报告时间：7月11日 周三 下午2:30
报告题目： Quantum photon conversion with integrated nonlinear photonics
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 work on topological and nonreciprocal dynamics in a non-Hermitian optomechanical system [Nature 537, 80 (2016)]. Specifically, we realized topological energy transfer between nearly degenerate modes by adiabatically encircling an exceptional point (a singularity of the complex spectrum). We also demonstrated that this energy transfer is non-reciprocal: a given topological operation can only transfer energy in one direction. We have extended the topological and nonreciprocal dynamics to highly non-degenerate modes by exploiting a generic form of nonlinearity, which should allow these effects to be exploited in a very wide range of physical systems.
Haitan Xu is currently a postdoc at Harvard University. He received his Ph.D. degree from University of Maryland - College Park in 2014, and B.Sc. and M.Sc. degrees from Zhejiang University in 2007 and 2009. He was a postdoc at Yale University for three years from 2015 to 2018. He is both an experimentalist and a theorist, with research experience in multiple fields including optomechanics, topological physics, and quantum computation.