquely broad range of phenomena that allows us to searches for new physics in a direct way and indirectly via precision measurements. While the discovery of the Higgs boson has completed the Standard Model, it has also provided a unique way to search for new physics, thanks to its intimate connections to the open big questions of particle physics. Severalcollider physics projects have been proposed to expand the precision physics program with the Higgs boson (e+e- Higgs factories), while multi-TeV colliders (hadron and muon colliders) have been proposed as the ultimate exploration machines. The recurring long-term planning exercise for the US particle physics community, also known as Snowmass, has completed its 2020-2022 process and final reports are being released. This physics-driven effort, open to the whole national and international high-energy physics community, has identified physics opportunities, developed short, medium and long-term physics aspirations and formulated sharp recommendations, which will be used by the “Particle Physics Project Prioritization Panel” - P5 - as input to define priorities for future US projects. During the Snowmass process new ideas and proposals have emerged as well as a renewed interest and ambition to bring back energy-frontier collider physics to the US soil. A common sentiment was expressed to start now preparations for the next collider experiments beyond the HL-LHC to maintain and strengthen the vitality and motivation of the community. This is an exiting time as we are shaping the future of particle physics for decades to come.

About the speaker: Alessandro Tricoli is a senior scientist at Brookhaven National Laboratory (BNL). Hegraduated from the University of Bologna, Italy, then moved to the U.K. for his PhD at the University of Oxford. He stayed in the UK as Research Associate at the Rutherford Appleton Laboratory (RAL), then he moved to CERN as Research Fellow and then Research Staff. He joined BNL in 2016. In 2017 he was awarded the U.S. DOE Early Career Award.
Alessandro was a member of the OPAL Collaboration at LEP and joined the ATLAS Collaboration at the LHC in 2002. In ATLAS he has worked on physics analyses on strong and electroweak interactions and has led several activities. Among them, he coordinated trigger groups on electron and photon signatures, trigger menu, and he was a Standard Model physics group convenor.

Nonequilibrium thermodynamic limits to fluctuations and response

 Thermodynamics is a remarkably successful theoretical framework, with wide ranging applications across the natural sciences. However, thermodynamics is limited to equilibrium or near-equilibrium situations, whereas most of the natural world, especially life, operates very far from equilibrium. Research in nonequilibrium statistical thermodynamics is beginning to shed light on this domain. In this talk, I will present two such recent predictions. The first is a bound that quantifies how dissipation shapes fluctuations far from equilibrium. Besides its intrinsic allure as a universal relation, I will discuss one possible application where it offers insight into optimal heat engine design. The second is a series of equalities and inequalities---akin to the Fluctuation-Dissipation theorem but valid arbitrarily far from equilibrium---that link a system’s sensitivity to the strength of nonequilibrium driving. I will discuss how these predictions rationalize known energetic requirements of some common biochemical motifs.

TBA

Machine Learning for Forecasting Complex Systems