Limitations of squeezing due to collisional decoherence in BoseEinstein condensates
Abstract
We study the limitations for entanglement due to collisional decoherence in a BoseEinstein condensate. Specifically we consider relative number squeezing between photons and atoms coupled out from a homogeneous condensate. We study the decay of excited quasiparticle modes due to collisions in condensates of atoms with one or two internal degrees of freedom. The time evolution of these modes is determined in the linear response approximation to the deviation from equilibrium. We use HeisenbergLangevin equations to derive equations of motion for the densities and higher correlation functions which determine the squeezing. In this way we can show that decoherence due to quasiparticle interactions imposes an important limit on the degree of number squeezing which may be achieved. Our results are also relevant for the determination of decoherence times in other experiments based on entanglement, e.g. the slowing and stopping of light in condensed atomic gases using dark states.
 Publication:

Journal of Physics B Atomic Molecular Physics
 Pub Date:
 May 2002
 DOI:
 10.1088/09534075/35/10/312
 arXiv:
 arXiv:quantph/0202012
 Bibcode:
 2002JPhB...35.2337G
 Keywords:

 Quantum Physics
 EPrint:
 16 pages RevTeX, 3 figures