Events at Physics |
Events During the Week of October 9th through October 16th, 2022
Monday, October 10th, 2022
- Plasma Theory Seminar
- Celebrating Women and Gender Diversity in Plasma Physics Seminar Series: Saskia Mordjick
- Time: 12:00 pm - 1:00 pm
- Place: 1610 Engineering Hall
- Speaker: Saskia Mordjick, College of William & Mary
- Abstract:
Fusion energy promises to produce clean and safe electricity on a large scale, but it still faces some challenges.). The fusion gain in a tokamak is directly linked to the density of the plasma. However, due to the high temperatures and densities, it impossible to fuel the plasma core in a fusion reactor, as all neutral particles will ionize at the edge of the device. Without any direct fueling in the core of a tokamak, the plasma density is fully controlled by transport perpendicular to the confining magnetic field surfaces. In this talk I will show how cross-field transport is dominated by turbulence in the plasma core by comparing experiments with existing models. These models capture how various types of turbulence influence transport and thus the density profile. While the density profile in the core is fully determined by turbulent transport, at the plasma edge, the picture is more complicated. At the edge of the tokamak, turbulent transport effects intermingle directly with fueling through ionization of the surrounding gas. Sustaining a high-density plasma, which is opaque to neutrals is not dissimilar to a minority navigating the fusion and plasma community. The talk will be interwoven with personal experiences, statistics and best practices to achieve a healthy fusion community and reduce the opaqueness for minorities to succeed. - Plasma Physics (Physics/ECE/NE 922) Seminar
- The plasma density as the main lever to controlling fusion reactors
- Time: 12:00 pm
- Place: 1610 Engineering Hall
- Speaker: Saskia Mordic, William & Mary
- Abstract: Fusion energy promises to produce clean and safe electricity on a large scale, but it still faces some challenges.). The fusion gain in a tokamak is directly linked to the density of the plasma. However, due to the high temperatures and densities, it impossible to fuel the plasma core in a fusion reactor, as all neutral particles will ionize at the edge of the device. Without any direct fueling in the core of a tokamak, the plasma density is fully controlled by transport perpendicular to the confining magnetic field surfaces. In this talk I will show how cross-field transport is dominated by turbulence in the plasma core by comparing experiments with existing models. These models capture how various types of turbulence influence transport and thus the density profile. While the density profile in the core is fully determined by turbulent transport, at the plasma edge, the picture is more complicated. At the edge of the tokamak, turbulent transport effects intermingle directly with fueling through ionization of the surrounding gas. Sustaining a high-density plasma, which is opaque to neutrals is not dissimilar to a minority navigating the fusion and plasma community. The talk will be interwoven with personal experiences, statistics and best practices to achieve a healthy fusion community and reduce the opaqueness for minorities to succeed.
Tuesday, October 11th, 2022
- Network in Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Seminar
- New Insights Into Lepton-Axion Interactions
- Time: 2:00 pm
- Place: Join Zoom Meeting Meeting ID: 912 3071 4547
- Speaker: Jeff Dror , UCSC
- Abstract: Axion-like particles (ALPs) below the electroweak scale are a simple, natural extension to the Standard Model and, as such, are one of the primary targets for the large-scale experimental effort to search for hidden sectors. In this talk, I revisit the theoretical framework of ALP interactions with leptons, finding some unexpected features in some amplitudes. Most importantly, I will show that there exist strong bounds on "leptophilic" ALPs from a combination of charged meson decays, W boson measurements, and proton beam dump experiments. These bounds dramatically shape allowed ALP parameter space and will be significantly improved with dedicated searches.
Join Zoom Meeting
Meeting ID: 912 3071 4547
- Host: Baha Balantekin
- Council Meeting
- Time: 3:00 pm - 4:00 pm
- Place: 5290 Chamberlin Hall
- Speaker: Mark Eriksson, UW-Physics
- Host: Mark Eriksson
- Theory Seminar (High Energy/Cosmology)
- Over-Extremal Brane Shells from String Theory
- Time: 4:00 pm - 5:00 pm
- Place: Chamberlin 5280
- Speaker: Vincent Van Hemelryck, Leuven U.
- Abstract: In this talk, I will argue that there must exist spherical brane shells in 4d that are overcharged, if the usual phenomenological compactifications of type IIB string theory with warped throats and anti-branes make sense. These shells correspond to classical over-extremal objects but without the usual naked singularities. The objects are made from D3-particles that puff into spherical 5-branes that stabilise at finite radii in 4d and whose inside corresponds to the supersymmetric AdS vacuum. We find that these objects can be significantly larger than the string scale depending on the details of the warped compactification.
- Host: George Wojcik
Wednesday, October 12th, 2022
- Department Meeting
- Time: 12:15 pm - 1:00 pm
- Place: B343 Sterling Hall
- Speaker: Mark Eriksson, UW-Madison, Physics
- Monthly Department Meeting
- Host: Mark Eriksson
Thursday, October 13th, 2022
- R. G. Herb Condensed Matter Seminar
- Measurement-induced Phase Transitions in the Dynamics of Quantum Entanglement
- Time: 11:00 am - 6:00 pm
- Place: 5310 Chamberlin
- Speaker: Brian Skinner , Ohio State University
- Abstract: When a quantum system evolves under unitary dynamics, as produced by either a Hamiltonian or by a sequence of gates inside a quantum computer, its various component parts tend to become more entangled with each other. Making measurements, on the other hand, tends to reduce this entanglement by collapsing some of the system's degrees of freedom. In this talk I'll consider what happens to the entanglement when a quantum many-body system undergoes both unitary evolution and sporadic measurements. I'll show that the competition between these two effects leads to a new kind of dynamical phase transition, such that when the measurement rate is lower than a critical value the dynamics is "entangling", while a higher-than-critical measurement rate leads to a "disentangling" phase. I will discuss our work demonstrating the existence of this transition, as well as more recent efforts to find exact solutions for its critical properties. I will show how intuition from classical percolation in disordered conductors played a key role in our understanding of the transition.
- Host: Alex Levchenko
- Astronomy Colloquium
- The Smallest and Faintest Galaxies: Clues to the Nature of Dark Matter and Galaxy Formation
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall, Or via zoom
- Speaker: Burçin Mutlu-Pakdil, Dartmouth University
- Abstract: The smallest and faintest galaxies around the Milky Way are the most ancient, most metal-poor, and most dark-matter-dominated systems known. These extreme objects offer unique access to small scales where the stellar and dark matter content can be studied simultaneously. They hold the promise of major breakthroughs in understanding the nature of dark matter and a more complete picture of galaxy formation. Thus, their discovery and characterization are among the most important goals in the field. In this talk, I will share our ongoing observational efforts to detect these faint systems around the Milky Way and beyond, and upcoming advances in the era of deep and wide imaging instrumentation, with a focus on their implications.
- Wisconsin Quantum Institute
- Quantum Nanophotonics Hardware: From Nanofabrication to Quantum Circuit Mapping
- Time: 4:00 pm - 5:00 pm
- Place: MS&E Building room 265
- Speaker: Marina Radulaski, Department of Electrical and Computer Engineering University of California - Davis
- Abstract: Photonic systems are the leading candidates for deterministic quantum sources, quantum repeaters, and other key devices for quantum information processing. Scalability of this technology depends on the stability, homogeneity and coherence properties of quantum emitters. Here, color centers in wide band gap materials offer favorable properties for applications in quantum memories, single-photon sources, quantum sensors, and spin-photon interfaces [1,2]. Silicon carbide, in particular, has been an attractive commercial host of color centers featuring fiber-compatible single photon emission, long spincoherence times and nonlinear optical properties [3]. Integration of color centers with nanophotonic devices has been a challenging task, but significant progress has been made with demonstrations up to 120-fold resonant emission enhancement of emitters embedded in photonic crystal cavities [4]. A novel direction in overcoming the integration challenge has been the development of triangular photonic devices, recently shown to preserve millisecond-scale spin-coherence in silicon carbide defects [5,6]. Triangular photonics has promising applications in quantum networks, integrated quantum circuits, and quantum simulation. Here, open quantum system modeling provides insights into polaritonic physics achievable with realistic device parameters through evaluation of cavity-protection, localization and phase transition effects [7]. Mapping of this dynamic to gate-based quantum circuits opens doors for quantum advantage in understanding cavity quantum electrodynamical (QED) effects using commercial Noisy Intermediate-Scale Quantum (NISQ) hardware [8].
- Host: Mikhail Kats
Friday, October 14th, 2022
- Physics Department Colloquium
- Climate Change: Science, Technology and Policy
- Time: 3:30 pm - 6:00 pm
- Place: 2241 Chamberlin Hall
- Speaker: George Crabtree
- Abstract: Climate change is among the most important global challenges of the 21st century, affecting nearly every aspect of society including public health, food production, supply chains, inflation, financial/economic risk, human migration and geopolitics. National competitiveness and environmental justice for traditionally underserved communities are rapidly growing additional concerns. Responses to climate change include decarbonization to avoid its worst consequences, resilience to minimize its impact and adaptation to accommodate unavoidable change. These responses can be implemented through technology, policy and cultural change. Each of these options will be considered and put into perspective.
- Host: Uwe Bergmann
- Wonders of Physics
- Science on the Square
- Time: 4:00 pm - 8:00 pm
- Place: State Street
- Speaker: various, Dept of Physics
- Abstract: Join the Department of Physics and scientists from around UW and Madison at Science on the Square! Held from 4-8pm Friday, Oct 14, you can see two Wonders of Physics live shows at the top of State Street. WIPAC, GMaWiP, and others will be hosting activity tables along State Street as well.
This event is held as part of WiSciFest and is being held in conjunction with the Madison Night Market. Visit for full details - Host: WiSciFest