Universal dynamics of superradiant phase transition in the anisotropic quantum Rabi model

TL;DR

This paper explores the universal non-equilibrium dynamics and critical behavior of the superradiant phase transition in the anisotropic quantum Rabi model, combining analytical and numerical methods to reveal anisotropy-independent critical exponents.

Contribution

It provides a comprehensive analysis of the critical exponents and dynamic behavior of the superradiant phase transition in the anisotropic quantum Rabi model, highlighting their universality.

Findings

Critical exponents are independent of anisotropy ratio.

Analytical and numerical results are consistent.

Dynamic methods effectively reveal universal critical behavior.

Abstract

We investigate the universally non-equilibrium dynamics of superradiant phase transition in the anisotropic quantum Rabi model. By introducing position and momentum operators, we obtain the ground states and their excitation gaps for both normal and superradiant phases via perturbation theory. We analytically extract the critical exponents from the excitation gap and the diverging length scale near the critical point, and find that the critical exponents are independent upon the anisotropy ratio. Moreover, by simulating the real-time dynamics across the critical point, we numerically extract the critical exponents from the phase transition delay and the diverging length scale, which are well consistent with the analytical ones. Our study provides a dynamic way to explore universal critical behaviors in the quantum Rabi model.