Implication of giant photon bunching on quantum phase transition in the dissipative anisotropic quantum Rabi model

TL;DR

This paper explores how giant photon bunching signals can indicate first-order quantum phase transitions in the dissipative anisotropic quantum Rabi model, revealing new insights into photon statistics at strong coupling.

Contribution

It demonstrates the analytical and numerical connection between photon bunching and quantum phase transitions in a dissipative anisotropic quantum Rabi model, highlighting the role of photon statistics as a diagnostic tool.

Findings

Giant photon-bunching correlates with first-order quantum phase transition.

Photon-bunching peaks are prominent at deep-strong coupling regimes.

Photon-bunching measurement can characterize quantum phase transitions.

Abstract

We investigate the quantum phase transition in the dissipative anisotropic quantum Rabi model in the framework of quantum dressed master equation. From perspectives of both numerical and analytical analysis, we unravel the implication of the giant photon-bunching feature on the first-order quantum phase transition. The observed two-photon statistics can be well described analytically within a few lowest eigenstates at the low temperature. Moreover, such significant photon-bunching peak is generally exhibited at the deep-strong qubit-photon coupling, which is however lacking in the dissipative isotropic quantum Rabi model. Therefore, we suggest that the photon-bunching measurement is helpful to characterize the first-order QPT of the qubit-photon hybrid systems.