报告题目： 利用原子旋量凝聚体的向列压缩实现无噪声量子放大

报告人：尤力（清华大学）

报告时间、地点：2023/5/18 15:30-16:30 西区科技实验楼东楼307

报告摘要：Quantum entanglement can provide enhanced precision beyond standard quantum limit (SQL), the highest precision achievable with classical means. It remains challenging, however, to observe large enhancement limited by the abilities to prepare, maintain, manipulate, and detect entanglement. In this talk, I will report nonlinear interferometry protocol with echoed spin-nematic squeezing in a spinor atomic Bose-Einstein condensate. Spin-nematic squeezed states are generated by spin-mixing, an atomic analogue to optical four-wave-mixing. Employed as probe states for phase sensing, the squeezed states are refocused back to the immediate vicinity of the (classical) initial state by state-flip caused echo of the same spin-mixing dynamics, leading to encoded phases preferentially amplified over noise. A sensitivity of 15.6 ± 0.5 decibels (dB) for small-angle Rabi rotation beyond the SQL of 26400 atoms as well as 16.6 ± 1.1 dB for phase sensing in Ramsey-like interferometry are observed. The absolute phase sensitivity for the latter extrapolates to 222.5 pT/√34 Hz for sensing near-resonant microwave field at a probe volume of 18 μm3. Our work highlights the exceptional many-body coherence of spin-nematic squeezed states and points to their possible quantum metrological applications in atomic magnetometer, atomic optical clock, and fundamental tests of Lorentz symmetry violation etc.

报告人简介：尤力，原子物理与精密测量学家。从事原子物理、量子光学、量子信息和量子计算领域的研究工作。1987年毕业于南京大学获得学士学位，1993年科罗拉多大学获得博士学位。1996-2009年任教于佐治亚理工学院。2009年至今任清华大学物理系教授。

主要学术奖励：

Fellow, American Physical Society, 2007

美国自然科学基金Career Award (Faculty Early Career Development), 1997-2002

美国海军研究室 ONR Young Investigator Award (YIP Program), 1997-2000