Dissipation and detection of polaritons in ultrastrong coupling regime

TL;DR

This paper theoretically investigates dissipative polariton systems in the ultrastrong coupling regime, revealing non-vacuum reservoir states and confirming decay to the ground state without photon detection.

Contribution

It introduces a non-vacuum reservoir model in the master equation and input-output formalism for ultrastrong coupling polaritons, without using the rotating-wave approximation.

Findings

Reservoirs are squeezed and correlated in the ground state.

Polariton system decays to its ground state.

No photon detection occurs in the ground state.

Abstract

We have investigated theoretically a dissipative polariton system in the ultrastrong light-matter coupling regime without using the rotating-wave approximation on system-reservoir coupling. Photons in a cavity and excitations in matter respectively couple two large ensembles of harmonic oscillators (photonic and excitonic reservoirs). Inheriting the quantum statistics of polaritons in the ultrastrong coupling regime, in the ground state of the whole system, the two reservoirs are not in the vacuum states but they are squeezed and correlated. We suppose this non-vacuum reservoir state in the master equation and in the input-output formalism with Langevin equations. Both two approaches consistently guarantee the decay of polariton system to its ground state, and no photon detection is also obtained when the polariton system is in the ground state.