Bloch Oscillations of an Exciton-polariton Bose-Einstein Condensate

We study theoretically Bloch oscillations of half-matter, half-light quasi-particles: exciton-polaritons. We propose an original structure for the observation of this phenomenon despite the constraints imposed by the relatively short lifetime of the particles and the limitations on the engineered periodic potential. First, we focus on the linear regime in a perfect lattice where regular oscillations are obtained. Second, we take into account a realistic structural disorder known to localize non-interacting particles, which is quite dramatic for propagation-related phenomena. In the non-linear condensed regime the renormalization of the energy provided by interactions between particles allows us to screen efficiently the disorder and to recover oscillations. This effect is useful only in a precise range of parameters outside of which the system becomes dynamically unstable. For a large chemical potential of the order of the potential's amplitude, a strong Landau-Zener tunneling tends to completely delocalize particles.