Tomka, Michael Baeriswyl, Dionys Gritsev, Vladimir 2013-11-01 We study the dynamics of a driven Dicke model, where the collective spin is rotated with a constant velocity around a fixed axis. The time evolution of the mean photon number and of the atomic inversion is calculated using, on the one hand, a numerical technique for the quantum dynamics of a small number of two-level atoms and, on the other hand, time-dependent mean-field theory for the limit of a large number of atoms. We observe a reduction in the mean photon number compared to its equilibrium value. This dynamically generated darkness is particularly pronounced slightly above the transition to a superradiant phase. We attribute the effect to a slowing-down of the motion in the classical limit of a large ensemble and to an interplay of dynamic and geometric phases in the quantum case. application/pdf https://folia.unifr.ch/global/documents/303615 https://folia.unifr.ch/documents/303615/files/gri_dgr.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevA.88.053801 info:eu-repo/semantics/openAccess License undefined Physical Review A. - 2014, vol. 88, no. 5, p. 053801 info:eu-repo/classification/udc/53 Dynamically generated reduction of the mean photon number in the Dicke model http://purl.org/coar/resource_type/c_6501