A spinor atom-SQUID
Over the past few years, there has been a concerted effort at NIST
studying the atomic analogue of a Superconducting Quantum Interference
Device (SQUID). The atom-SQUID consists of a Bose-Einstein condensate
in a ring trap with a rotating external weak link. The system displays
the phenomena of persistent current and hysteresis. In this talk, I will
present our results on the the effect of the spin degree of freedom on
the stability of persistent-current states and hysteresis in a spin-1
atom-SQUID. Inter-atomic interactions induces coherent oscillations
between the spin levels while conserving total magnetisation.
We study the stability by calculating the Bogoliubov spectrum
of the mean-field solutions of a two-mode approximation and the
solutions of Gross-Pitaevskii equation.