Eur. Phys. J. D (2015) 69: 241
https://doi.org/10.1140/epjd/e2015-60323-1

Regular Article

Large-N scaling behavior of the quantum fisher information in the Dicke model

Department of Physics, Chongqing University, Chongqing 400044, P.R. China

^a e-mail: yuyuzh@cqu.edu.cn

Received: 1 June 2015
Received in final form: 7 September 2015
Published online: 3 November 2015

Abstract

Quantum Fisher information (QFI) of the reduced two-atom state is employed to capture the quantum criticality of the superradiant phase transition in the Dicke model in the infinite size and finite-N systems respectively. The analytical expression of the QFI of its ground state is evaluated explicitly. And finite-size scaling analysis is performed with the large accessible system size due to the effective bosonic coherent-state technique. We also investigate the large-size scaling behavior of the scaled QFI of the reduced N-atom state and show the accurate exponent.