标题： 通过无测量的相干反馈冷却光学悬浮纳米粒子 显示英文标题

标题： Cooling of an optically levitated nanoparticle via measurement-free coherent feedback

摘要： 我们展示了对悬浮纳米粒子的相干、无测量的光学反馈控制，实现了少量声子的激发态。 与基于测量的反馈不同，这种全光学方案保留了机械运动和反馈信号之间的关联性。 调整反馈相位和延迟可以对系统动力学进行精确且可调的控制。 目前的冷却性能受到相位噪声的限制，我们在一个理论框架内分析了这一问题，该框架概述了达到运动基态的约束和前景。 我们的结果确立了相干反馈作为操控悬浮系统量子控制的强大工具，其应用超出了质心冷却的范围。 显示英文摘要

摘要： We demonstrate coherent, measurement-free optical feedback control of a levitated nanoparticle, achieving phonon occupations down to a few hundred phonons. Unlike measurement-based feedback, this all-optical scheme preserves the correlations between mechanical motion and the feedback signal. Adjustment of the feedback phase and delay provides precise and tunable control over the system dynamics. The ultimate cooling performance is currently limited by phase noise, which we analyze within a theoretical framework that outlines the constraints and prospects for reaching the motional ground state. Our results establish coherent feedback as a powerful tool for quantum control of levitated systems, extending beyond center-of-mass cooling.