Nonclassical Photon-Bundle Correlations in Quantum Rabi Models

TL;DR

This paper explores controllable nonclassical photon-bundle correlations in the quantum Rabi model, revealing tunable quantum transitions and potential for high-purity multi-photon sources at finite temperature.

Contribution

It introduces anisotropic coupling and Stark interactions to enrich photon statistical behaviors and links extreme correlations to excited-state quantum phase transitions.

Findings

Controllable nonclassical transitions between photon bunching and antibunching.

Enhanced photon statistical behaviors via anisotropic coupling and Stark interactions.

Correlations linked to excited-state quantum phase transitions.

Abstract

We investigate nonclassical photon-bundle correlations in the quantum Rabi model and its extended cases, using the quantum dressed master equation. By tuning the light--matter coupling strength at finite temperature, the quantum Rabi model exhibits controllable nonclassical transitions between two-photon bundle bunching and antibunching, allowing for the two-photon bundle emission and statistics. We further introduce anisotropic coupling and nonlinear Stark interactions, which enrich the photon statistical behaviors and provide additional tunability of photon-bundle correlations. Extreme correlation behaviors are found to be closely linked to excited-state quantum phase transitions, suggesting a potential pathway for predicting and exploiting excited-state phenomena. These effects can be controlled solely by tuning intrinsic system parameters, without the need for an external modulating field. The quantum Rabi model family thus provides a flexible and experimentally feasible platform for high-purity photon bundle generation and controllable multi-photon sources.