报告人：王大军 教授丨香港中文大学

邀请人：李朝红 教授

时  间：2025年4月30日（周三）11:00-12:00

地  点：深圳大学粤海校区光电所315会议室

报告摘要：

The two-species  Bose-Einstein condensate (BEC) of ultracold dilute atomic gases has been  a quantum system of long-standing interest. In recent years, many  previously unexplored phenomena in this system have been observed by  manipulating the interplay between inter- and intra-species  interactions. In this talk, I will present two experiments conducted  with the double BEC of sodium and rubidium atoms. Using a Feshbach  resonance, we tuned the inter-species interaction to be sufficiently  attractive for the system to collapse in the mean-field regime. However,  instead of collapsing, we observed the formation of a stable liquid  droplet of the two species, stabilized by the beyond-mean-field  Lee-Huang-Yang correction. On the other hand, in the regime of large  repulsive inter-species interaction, we found that the Na BEC forms a  closed shell surrounding the Rb BEC. We studied the self-interference  phenomenon of the shell BEC during its free expansion. Additionally,  several other experiments, including probing the hollowing transition of  the Na BEC using collective excitations, will also be discussed.

报告人简介:

Prof. WANG Dajun  obtained his PhD from the University of Connecticut in 2007. Before  joining the Chinese University of Hong Kong, he worked as a postdoctoral  research associate at JILA/University of Colorado from 2007 to 2010.  His main research interests include ultracold polar molecules, ultracold  chemical reaction, dipolar many-body physics, ultracold mixtures, and  spinor systems.