Events at Physics |
Events During the Week of February 2nd through February 9th, 2025
Monday, February 3rd, 2025
- Atomic Physics Seminar
- Emergent collective phenomena in macroscopic and mesoscopic systems
- Time: 11:00 am - 12:00 pm
- Place: 5310 Chamberlin
- Speaker: Dr. Zhenjie Yan, Univ. California Berkeley
- Abstract: From the persistent electric currents in superconductors to the synchronized motion of a flock of birds, emergent collective behaviors arise ubiquitously from the interactions between constituents in many-body ensembles. Ultracold atom experiments, with their precisely tunable interactions and well-controlled initial states, provide a powerful platform to explore these cooperative phenomena in quantum many-body systems. In this talk, I will present examples of collective effects in both macroscopic and mesoscopic regimes, drawn from my recent works. First, I will discuss thermal transport in a macroscopic strongly interacting Fermi gas, a system that poses significant challenges for existing theoretical and computational methods. The heat transport reveals a striking signature of a superfluid phase transition: while heat propagates diffusively in the normal phase, it propagates as a wave—known as second sound—below the superfluid transition temperature. Next, I will introduce recent work on constructing a mesoscopic system atom-by-atom using optical tweezers, with precise control over interactions mediated by photon exchange in an optical cavity. This platform enables the study of self-organization and symmetry breaking. The atom array reveals distinctive hallmarks of mesoscopic physics, such as the dependence of the critical point and the state lifetime on the system size. Finally, I will briefly outline my future research plans to develop quantum systems that are robust against noise and decoherence using atoms and light for emulating many-body systems and carrying out computational tasks.
- Host: Mark Saffman
- Plasma Physics (Physics/ECE/NE 922) Seminar
- "Learning magnetic field structure from trajectories"
- Time: 12:00 pm - 1:15 pm
- Place: 1227 Engineering Hall
- Speaker: David Bindel, Cornell University
- Abstract: The magnetic fields in stellarators can be organized into different regions according to the dynamics of field line flows, with regions of nested flux surfaces potentially interspersed with islands or regions of chaos. While can visualize these structures with Poincare plots, such visualizations are not wholly satisfactory if we wish to numerically optimize such structures. In this talk, we describe an approach to automatically inferring the structure of magnetic field line flows by building models of the dynamics of field line trajectories with connections to dynamical systems theory, numerical extrapolation methods, and the theory of adaptive filtering.
Joint work with Max Ruth (UT Austin). - Host: Prof. Adelle Wright
Tuesday, February 4th, 2025
- Thesis Defense
- Novel Quantum Devices for Computation and Sensing
- Time: 9:00 am - 11:00 am
- Place: 5310 CH
- Speaker: Abigail Shearrow, Physics PhD student
- Abstract: Josephson junction-based devices have demonstrated utility in a breadth of applications ranging from quantum computation to sensing and meteorology. In this talk we introduce two novel superconducting devices: a protected qubit relying on engineered composite Josephson elements and a mm-wave detector utilizing a Josephson junction for impedance matching to free space to enhance power absorption efficiency. First we introduce a novel quantum sensor, consisting of impedance-matched Josephson junction-based slot antennas embedded in a microwave kinetic inductance detector. We discuss operating principles and design of such devices. We present data on the response of devices to a thermal quasiparticle distribution and the calibration of the detector using a blackbody source. And finally spectroscopic characterization of the devices with a Josephson emitter. In the second part of this thesis we describe work toward the design, control, and characterization of a novel protected qubit, the charge-parity qubit, consisting of a composite pi-periodic Josephson element shunted by a large capacitance. Such a device provides protection against local noise at the hardware level and aspires to substantially reduce the overhead needed for quantum error correction. Together these projects demonstrate the versatility the Josephson junction in superconducting quantum devices.
- Host: Robert McDermott
Wednesday, February 5th, 2025
- Preliminary Exam
- Search for New Physics Phenomenon via Higgs Boson Pair Production and Novel Machine Learning Methods
- Time: 3:00 pm
- Place:
- Speaker: Chi Lung Cheng, Physics PhD student
- Abstract: Abstract 1: Search for New Physics via Higgs Boson Pair Production Higgs boson pair production provides a direct probe of the Higgs self-coupling and potential physics beyond the Standard Model (BSM). This study explores non-resonant HH production, focusing on constraints from collider data and theoretical models. Key results highlight the sensitivity of current and future experiments to BSM phenomena through precise measurements of the HH production cross-section and kinematic distributions.
Abstract 2: Novel Machine Learning Methods in High-Energy Physics This work introduces innovative semi-weakly supervised machine learning techniques for enhancing sensitivity to rare physics processes in collider experiments. By leveraging neural networks tailored to domain-specific features, the approach improves signal extraction and classification efficiency. Applications to simulated and real data demonstrate the effectiveness of these methods in uncovering subtle signatures of new physics phenomena. - Host: Sau Lan Wu
Thursday, February 6th, 2025
- R. G. Herb Condensed Matter Seminar
- Probing and controlling 2D magnets through the lens of quantum sensors
- Time: 10:00 am - 6:00 pm
- Place: 5310 Chamberlin
- Speaker: Brian Zhou, Boston College
- Abstract: Recently, the single electron spin of a defect in diamond known as the nitrogen-vacancy (NV) center has emerged as a versatile nanoscale magnetometer capable of operation in extreme environments and at diverse interfaces. In this seminar, I will highlight my group’s efforts to leverage NV quantum sensing for the high resolution imaging and detection of dynamical magnetization responses in 2D layered magnetic materials, which are difficult to probe by alternative techniques. We introduce novel quantum-enabled protocols to measure the ac magnetic susceptibility and optically-induced magnetization dynamics in atomically thin magnets. Moreover, we demonstrate the switching and detection of antiphase even-layer states in a 2D A-type antiferromagnet. This control over antiferromagnetic domains enables multilevel exchange bias on connected ferromagnetic-like regions through lateral exchange coupling. NV quantum sensors thus open a unique lens for understanding and controlling 2D magnetism for spintronic technologies.
- Host: Tiancheng Song
- Atomic Physics Seminar
- Adventures in optical clocks: quantum engineering, fundamental physics, and new frontiers
- Time: 11:00 am - 12:00 pm
- Place: 5310 Chamberlin
- Speaker: Dr. Tobias Bothwell, NIST Boulder
- Abstract: Optical atomic clocks are exemplary quantum sensors, combining robust environmental decoupling with exquisite laser phase sensitivity. By leveraging new quantum engineering techniques, today’s optical clocks now realize a staggering 19 digits of accuracy and precision. Beyond timekeeping, this new level of performance promises novel tests of fundamental physics, from general relativity to dark matter. Motivated by these advances, I will show how carefully controlling ensembles of neutral atoms tightly confined within optical lattices continues to push the limits of frequency metrology. I will first introduce optical lattice clocks (OLCs), which set precision records by leveraging thousands of trapped alkaline-earth-like atoms. Using strontium in a shallow lattice regime allows us to control atomic interactions and realize unprecedented measurement capability, resolving the gravitational redshift within our millimeter-scale atomic sample. In ytterbium we have developed and employed multiple ultracold ensembles within a standard OLC to measure accuracy-limiting differential atomic polarizabilities. Recently we have even operated OLCs outside the lab, with plans for measuring gravitational redshifts atop nearby mountains. Looking forward, the OLC architecture can be extended beyond alkaline-earth-like atoms, enabling a single-species clock network to explore new frontiers in both quantum metrology and fundamental physics.
- Host: Mark Saffman
- Astronomy Colloquium
- Inside NASA Communication: Incredible Science, Excruciating Suspense, SMH SNAFU’s and the Challenge of Communicating it All
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Dr. Michelle Thaller, NASA
- Abstract: I have been involved in communication for everything from our Mars missions to Climate measurements to JWST. How do you talk about the search for life without attracting tabloid headlines (I failed at that one)? What can you do to get the public excited about a very focused experiment that is yielding astonishing but obscure results? We’ll look at some amazing science results -hopefully some that you’ve never heard of before, and take a look behind the scenes of NASA science communication.
- Host: Melinda Soares-Furtado
Friday, February 7th, 2025
- Black and Brown in Physics
- General Meeting
- Time: 1:00 pm - 2:00 pm
- Place: Sterling B343
- Abstract: The Black and Brown in Physics (BBiP) student organization would like to invite you to our first General Meeting of the Spring 2025 semester! It will take place this upcoming Friday (2/7) from 1-2 PM in Sterling B343. Everyone is invited! We will have snacks! In honor of February being Black History month, and in light of recent events, we plan to dedicate this meeting to talk about the history of black education, and white supremacy in physics. We will follow this up with smaller group discussions on individual experiences, and ways to be more accountable/actionable when it comes to combating racism within our communities. However, dedicating a single meeting/discussion on this will not enough to solve all problems, which is why we will focus on brainstorming and setting more long-term goals for ourselves to create impactful change. We hope that you can join us!
- Host: Black and Brown in Physics
- Physics Department Colloquium
- Entanglement of Astrophysical Neutrinos - APS Bethe Prize Talk
- Time: 3:30 pm - 4:30 pm
- Place: 2241 CH
- Speaker: Prof. Baha Balantekin, University of Wisconsin-Madison
- Host: Mark Saffman
- Astronomy Colloquium
- Science Communication Talk
- Science Communication: It's Not About You.
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Dr. Michelle Thaller, NASA
- Abstract: One of the biggest challenges I have faced in developing scientists to be good (effective) communicators is getting them out of their own heads and back into the real world. The first question we begin with is, "are you honestly interested in communicating your science, or is this really about something you need to prove about yourself?" Whether it's a public talk, a mission proposal, or a conference session, there are techniques that can help you make a connection to your audience -practices that we know work. It isn't even all that difficult, but it requires stepping outside the established culture of science.
- Host: Melinda Soares-Furtado
Saturday, February 8th, 2025
- Wonders of Physics
- The Wonders of Physics 42nd annual show
- Time: 1:00 pm - 2:15 pm
- Place: 2103 Chamberlin
- Abstract: Fun, fast-paced, family-friendly physics demonstration show
- Host: Haddie McLean
- Wonders of Physics
- The Wonders of Physics 42nd annual show
- Time: 4:00 pm - 5:15 pm
- Place: 2103 Chamberlin
- Abstract: Fun, fast-paced, family-friendly physics demonstration show
- Host: Haddie McLean
Sunday, February 9th, 2025
- Wonders of Physics
- The Wonders of Physics 42nd annual show
- Time: 1:00 pm - 2:15 pm
- Place: 2103 Chamberlin
- Abstract: Fun, fast-paced, family-friendly physics demonstration show
- Host: Haddie McLean
- Wonders of Physics
- The Wonders of Physics 42nd annual show
- Time: 4:00 pm - 5:15 pm
- Place: 2103 Chamberlin
- Abstract: Fun, fast-paced, family-friendly physics demonstration show
- Host: Haddie McLean
