We address the macroscopic quantumness of the state of mechanical systems subjected to conditional protocols devised for state engineering in cavity optomechanics. We use a measure of macroscopicity based on phase-space methods. We cover the domain from weak to strong optomechanical coupling, illustrating how measurements performed over the cavity field that drives the dynamics of a mechanical system are able to steer the latter towards large quantum coherent states. The effect of losses is evaluated for the case of an open cavity, and analyzed in terms of the features of the Wigner functions of the state of the mechanical system. We also address the case of engineered phonon-subtracted mechanical systems, in full open-system configuration, demonstrating the existence of optimal working points for the sake of mesoscopic quantumness. Our study is relevant for and applicable to a broad range of settings, from clamped to levitated mechanical systems.

中文翻译：

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光学调节机械系统的宏观量子性

我们解决了机械系统状态的宏观量子性，该状态受到为腔光力学中的状态工程设计的条件协议。我们使用基于相空间方法的宏观度量。我们涵盖了从弱光机耦合到强光机耦合的领域，说明了在驱动机械系统动力学的腔场上执行的测量如何能够将后者引导到大的量子相干态。在开腔的情况下评估了损耗的影响，并根据机械系统状态的 Wigner 函数的特征进行了分析。我们还解决了在完全开放系统配置中设计的声子减去机械系统的情况，证明了为了介观量子性而存在最佳工作点。