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BEC-BCS crossover in a system of microcavity polaritons

Jonathan Keeling** MIT**
__Abstract:__

Recently, microcavity polaritons have been studied as a possible

candidate for observation of Bose Condensation of quasiparticles in

solid state systems.

Such systems consist of planar microcavities containing quantum

wells, in which the quantum-well excitons are strongly coupled to the

confined photon modes, leading to new quasi-particles: microcavity

polaritons. Because of the photonic component, these particles

have a low effective mass, which suggests that condensation may be

possible at elevated temperatures.

After introducing these systems, and providing a brief review of the

results of experiments looking for condensation, I will explain how

including internal structure of polaritons modifies the phase

boundary. While at low densities the transition temperature is

controlled by the effective mass; at higher, yet experimentally

accessible densities, the phase transition becomes more

mean-field-like, and the critical temperature is instead given by a

BCS-like form.

Keeling et al. Phys. Rev. Lett. 93 226403 (2004)

Keeling et al. Phys. Rev. B. 72 115320 (2005)