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Entanglement and Entropy in a Spin-Boson Quantum Phase Transition

N. Lambert·C. Emary·T. Brandes
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Abstract

We investigate the entanglement properties of an ensemble of atoms interacting with a single bosonic field mode via the Dicke (superradiance) Hamiltonian. The model exhibits a quantum phase transition and a well-understood thermodynamic limit, allowing the identification of both quantum and semi-classical many-body features in the behaviour of the entanglement. We consider the entanglement between the atoms and the field, an investigation initiated in [N. Lambert, C. Emary and T. Brandes, Phys. Rev. Lett. {\bf 92}, %073602 (2004)]. In the thermodynamic limit, we give exact results for all entanglement partitions and observe a logarithmic divergence of the atom-field entanglement, and discontinuities in the average linear entropy.

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N. Lambert, C. Emary, T. Brandes. 2004-12-08. Entanglement and Entropy in a Spin-Boson Quantum Phase Transition. https://doi.org/10.1103/physreva.71.053804

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