Deplano Q, Pontin A, Ranfagni A, Marino F, Marin F
Dipartimento di Fisica e Astronomia, Università di Firenze, Sesto Fiorentino (FI), Italy.
INFN, Sezione di Firenze, Sesto Fiorentino (FI), Italy.
Nat Commun. 2025 May 6;16(1):4215. doi: 10.1038/s41467-025-59213-3.
In recent years, levitated optomechanics has delivered on the promise of reaching the motional quantum ground state. An important next milestone of the field would be the generation of mechanical entanglement. An ideal candidate is the two-dimensional motion in the polarization plane of an optical tweezer inside an optical cavity, where optical and mechanical modes are coupled via coherent scattering. Achieving this goal requires two key conditions: two-dimensional ground state cooling along with substantial spectral overlap between the two modes. The latter is essential to generate the necessary correlations, but unfortunately, it hinders efficient cooling thus narrowing the useful parameter space. In this work, we report the achievement of a high purity two-dimensional state in a regime where the strong optomechanical coupling induces the desired spectral overlap between oscillations in different directions, as reflected in the non-trivial spectral shape of the detected cavity field. As a result, significant correlations consistently arise between any pair of orthogonal directions, preventing the motion from being reduced to two independent one-dimensional oscillators and leading to higher purity compared to that scenario. Our system serves as an excellent platform for realizing continuous variable entanglement in two-dimensional motion.
近年来，悬浮光力学已经实现了达到运动量子基态的目标。该领域的下一个重要里程碑将是产生机械纠缠。一个理想的候选方案是光腔内光镊偏振平面内的二维运动，其中光学模式和机械模式通过相干散射耦合。实现这一目标需要两个关键条件：二维基态冷却以及两种模式之间有大量的光谱重叠。后者对于产生必要的相关性至关重要，但不幸的是，它阻碍了高效冷却，从而缩小了有用的参数空间。在这项工作中，我们报告了在一种情况下实现了高纯度二维状态，其中强光机械耦合在不同方向的振荡之间诱导出所需的光谱重叠，这反映在检测到的腔场的非平凡光谱形状中。结果，在任意一对正交方向之间始终出现显著的相关性，防止运动简化为两个独立的一维振荡器，并且与那种情况相比导致更高的纯度。我们的系统是在二维运动中实现连续变量纠缠的优秀平台。
