Quantum phase transition in the Dicke model with critical and noncritical entanglement
Quantum phase transition in the Dicke model with critical and noncritical entanglement
We study the quantum phase transition of the Dicke model in the classical oscillator limit, where it occurs already for finite spin length. In contrast to the classical spin limit, for which spin-oscillator entanglement diverges at the transition, entanglement in the classical oscillator limit remains small. We derive the quantum …