# $\mathcal{PT}$-symmetry from Lindblad dynamics in an optomechanical system

## TL;DR

This paper demonstrates how optomechanical systems can exhibit $ ext{PT}$-symmetry breaking transitions through Lindblad dynamics, connecting non-Hermitian quantum models with experimentally realizable optomechanical setups.

## Contribution

It establishes a link between $ ext{PT}$-symmetry breaking and optomechanical state transfer dynamics, providing a pathway to realize non-Hermitian Hamiltonians at the quantum level.

## Key findings

- Transition from mode-hybridization to damped dynamics signals $ ext{PT}$-symmetry breaking.
- Comparison of Lindblad and $ ext{PT}$-symmetric Hamiltonian dynamics identifies conditions for equivalence.
- Numerical simulations show quantum state evolution at zero and room temperature.

## Abstract

The optomechanical state transfer protocol provides effective, lossy, quantum beam-splitter-like dynamics where the strength of the coupling between the electromagnetic and mechanical modes is controlled by the optical steady-state amplitude. By restricting to a subspace with no losses, we argue that the transition from mode-hybridization in the strong coupling regime to the damped-dynamics in the weak coupling regime, is a signature of the passive parity-time ($\mathcal{PT}$) symmetry breaking transition in the underlying non-Hermitian quantum dimer. We compare the dynamics generated by the quantum open system (Langevin or Lindblad) approach to that of the $\mathcal{PT}$-symmetric Hamiltonian, to characterize the cases where the two are identical. Additionally, we numerically explore the evolution of separable and correlated number states at zero temperature as well as thermal initial state evolution at room temperature. Our results provide a pathway for realizing non-Hermitian Hamiltonians in optomechanical systems at a quantum level.