Nonclassical correlated optical multistability at low photon level for cavity electromagnetically induced transparency

TL;DR

This paper investigates nonclassical optical multistability at very low photon levels in a cavity EIT system, revealing quantum fluctuation effects and tunable nonequilibrium phase transitions with potential quantum technology applications.

Contribution

It demonstrates the existence of nonclassical multistability at low photon numbers and shows the agreement between quantum and semiclassical models in this regime.

Findings

Bistability and multistability occur with photon-bunching statistics at low photon numbers.

Quantum fluctuations significantly influence nonequilibrium dynamics.

Semiclassical and quantum solutions agree when photon number is much less than one.

Abstract

We study the nonequilibrium dynamic behaviors in a driven-dissipative single-atom cavity electromagnetically induced transparency. The optical bistability and multistability beyond a Kerr nonlinearity are observed utilizing the optical Stark shift induced strong nonlinearity. We show that the nonequilibrium dynamical phase transition between bistability and multistability is highly tunable by the system parameters in a large parameter region. The first-order dissipative optical bistability (multistability) always corresponds to the photon-bunching quantum statistics, which indicates that the quantum fluctuations and correlations play important roles in nonequilibrium dynamics.Interestingly, bistability and multistability with photon-bunching quantum statistics occurring at extremely low steady-state cavity photon number are observed, even under a very strong cavity driven field. Furthermore, we demonstrate that the unique cavity steady-state solution of the full quantum calculation is excellently consistent with the lowest solution based on the semiclassical mean-field approach in bistability and multistability regimes when the cavity photon number is much less than unity, albeit these nonclassical quantum states should possess strong quantum fluctuations in this parameter regime. Our results pave the way to exploring nonclassical correlated optical multistability in quantum regime, which may bring exciting opportunities for potential applications from quantum information processing to quantum metrology.