Enhancing quantum coherence in hybrid optomechanical systems with coherent feedback, atomic ensembles, and optical parametric amplifier

Abstract We theoretically investigate quantum coherence in a hybrid optomechanical system with a fixed mirror, mechanical oscillators, two-level atoms, and an optical parametric amplifier (OPA) within the cavity. A coherent feedback loop is created by redirecting part of the cavity's output field back into the cavity via an asymmetric beam splitter. Using numerical solutions of the Lyapunov equation and steady-state mean values, we quantify the Gaussian quantum coherence of the system. Our results show that the presence of OPA, coherent feedback, atomic ensembles, and strong laser power significantly enhance quantum coherence, while higher atomic decay rates, relative phase, and temperatures reduce it. This approach not only boosts quantum coherence but also improves resilience to temperature fluctuations, providing a robust foundation for quantum information processing.