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Data: 2021-09-29 14:00

 

We kindly invite you to a webinar - Non-Hermitian spin-orbit-coupled quantum gases

Speaker: Gyu-Boong Jo (Department of Physics, HKUST)

Date and time: Wednesday, 29 September 2021, 14:00 Vilnius time

Location: MSTeams meeting (link below)

While spin-orbit coupling (SOC), an essential mechanism underlying quantum phenomena from the spin Hall effect to topological insulators, has been widely studied in well-isolated Hermitian systems, much less is known when the dissipation plays a major role in spin-orbit-coupled quantum systems. I will report the realization of the non-Hermitian spin-orbit-coupled quantum gases and observation of a parity-time (PT ) symmetry- breaking transition as a result of the competition between SOC and dissipation. In our experiment, tunable dissipation, introduced by state-selective atom loss, enables the energy gap, opened by SOC, to be engineered and closed at the critical dissipation value, the so-called exceptional point (EP) . The realized EP of the non-Hermitian band structure exhibits chiral response when the quantum state changes near the EP. This topological feature enables us to tune SOC and dissipation dynamically in the parameter space, and observe the state evolution is direction- dependent near the EP, revealing chiral spin transfer between different quantum states when the quantum state encircles the EP. This topological control of quantum state for non-Hermitian fermions provides new methods of quantum control, and also sets the stage for exploring non-Hermitian topological states with SOC.
More details are available in a recent article: https://arxiv.org/abs/2106.04874
 
MSTeams link:
https://teams.microsoft.com/l/channel/19%3a95ac9712144e4ab6b0c1040404c7dc84%40thread.tacv2/General?groupId=2feb718a-6943-4d00-98f4-c39354a50253&tenantId=82c51a82-548d-43ca-bcf9-bf4b7eb1d012
Passcode: 1wd20v6

Data: 2021-11-05 10:00

Vilniaus universiteto doktorantas Saulius Pakalka 2021 m. lapkričio mėn. 5 d., 10 val. A101 auditorijoje Nacionaliniame fizinių ir technologijų mokslų centre, Saulėtekio al. 3, LT-10257, Vilnius, gins gamtos mokslų srities Fizikos N 002 krypties disertaciją „Tiesioginės ir netiesioginės viengubos jonizacijos elektronų smūgiais tyrimas“ (“Theoretical study of direct and indirect single ionization by electron impact”). Vadovas: doc. dr. Valdas Jonauskas.

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