近日，美国麻省理工学院Vladan Vuletic团队研究了光学时钟跃迁的量子放大全局相位光谱。相关论文于2025年10月8日发表在《自然》杂志上。

光学点阵钟处于精密计量学的前沿，运行在由量子噪声设定的标准量子极限附近。利用量子纠缠为超越这一极限提供了一条有前景的途径；然而，在可扩展性和测量分辨率要求方面存在实际困难。

研究组采用完整量子门概念来开发一种新的rabi型“全局相位光谱”，其应用失谐敏感的全局Aharonov-Anandan相位。通过这种方法，研究组可以在光时钟跃迁上演示量子放大的时间反转光谱，该光谱实现了直接测量的2.4（7）dB计量增益和4.0（8）dB的激光噪声灵敏度提高，超过了标准量子极限。

为此，研究组引入旋转回波来保护光原子耦合中的动力学不均匀性，并通过两个核自旋态的对称相位编码实现激光噪声消除的差分测量。该技术不受测量分辨率的限制，尺度很容易成为纠缠相互作用的全局性质应用，并且对典型的实验缺陷表现出很高的弹性。研究组期望它能广泛应用于下一代原子钟和其他接近基本量子精度极限的量子传感器。

附：英文原文

Title: Quantum-amplified global-phase spectroscopy on an optical clock transition

Author: Zaporski, Leon, Liu, Qi, Velez, Gustavo, Radzihovsky, Matthew, Li, Zeyang, Colombo, Simone, Pedrozo-Peafiel, Edwin, Vuleti, Vladan

Issue&Volume: 2025-10-08

Abstract: Optical lattice clocks are at the forefront of precision metrology1,2,3,4,5,6, operating near a standard quantum limit set by quantum noise4,7. Harnessing quantum entanglement offers a promising route to surpass this limit8,9,10,11,12,13,14,15; however, there are practical difficulties in terms of scalability and measurement resolution requirements16,17. Here we adapt the holonomic quantum gate concept18 to develop a new Rabi-type ‘global-phase spectroscopy’ that uses the detuning-sensitive global Aharonov–Anandan phase19. With this approach, we can demonstrate quantum-amplified time-reversal spectroscopy on an optical clock transition that achieves directly measured 2.4(7)dB metrological gain and 4.0(8)dB improvement in laser noise sensitivity beyond the standard quantum limit. To this end, we introduce rotary echo to protect the dynamics from inhomogeneities in light–atom coupling and implement a laser-noise-cancelling differential measurement through symmetric phase encoding in two nuclear spin states. Our technique is not limited by measurement resolution, scales easily because of the global nature of entangling interaction and exhibits high resilience to typical experimental imperfections. We expect it to be broadly applicable to next-generation atomic clocks and other quantum sensors approaching the fundamental quantum precision limits20,21,22.

DOI: 10.1038/s41586-025-09578-8

Source: https://www.nature.com/articles/s41586-025-09578-8