Theory of Bose-Einstein condensation and superfluidity of two-dimensional polaritons in an in-plane harmonic potential
Oleg L. Berman, Yu. E. Lozovik, David W. Snoke
Recent experiments have shown that it is possible to create an in-plane harmonic potential trap for a two-dimensional (2D) gas of exciton polaritons in a microcavity structure, and evidence has been reported of Bose-Einstein condensation of polaritons accumulated in this type of trap. We present here the theory of Bose-Einstein condensation (BEC) and superfluidity of the exciton polaritons in a harmonic potential trap. Along the way, we determine a general method for defining the superfluid fraction in a 2D trap, in terms of angular momentum representation. We show that in the continuum limit, as the trap becomes shallower, the superfluid fraction approaches the 2D Kosterlitz--Thouless limit, while the condensate fraction approaches zero, as expected.
arXiv:0803.3239•Physical Review B•Apr 16, 2008•57 citations