Exploring chaos in Dicke Model using ground state fidelity and Loschmidt echo

TL;DR

This paper investigates quantum chaos in the Dicke Model by analyzing ground state fidelity and Loschmidt echo, revealing chaotic behavior in the super-radiant phase for finite atom numbers.

Contribution

It demonstrates the effectiveness of ground state fidelity and Loschmidt echo as indicators of chaos in the Dicke Model's super-radiant phase.

Findings

Ground state fidelity signals chaos in the super-radiant phase.

Loschmidt echo exhibits decay consistent with chaotic dynamics.

Chaotic signatures are evident even with finite atom numbers.

Abstract

We study the quantum critical behaviour of the Dicke Hamiltonian, with finite number of atoms and explore the signature of quantum chaos using measures like the ground state fidelity and the Loschmidt echo. We show that both these quantities clearly point to the chaotic nature of the system in the super-radiant phase.