Events at Physics
Events on Monday, February 5th, 2024
- Atomic Physics Seminar
- Novel strategies for hardware-efficient quantum processors
- Time: 12:00 pm - 1:00 pm
- Place: 5310 Chamberlin Hall
- Speaker: Harry Levine, AWS Center for Quantum Computing
- Abstract: Quantum error correction is an exciting scientific frontier at the interface of many fields including quantum information science, many-body physics, and computer science. The field has developed rapidly in the last several years, with major milestones marking the first glimpses into a future of error-corrected quantum computers. At the same time, these advances have also illuminated the major science and engineering challenges that remain on the road to useful fault-tolerant quantum computers due to large resource overheads and demanding performance and control requirements. In this talk, I will discuss recent progress in strategies to ease the demands of error correction with a focus on two leading quantum information platforms: superconducting circuits and cold atoms. First, I will discuss the paradigm of “erasure qubits” which are qubits for which errors can be flagged in real-time and are consequently easier to correct. In this context, I will discuss recent experiments showing how erasure qubits can be realized using a “dual-rail” encoding in superconducting transmons, offering a way to package standard qubit components into better error correction building blocks. Second, I will discuss the recent, rapid progress in neutral atom quantum computers and highlight how the unique capabilities for efficient and flexible control can ease the path towards scalable operation of error-corrected quantum processors. Finally, I will discuss prospects for next-generation neutral atom systems and applications in quantum error correction and precision measurement.
- Host: Thad Walker
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Magnetohydrodynamics of tokamak disruptions
- Time: 12:00 pm - 1:15 pm
- Place: 1227 Engineering Hall
- Speaker: Prof. Carl Sovinec, UW-Madison
- Abstract: Full-scale operation of the ITER experiment will produce plasma thermal energy and releasable magnetic energy on the order of hundreds of mega-Joules. Unplanned disruptions to these discharges will be capable of causing significant material damage to plasma-facing components and electrically conducting structures. As such, the susceptibility to disruptions poses the greatest challenge for the tokamak as a fusion reactor concept. In this presentation, operational limits and the typical sequence of dynamics during disruptions are reviewed, as is the physics behind localized heat deposition, electromechanical forcing, and runaway electron (RE) generation. Extended-magnetohydrodynamic (MHD) numerical simulations provide insight into the physics of tokamak disruptions. Results computed with the NIMROD code (nimrodteam.org) describe profile relaxation and surface-force densities during asymmetric vertical displacement. Other simulations show the importance of MHD for mitigation with massive gas injection and shattered pellet injection. The confinement of REs and their influence on MHD is also considered.
- Host: Prof. Carl Sovinec