Spontaneous symmetry breaking in nonlinear superradiance

Creation and manipulation of non-classical states of light is rapidly becoming the focus of modern attosecond science. Here, we demonstrate numerically how such states can arise by considering a modification of the well-known problem of superradiance encountered already by Dicke. Similarly to him, we investigate photon emission by ensembles of indistinguishable atoms. In contrast to him, however, we leverage symmetry-based selection rules to suppress emission of single photons by single atoms. A steady state is therefore only reached following a spontaneous transition into a collective symmetry-broken state of atoms and photonic modes. The novel non-Markovian, non-perturbative method applied allows us to observe a large quantum state of light form and exhibit drastically non-classical statistics once the system undergoes a symmetry-breaking transition.