Accurate numerical solution to the finite-size Dicke model

TL;DR

This paper introduces a novel numerical method using extended bosonic coherent states to solve the finite-size Dicke model with unprecedented system sizes, enabling detailed analysis of finite-size effects and resolving previous discrepancies in scaling exponents.

Contribution

A new numerical technique employing extended bosonic coherent states for exact solutions of the finite-size Dicke model, significantly expanding accessible system sizes.

Findings

System size increased by two orders of magnitude compared to previous methods.

Finite-size scaling of ground-state energy, Berry phase, and concurrence analyzed.

Discrepancy in the scaling exponent of concurrence resolved.

Abstract

By using extended bosonic coherent states, a new technique to solve the Dicke model exactly is proposed in the numerical sense. The accessible system size is two orders of magnitude higher than that reported in literature. Finite-size scaling for several observables, such as the ground-state energy, Berry phase, and concurrence are analyzed. The existing discrepancy for the scaling exponent of the concurrence is reconciled.