Speaker
Prof.
David Campbell
(Boston University, USA)
Description
Abstract: Recently [1] we have shown that a "global phase
space" (GPS) approach provides valuable understanding of
the long-time coherence and Einstein-Podolsky-Rosen
entanglement of a Bose-Einstein Condensate (BEC) trapped
in a double-well optical lattice ("BEC dimer"). In particular,
the GPS approach allows one to distinguish purely quantum
effects from those which are captured by semi-classical
methods. The GPS approach in Ref. (1) was applied in the
limit of zero dissipation. After reviewing the key results in
this limit, we extend the approach to allow for dissipation
and again compare the results with relevant experiments.
Surprisingly, although consistent with some prior
exploratory studies, we find that dissipation can actually
enhance coherence in certain instances, particularly around
self-trapped modes, corresponding to fixed points in the
classical phase space. We explain a number of interesting
features of this enhancement and argue that, in spatially
extended systems (corresponding to multi-well optical
lattices), these localized, self-trapped modes may also play a
role in enhancing coherence.
[1] Holger Hennig, Dirk Witthaut, and David K. Campbell,
Phys. Rev. A 86, 051640 [R] 2012.
