Nonreciprocal enhancement of macroscopic entanglement with noise tolerance

The entanglement of different macroscopic objects can provide crucial resources for various quantum applications and quantum-enabled devices. The generation, manipulation, and enhancement of entanglement are pivotal areas of research. In this study, we introduce an approach for producing enhanced nonreciprocal entanglement in a hybrid spinning optomechanical system. By exploiting the Sagnac effect to break the time-reversal symmetry of the system, we successfully generate and amplify the nonreciprocal bipartite entanglement between the atomic ensemble and mechanical oscillator, exhibiting an approximately twofold enhancement under competitive equilibrium conditions. Furthermore, we investigate and quantify the nonreciprocal tripartite entanglement encompassing the atomic ensemble, optical cavity, and mechanical oscillator by employing the residual contangle measurement. We find that the nonreciprocal bipartite (tripartite) entanglement is not only enlarged almost two (five) times, but also noise resistant. The proposed scheme of enhanced bipartite and tripartite entanglement has the potential to advance a wide range of quantum technologies, spanning from quantum information processing to quantum sensing applications.