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Public Seminar of RPg Student:
Quantum Spin Dynamics in a Spin-orbit Coupled Bose Gas


Speaker:Mr. Wai Ho TANG
Affiliation:The University of Hong Kong
Date:September 21, 2017 (Thursday)
Time:2:15 p.m.
Venue:Rm 518, 5/F, Chong Yuet Ming Physics Building, HKU

Abstract
 

Spin-orbit coupling (SOC) has given rise to many novel features of physical systems, from single atom to solid materials. Since its recent experimental realisation in neutral atoms, many theoretical and experimental studies have revealed new phases and properties of Bose condensate with SOC. On the other hand, little attention has been paid to the effects of spin-orbit interaction in thermal Bose vapour with SOC. In this study, we derive transport equations governing the spin dynamics of a two-component Bose gas with SOC. The coupled dynamics of density and spin results in new features of spin dynamics. Analytic solution of spin helix in quasi-one-dimensional situation is obtained. In the adiabatic regime, persistent spin helix (PSH) protected by SU(2) symmetry is found. In the vicinity of PSH, the decay of transverse spin proceeds either parabolically or exponentially, depending on initial polarisation. By contrast, far away from adiabatic limit, transverse spin density and current oscillate in a way similar to the charge-current oscillation in LC circuit.  

Anyone interested is welcome to attend.