Events at Physics |
Events During the Week of April 21st through April 28th, 2024
Monday, April 22nd, 2024
- Plasma Physics (Physics/ECE/NE 922) Seminar
- "Advancing Fusion Research through Virtual Design"
- Time: 12:00 pm - 1:15 pm
- Place: 1227 Engineering Hall
- Speaker: Frank Jenko, IPP
- Abstract: Tackling the Grand Challenge of understanding, predicting, and managing turbulent transport remains critical in fusion research. Nonlinear gyrokinetic simulations are paramount for precise and dependable forecasts. Recent breakthroughs now permit whole-device modeling, extending from the magnetic axis to the material walls. Additionally, the adoption of code coupling techniques has notably expedited the profile prediction process for large fusion devices like ITER. Concurrently, a suite of multi-fidelity techniques are in development, which promise to drastically cut down computational requirements by several magnitudes, allowing for the development of flight simulators and potentially reaching real-time control capabilities. Utilizing these strategies paves the way for optimizing the design of future fusion power plants, thereby propelling the field of fusion research forward.
- Host: Prof. Carl Sovinec
- Department Meeting
- CLOSED department meeting
- Time: 12:15 pm - 1:15 pm
- Place: B343 Sterling Hall
- Speaker: Mark Eriksson
- Closed meeting to discuss personnel matters—pursuant to Section 19.85(1)(c) of the Wisconsin Open Meetings Law
- Host: Mark Eriksson
Tuesday, April 23rd, 2024
- Preliminary Exam
- Nonlocal transport effects in electron bilayers
- Time: 12:00 pm - 2:00 pm
- Place: 5280 Chamberlin
- Speaker: Dmitry Zverevich, Physics Graduate Student
- Abstract: With the discoveries of novel materials, efforts are underway to create hybrid multilayers by stacking them together to form complex heterostructures and to explore new emergent fundamental physics governed by electron correlations. Experimental results on drag resistivity between quantum wires and double-layer graphene heterostructures triggered theoretical works, including new proposals for the mechanisms of this phenomenon. I am going to talk about the predictive theory of Coulomb drag and its relative phenomenon of near-field heat transfer in the context of correlated electron phases and investigate unexplored regimes of quantum transport in various mesoscale systems.
- Host: Alex Levchenko
- Council Meeting
- Physics Council Meeting
- Time: 3:00 pm - 4:00 pm
- Place: 2314 Chamberlin
- Speaker: Mark Eriksson, UW - Madison
- Host: Mark Eriksson
- Network in Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Seminar
- Microscopic calculations of neutrino scattering and absorption in warm dense nuclear matter
- Time: 6:00 pm - 6:00 pm
- Place: Join Zoom Meeting Meeting ID: 912 3071 4547
- Speaker: Prof. Jeremy Holt , Texas A&M University
- Abstract: Numerical simulations of core-collapse supernovae, proto-neutron star cooling, and neutron star mergers require modeling of neutrino scattering and reaction rates that are sensitive to medium effects, including nuclear mean fields and correlations. In the past, it has been found that nuclear mean fields play an especially important role for enhancing electron-neutrino absorption and suppressing antineutrino absorption in warm and neutron-rich nuclear matter. In the present study, we investigate nuclear correlations on equal footing to mean fields through the random phase approximation (RPA) computed from microscopic models of the nucleon-nucleon interaction derived from chiral effective field theory. We find that RPA calculations generically indicate the presence of nuclear collective modes, which at low neutrino energies tend to suppress neutrino absorption and enhance antineutrino absorption, opposite to the effect of mean fields. We conclude that nuclear correlations should be treated on a consistent footing with mean fields in deriving neutrino charged-current reaction cross sections for astrophysical simulations.
Topic: N3AS online seminar series - Spring 2024 #7
NOTE: All participants and hosts are now required to sign into a Zoom account prior to joining meetings hosted by UC Berkeley.
PLEASE NOTE THE UNUSUAL TIME. - Host: Baha Balantekin
Wednesday, April 24th, 2024
- Department Meeting
- Time: 12:15 pm - 1:15 pm
- Place: B343 Sterling Hall
- Speaker: Mark Eriksson, UW - Madison
- Host: Mark Eriksson
- Preliminary Exam
- Scaling Technologies for Si/SiGe Quantum Dot Qubits
- Time: 2:00 pm
- Place: 5310 Chamberlin
- Speaker: Michael Wolfe, Physics Graduate Student
- Abstract: In this talk, I will discuss several solutions to the scale-up problem for solid-state quantum computers. This work focuses on semiconductor quantum-dot qubits in Si/SiGe, which share material compatibility with the existing microprocessor industry. I will show how to leverage this compatibility through the fabrication of a classical on-chip multiplexer to reduce the number of wires needed to control an array of Si/SiGe quantum devices. I will demonstrate the power of the multiplexer by performing rapid device diagnostics across the device array, and discuss pathways to scale up a quantum processor by deploying this technology for multiplexed readout. Next, I will show how to control in-situ the threshold voltages of Si/SiGe devices using cryogenic illumination. This technique rearranges the trapped charge at the oxide-semiconductor interface, in turn improving the uniformity of the operating voltages of Si/SiGe devices which can greatly simplifying the operation of large arrays of quantum dot qubits.
- Host: Mark Eriksson
Thursday, April 25th, 2024
- R. G. Herb Condensed Matter Seminar
- Title to be announced
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Peter Schmelcher, U Hamburg
- Host: Mark Saffman
- Preliminary Exam
- Progress towards cooling and imaging on an alkali atom forbidden transition
- Time: 11:00 am - 1:00 pm
- Place: Sterling Hall B343
- Speaker: Jacob Scott, Physics PhD Graduate Student
- Abstract: I present progress towards atomic manipulation on the 6S1/2 - 5D5/2 forbidden transition in Cs. I discuss a few intriguing features of this transition, including a very high pump-depump ratio, very low Doppler temperature, and an intermediate state that allows for background free imaging. I also discuss development of the experimental apparatus and preliminary results of the experiment.
- Host: Mark Saffman
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- NOvA Cross-section Measurement of Muon Antineutrino Charge Current Inclusive Interactions
- Time: 3:30 pm - 4:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Prabhjot Singh, Queen Mary University of London
- Abstract: Neutrino-nucleus interactions are one of the major systematics in neutrino oscillation experiments. In this high-precision era of neutrino oscillation measurements, the neutrino oscillation experiments need to have a good understanding of neutrino-nucleus interactions to reduce uncertainties in the oscillation measurements. NOvA is a long-baseline accelerator-based internationally-collaborated neutrino experiment based in the USA. NOvA uses an intense neutrino beam produced at Fermilab’s accelerator complex to make physics measurements of neutrino oscillations, neutrino cross sections, and other exotic and beyond the Standard Model neutrino analyses. For its physics goals, NOvA uses two functionally identical detectors. The Near Detector (ND) is situated at Fermilab, 1 km from the neutrino target and the Far Detector (FD) is located at Ash River, MN, 810 km from the neutrino source. The ND sees a high intensity of the neutrino beam due to its proximity to the neutrino target. This gives us a unique opportunity for high-precision neutrino cross-section measurements. In this seminar, we will talk about the motivations for doing neutrino cross-section measurements. We will also discuss different aspects of the NOvA experiment, and detectors. Finally, we present our latest muon antineutrino charge current inclusive cross-section measurement results in the NOvA ND. The new measurement is a triple differential cross section in antimuon kinematic phase-space and in the total energy of all observable final state hadrons, also known as the available energy. We also compare our data results to various neutrino generator predictions, for example, comparisons to GENIE, NuWro, NEUT, and GiBUU neutrino generators are presented.
- Host: Brian Rebel
- Astronomy Colloquium
- Goodbye to “Chi-by-Eye” : Results from a Bayesian Analysis of Photometric Binaries in Open Clusters
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Aaron M Geller, Northwestern University
- Abstract: Binary and higher-order multiple stars are ubiquitous, and their evolution can be dramatically influenced by their environment. Binaries in the field evolve essentially in isolation, while those within star clusters may experience frequent close stellar encounters that can significantly modify, and even disrupt, their orbits. Most stars like our Sun are believed to be born in star clusters, many of which dissolve to populate the field. Therefore, our interpretation of the observed binary populations in star clusters and the field (and even to some extent our understanding of star formation), relies on how a population of stars evolves through this more dynamically active stage in a star cluster. In this talk, I will provide an overview of the work my team and collaborators are pursuing to identify and analyze photometric binaries in galactic open clusters, in order to test predictions of star cluster models and learn about the dynamical state of our galactic open cluster population.
- Host: Ke Zhang
Friday, April 26th, 2024
- Physics Department Colloquium
- Structure and Dynamics from Random Observations
- Time: 3:30 pm - 5:00 pm
- Place: Chamberlin 2241
- Speaker: Abbas Ourmazd, University of Wisconsin-Milwaukee
- Abstract: Don’t be a control freak. At weddings, the bridal photo is taken under bright lights, with the happy couple holding still. Traditionally in science, the “best” observations are those with the largest signal from the most tightly controlled system. Like bridal photos, the results are not always exciting. In a wide range of phenomena – from the dance of proteins during their function, to the breaking of molecular bonds on the femtosecond scale – tight control is neither possible, nor desirable. Modern data-analytical techniques extract far more information from random sightings than usually obtained from set-piece experiments. I will describe on-going efforts to extract structural and dynamical information from noisy, random snapshots. Examples will include YouTube videos, the structure and conformations of molecular machines such as the ribosome, and the ultrafast dynamics of bond-breaking in small molecules like nitrogen. Less can be more, but only if there is plenty of it.
- Host: Uwe Bergmann