报告题目：tracold Quantum Gases–A FascinatingPlayground for Basic Research in Physics

报告人： Axel Pelster

报告时间：2017年10月16日（周一）上午10:30

报告地点：理学院第二实验楼二楼会议室

报告内容：

The talkprovides an introduction into ultracold dilute atomic gases and discussesseveral illustrative examples where this emerging fields allows importantinsights into basic research in physics. We start with reviewing the propertiesof Bose-Einstein condensates (BECs) with the anisotropic and long-rangedipole-dipole interaction. To this end we investigate the influence of quantumfluctuations upon the equilibrium configuration and the time-of-flightdynamics. We find that both atomic magnetic and molecular electric dipolar BECsoffer promising scenarios for detecting beyond mean-field effects. Furthermore,we report on recent progress in understanding the properties of ultracoldbosonic atoms in potentials with quenched disorder. This notoriously difficultdirty boson problem is experimentally relevant for the miniaturization of BECson chips and can also be studied by tailoring disorder potentials via laserspeckle fields. Theoretically it is intriguing because of the competition oflocalization and interaction as well as of disorder and superfluidity. Finally,systems of ultracold bosonic gases in optical lattices have recently become apopular research topic as they represent model systems for quantum phasetransitions in solid-state physics with a yet unprecendented level of control.For a small laser strength the bosons can tunnel from site to site and explorethe whole lattice, which leads to a superfluid phase. In the opposite situationof a large laser strength the bosons can no longer tunnel to the neighboringsites, so the occupation number of the sites is fixed, thus a so-called Mottphase emerges. We discuss a Ginzburg-Landau theory for the underlyingBose-Hubbard model which allows to determine the location of the quantum phasetransition from the superfluid to the Mott phase.

报告人简介：

Priv.-Doz. Dr. Axel Pelster, AdjunctProfessor of ICRANET Faculty and now works at Technische UniversitätKaiserslautern in Germany. He has published more than 100 SCI papers on the topmagazines including Physical Review Letter and Nature Communication. Hisresearch area includes Quantum Statistics, Bose-Einstein Condensation andRenormalization Group Theory of Critical Phenomena.

代表性论文

1.X.-F. Zhang, S. Hu, A. Pelster, and S.Eggert: Quantum Domain Walls Induce Incommensurate Supersolid Phase onthe Anisotropic Triangular Lattice; Physical Review Letters 117, 193210/1-6(2016) arXiv:1605. 1237.

2.B. Santra, C. Baals, R. Labouvie, A.B.Bhattacherjee, A. Pelster, and H. Ott: Measuring Finite-Range Phase Coherencein an Optical Lattice Using Talbot Interferometry; Nature Communications 8,15601/1-8 (2017), arXiv:1611.08430.