Spontaneous Conversion from Virtual to Real Photons in the Ultrastrong Coupling Regime

TL;DR

This paper demonstrates that in the ultrastrong light-matter coupling regime, virtual photon pairs can spontaneously convert into real photons without external stimuli, revealing a new quantum optical phenomenon.

Contribution

It introduces a novel spontaneous virtual-to-real photon conversion mechanism occurring in the ultrastrong coupling regime without external driving.

Findings

Virtual photon pairs spontaneously convert to real photons in the ultrastrong coupling regime.

The phenomenon occurs without external forces or time-dependent Hamiltonian parameters.

It applies to semiconductor and superconducting quantum optical systems.

Abstract

We show that a spontaneous release of virtual photon pairs can occur in a quantum optical system in the ultrastrong coupling regime. In this regime, which is attracting interest both in semiconductor and superconducting systems, the light-matter coupling rate {\Omega}R becomes comparable to the bare resonance frequency of photons {\omega}0. In contrast to the dynamical Casimir effect and other pair creation mechanisms, this phenomenon does not require external forces or time dependent parameters in the Hamiltonian.