Efficient basis for the Dicke Model I: theory and convergence in energy

Abstract: An extended bosonic coherent basis has been shown by Chen to provide numerically exact solutions of the finite-size Dicke model. The advantages in employing this basis, as compared with the photon number (Fock) basis, are exhibited to be valid for a large region of the Hamiltonian parameter space by analyzing the converged values of the ground state energy.