title: Quantum chaos triggered by precursors of a quantum phase transition: the dicke model.
abstract: We consider the Dicke Hamiltonian, a simple quantum-optical model which exhibits a zero-temperature quantum phase transition. We present numerical results demonstrating that at this transition the system changes from being quasi-integrable to quantum chaotic. By deriving an exact solution in the thermodynamic limit we relate this phenomenon to a localization-delocalization transition in which a macroscopic superposition is generated. We also describe the classical analogs of this behavior.
authors.affiliation: Department of Physics, UMIST, Manchester M60 1QD, United Kingdom.
authors.forename: Clive
authors.initials: C
authors.lastname: Emary
authors.forename: Tobias
authors.initials: T
authors.lastname: Brandes