题 目：聆听自旋的噪音-Listening carefully to the noise of spins
报告人：李福祥
时 间：5月17日（周三 ），上午10:00-10:40
地 点：同济大学物理馆512会议室
报告摘要：
Noise is not always that annoying. Articulated by the well-known Fluctuation-Dissipation theorem in equilibrium thermodynamics, fluctuation itself (i.e., noise) can reveal all the dynamic information of the system. Optical spin-noise spectroscopy (SNS) is such a minimally invasive route towards obtaining dynamical information about semiconductors and atomic gases by measuring time-dependent spin fluctuations. Most of the experimental and theoretical studies have been focused so far on the second-order spin correlator. Here I will discuss our efforts of pushing forward this powerful technique towards obtaining more information. I will talk about our theoretical study on the non-equilibrium spin noise spectroscopy and recent study on higher-order correlators, i.e. 3rd and 4th order, which are expected to reveal more information than second order correlator. We developed a stochastic path integral formation and found a universal relation among all the higher-order parameters. Applying this method to atomic gas with noisy magnetic field, we predicted and observed the pattern of 4th order correlator. 3rd order correlator is also predicted and measured in single quantum dot, which reveals inhomogeneous and homogeneous broadening effects and moreover, quantum measurement effects.
个人简介：
报告人现在是美国Los Alamos国家实验室的director's postdoctoral fellow. 先前曾就读于南京大学和美国得州农工大学，获得学士，硕士和博士学位。他的主要研究方向包括磁学，自旋电子学，以及量子控制方面，并且与德国和美国的很多实验组展开了长期密切的合作。以第一作者或同等贡献身份发表Phys. Rev. Lett. 4篇，总共在Nature Physics, Phys. Rev. A, Phys. Rev. B等国际著名期刊上发表20余篇学术论文。