Exact diagonalisation of photon Bose–Einstein condensates with thermo-optic interaction

Abstract Although photon Bose–Einstein condensates have already been used for studying many interesting effects, the precise role of photon–photon interaction is not fully clarified up to now. In view this, it advantageous that these systems allow measuring both intensity light leaking out cavity and its spectrum at same time. Therefore, strength can be determined once via analysing condensate broadening examining interaction-induced modifications modes. As former method depends crucially on concrete shape trapping potential spatial resolution camera, interferometric methods promise more measurements. To this end, present paper works impact upon A quantum mechanical description interaction, including thermal cloud, builds theoretical backbone method. An exact diagonalisation approach introduced here exposes how effective modifies width gas. comparison with a variational based Gross–Pitaevskii equation quantifies contribution cloud in respective applications.