题 目：Novel many-body dynamics of Rydberg-dressed ultracold gases
报告人：李伟斌，副教授
主持人：白正阳，副研究员
时 间：2020年11月4日下午三点
地 点：光学大楼B325会议室（腾讯会议ID：977 758 806）
报告人简介：
李伟斌，诺丁汉大学物理与天文学院副教授。本科毕业于华中科技大学，博士毕业于中科院武汉物理与数学研究所。2007-2010年在德国马普复杂物理系统研究所博士后研究，2010-2012年欧盟玛丽-居丽学者，2013-2016年获得诺丁汉高级研究学者，2016-2020年诺丁汉大学物理与天文学院任助理教授，2020年成为副教授。
研究方向集中在超冷里德堡原子和分子气体和里德堡离子。在基于原子、离子系统的多体物理、量子光学、非线性物理、量子计算和模拟等方向做了一系列的理论研究，在Science、Nature、Nature子刊、PRX、PRL（13篇）等学术刊物发表多篇文章，相关理论预测得到了多个实验的验证。
报告内容简介：
We investigate quench dynamics of Bose-Einstein condensates of ultracold atomic gases with a soft-core-shaped long-range interaction. The soft-core interaction is induced by laser dressing ground-state atoms to a highly excited Rydberg state. In free space, the long-range interaction drastically alters the dispersion relation of the excitation, supporting both roton and maxon modes. Rotons are typically responsible for the creation of supersolids, while maxons are normally dynamically unstable in BECs with dipolar interactions. We show that maxon modes in the Rydberg-dressed condensate, on the contrary, are dynamically stable. We find that the maxon modes can be excited through an interaction quench, i.e., turning on the soft-core interaction instantaneously. The emergence of the maxon modes is accompanied by oscillations at high frequencies in the quantum depletion, while rotons lead to much slower oscillations. The dynamically stable excitation of the roton and maxon modes leads to persistent oscillations in the quantum depletion. When trapped in an optical lattice, dynamics of the atomic gas is governed by an extended Bose-Hubbard model. We propose a quench process by varying the atomic hopping linearly across phase boundaries of the Mott insulator-supersolid and supersolid-superfluid phases. The dynamical evolution of the superfluid order parameter exhibits a universal behavior at the early stage, largely independent of interactions. The dynamical evolution is significantly altered by strong, long-range interactions at later times. Particularly, we demonstrate that density wave excitation is important when the quench rate is small. Moreover, we show that the quench dynamics can be analyzed through time-of-flight images, i.e., measuring the momentum distribution and noise correlations. Finally I will introduce our ongoing work on Rydberg-dressed fermions.