%0 Journal Article
%T Solution of the Dicke model for N=3
%A Daniel Braak
%J Physics
%D 2013
%I arXiv
%R 10.1088/0953-4075/46/22/224007
%X The N=3 Dicke model couples three qubits to a single radiation mode via dipole interaction and constitutes the simplest quantum-optical system allowing for Greenberger-Horne-Zeilinger states. In contrast to the case N=1 (the Rabi model), it is non-integrable if the counter-rotating terms are included. The spectrum is determined analytically, employing the singularity structure of an associated differential equation. While quasi-exact eigenstates known from the Rabi model do not exist, a novel type of spectral degeneracy becomes possible which is not associated with a symmetry of the system.
%U http://arxiv.org/abs/1304.2529v1