Graduate Program Events |
Events During the Week of April 27th through May 4th, 2025
Monday, April 28th, 2025
- No events scheduled
Tuesday, April 29th, 2025
- Mental Health for Graduate Students - Part 3 (of 3)
- Conflict Resolution
- Time: 4:00 pm - 5:00 pm
- Place: B343 Sterling
- Speaker: Neeti Shenoy, MA, and felix savino, Staff Psychologist, Mental Health Services/University Health Services
- Abstract: Join Neeti Shenoy, MA, and felix savino, Staff Psychologist, Associate Director and Training Director at MHS, for a discussion of strategies for resolving conflicts.
- Host: Sharon Kahn
Wednesday, April 30th, 2025
- No events scheduled
Thursday, May 1st, 2025
- No events scheduled
Friday, May 2nd, 2025
- Academic Calendar
- Last Spring Semester class day
- Abstract: *Note: actual end time may vary.*
- Thesis Defense
- Superconducting diode effect
- Time: 2:15 pm - 3:45 pm
- Place: 2104 CH
- Speaker: Jaglul Hasan, Physics PhD student
- Abstract: In this thesis, we explore the generalities of the supercurrent diode effect. As an illustrative example, we examine a model of a two-dimensional superconductor with Rashba-type spin-orbit coupling under an in-plane magnetic field and in the clean limit, which realizes a helical phase. First, we utilize Ginzburg-Landau phenomenology to derive a general formula for the diode efficiency. This is achieved by incorporating higher gradient terms in the Lifshitz invariants, which are responsible for the nonreciprocal superflow. Subsequently, we validate these results through microscopic diagrammatic computation and further estimate correction terms arising from interband pairing correlations. We provide a detailed comparison to prior investigations of this problem conducted within the framework of the quasiclassical approximation based on the Eilenberger equation.
Even though superconducting diode effect (SDE) has garnered significant attention due to its potential applications in superconducting electronics, the role of disorder scattering in SDE has rarely been considered, despite its potential qualitative impact, as we demonstrate. We investigate SDE in a disordered Rashba superconductor under an in-plane magnetic field, employing a self-consistent Born approximation to derive the corresponding Ginzburg-Landau theory. Our analysis reveals two surprising effects. First, in the strong Rashba SOC regime, disorder becomes the driving mechanism of SDE, which vanishes in its absence. In this case, we show that disorder-induced mixing of singlet and triplet superconducting orders underlies the effect. Second, in the weak Rashba spin-orbit coupling (SOC) regime, disorder can reverse the direction of the diode effect, indicated by a sign change in the superconducting diode efficiency coefficient. - Host: Alex Levchenko
Saturday, May 3rd, 2025
- Academic Calendar
- Study Day
- Abstract: *Note: actual end time may vary.*
Sunday, May 4th, 2025
- Academic Calendar
- Exams
- Abstract: *Note: actual end time may vary.*