报告题目：Topological and nonreciprocal dynamics in optomechanics

报告摘要：Non-Hermitian systems exhibit rich physical phenomena that open the door to qualitatively new forms of control. Here I will introduce our recent works on topological and nonreciprocal dynamics in non-Hermitian optomechanical systems [Nature 537, 80 (2016); Nature 568, 65 (2019)]. Specifically, we realized topological energy transfer by adiabatically encircling an exceptional point (a singularity of the complex spectrum). We also demonstrated that this energy transfer is non-reciprocal: a certain topological operation can only transfer energy in one direction. Furthermore, we realized stable nonreciprocal coupling between phonon modes with optomechanical interference. We achieved phonon isolation which can be tuned continuously over a wide range from -30dB to 30dB. We showed the nonreciprocal phonon transfer as a new way to control the thermal fluctuation of phonon modes by controlling laser phases.

报告人简介：徐海潭，北京大学304am永利集团官方 研究员，主要研究光力学中的拓扑物理、量子调控、量子计算和精密测量等前沿物理问题和应用，多项成果发表于Nature、Nature Physics、Nature Communications、PRL等学术期刊上。徐海潭本科和硕士毕业于浙江大学，博士毕业于美国马里兰大学，并先后在耶鲁大学和哈佛大学做博士后研究工作，现在是北京大学304am永利集团官方博士生导师。

报告时间：2020年6月17日下午 03:50