报告题目：Stable Atomic Magnetometer in Parity-Time Symmetry Broken Phase

报告人：赵楠研究员

报告摘要:In this talk, I will discuss our recent research progress on magnetic resonance of atomic magnetometer. Random motion of spins is usually detrimental in magnetic resonance experiments. The spin diffusion in nonuniform magnetic fields causes broadening of the resonance and limits the sensitivity and the spectral resolution in applications like magnetic resonance spectroscopy. Recently, by observation of the parity-time (PT) phase transition of diffusive spins in gradient magnetic fields, we show that the spatial degrees of freedom of atoms could become a resource, rather than harmful, for high-precision measurement of weak signals. In the normal phase with zero or low gradient fields, the diffusion results in dissipation of spin precession. However, by increasing the field gradient, the spin system undergoes a PT transition, and enters the PT symmetry broken phase. In this novel phase, the spin precession frequency splits due to spatial localization of the eigenmodes. We demonstrate that, using these spatial-motion-induced split frequencies, the spin system can serve as a stable magnetometer, whose output is insensitive to the inevitable long-term drift of control parameters. This opens a door to detect extremely weak signals in imperfectly controlled environments.

报告人简介：赵楠，北京计算科学研究中心研究员。2003年获清华大学物理学学士学位，2009年获清华大学物理学博士学位。先后在中国香港中文大学物理系（访问学者、博士后）和德国斯图加特大学（博士后）工作，2012年入选国家人才计划。近期研究兴趣集中在基于气态热原子自旋的量子精密测量，特别是核磁共振陀螺的物理原理及其应用。

报告时间：4月6日下午三点

报告地点：四教东149

学院联系人：孔嘉