Events at Physics |
Events During the Week of January 11th through January 18th, 2026
Monday, January 12th, 2026
- No events scheduled
Tuesday, January 13th, 2026
- Preliminary Exam
- Progress towards Quantum Error Correction (QEC) on Neutral atom quantum computing.
- Time: 10:30 am - 12:00 pm
- Place: Chamberlin Hall Room 5280
- Speaker: Linipun Phuttitarn
- Abstract: Quantum computers hold the promise of solving problems that are computationally intractable for classical computers. However, errors arising from interactions with the environment and imperfect control limit their computational power. Quantum error correction (QEC) addresses this challenge by detecting and correcting errors in logical qubits, which are encoded across multiple physical qubits. Implementing QEC, however, requires physical qubits with gate fidelities above a certain threshold and the ability to perform mid-circuit, qubit-selective measurements.
In this talk, I will present our progress toward implementing QEC on a neutral-atom quantum processor. First, I will describe a mid-circuit, qubit-selective measurement scheme using a single alkali species that exploits the hyperfine structure. Then, I will discuss a machine learning techniques to enhance qubit readout fidelity. I will also present our work on improving entangling gate fidelity using single-photon Rydberg excitation. Finally, I will outline our roadmap for achieving the QEC milestone on our processor. - Host: Mark Saffman
Wednesday, January 14th, 2026
- Preliminary Exam
- Tokamak Plasmas above Traditional Density Limits in the Madison Symmetric Torus
- Time: 1:00 pm - 3:00 pm
- Place: 5280 Chamberlin
- Speaker: Joseph Flahavan
- Abstract: Recent experiments in the Madison Symmetric Torus (MST) have demonstrated the capability of sustaining stable tokamak plasmas with densities far above the Greenwald limit, up to 18nG. The Greenwald limit, nG, is an empirically determined upper limit on the line-averaged electron density for stable operation of current-carrying toroidal laboratory plasmas, including tokamaks. Fusion power increases with density, making it of interest to determine the nature of MST’s ability to operate without disruptions at densities far greater than the conventional limit. When the electron density approaches 2nG, a distinct equilibrium develops with broadened electron density and nearly flat current density profiles. This happens to occur near the Sudo limit, nS, an empirical density limit observed in stellarators that is attributed to radiative collapse and is dependent on input power. Here, I present direct measurements, profile reconstructions, and fluctuation analysis across the range of densities that has been accessed in MST tokamak plasmas, 0.5 < ne/nG < 18, with a focus on plasmas near nG and nS where changes in behavior are observed. Experimental results are compared to several different theoretical models of the Greenwald density limit, including those involving enhanced edge turbulence or radiation-destabilized tearing modes.
- Host: John Sarff
Thursday, January 15th, 2026
- Graduate Program Event
- Physics Qualifying Exam - Classical Mechanics
- Time: 9:00 am - 10:30 am
- Place: 2241 Chamberlin
- Host: Sharon Kahn
- Graduate Program Event
- Physics Qualifying Exam - Statistical Mechanics
- Time: 11:30 am - 1:00 pm
- Place: 2241 Chamberlin
- Host: Sharon Kahn
- Preliminary Exam
- Kinetic impacts on Rayleigh-Taylor-driven magnetic reconnection in accretion flows
- Time: 2:30 pm - 4:30 pm
- Place: B343 Sterling or
- Speaker: Braden Buck, Physics PhD Graduate Student
- Abstract: The Rayleigh-Taylor instability (RTI) is ubiquitous in many fluid flows, such as astrophysical plasma flows. The RTI encourages mixing in a medium with an unstably stratified density profile under the influence of an accelerating force such as gravity. If a sheared magnetic field profile is present, the RTI can cause reconnection to occur through plasma mixing, leading to nonthermal particle acceleration for sufficiently low beta plasmas. While the kinetic effects of this phenomenon have been previously studied in two-dimensional simulations (V. Zhdankin, B. Ripperda, A. A. Philippov, 2023), three-dimensional effects have not been explored. Here, we directly compare two-dimensional and three-dimensional localized particle-in-cell kinetic simulations to elucidate three-dimensional effects on RTI-driven magnetic reconnection in a sub-relativistic pair-plasma subjected to a sheared magnetic field profile and RTI-unstable density stratification. This analysis is carried out for a parameter scan across magnetic shear angle values. We expect that these results can provide further insights into plasma physics governing reconnection as well as the near-infrared and X-ray flares observed from localized regions of the accretion disk surrounding Sagittarius A*.
- Host: Vladimir Zhdankin
- Notebook reclamation project
- Notebook reclamation project - January 2026 edition
- Time: 2:30 pm - 3:30 pm
- Place: 4328 Chamberlin
- Speaker: Sharon Kahn
- Abstract: A large number of lab notebooks are abandoned each semester by students in physics undergrad classes. Rather than leaving these to hit the garbage or collect dust in grad offices, help reclaim them!
1 – If you have abandoned notebooks in your office (whether from your students or notebooks that were there when you moved in!), bring them to 4328 CH by Thursday, January 15.
2 – Join us to help strip out and recycle the used pages (no need to sign up – just come help!):
3- Need a notebook? Reclaimed notebooks will be free for the taking in the CH lobby (next to the mural).
Friday, January 16th, 2026
- Graduate Program Event
- Physics Qualifying Exam - Electricity and Magnetism
- Time: 9:00 am - 10:30 am
- Place: 2241 Chamberlin
- Host: Sharon Kahn
- Graduate Program Event
- Physics Qualifying Exam - Quantum Mechanics
- Time: 11:30 am - 1:00 pm
- Place: 2241 Chamberlin
- Host: Sharon Kahn