Quantum theory of an exciton condensate subject to radiative decay
P. Stenius
Semiconductor excitons obey Bose-Einstein statistics in the low-density limit. In this paper, a two-level quantum model for an exciton condensate subject to radiative decay is presented. The condensate state has a well-defined exciton number and a slow phase diffusion rate analogous to a coherent state created by a (photon) laser. Since excitons recombine radiatively, the statistics of the device can be observed by photodetection. Our analytical and numerical results at steady state reveal that the change in population statistics of the ground state is gradual across the threshold region, above which a condensate forms. When radiative losses are present, the condensate mode is ``quasicoherent;'' in the limit of no losses a coherent state is approached. Far below threshold the ground state is well described by a thermal distribution. The higher level, that is the ``pump,'' remains thermally distributed at all times.
Physical review. B, Condensed matter•Nov 15, 1999•4 citations