Detail:

Abstract:
　　Phase transitions are both ubiquitous and fascinating. Snow from the sky, a result of a phase transition, is run-of-the-mill in Chicago; however, we remain intrigued when realizing that the beautiful crystals of a snow flake, millimeter in size, grows from the molecular structure at the nano-meter scale. Beyond classical systems, an exponential growth of new symmetry across a phase transition, called inflation, reaches frontier of research on quantum many-body dynamics, as well as in the evolution of early universe.
　　Based on a cesium Bose-Einstein condensate driven across a quantum phase transition, we have observed in the past years a series of interesting phenomena: emergence of topological defects (domain walls), exotic excitations (rotons), as well as the scaling symmetry of temporospatial correlations (Kibble-Zurek mechanism). A fundamental question I will address in this talk is: Is inflation a symmetry-breaking process that follows the second law of thermodynamics, or a quantum coherent process that is unitary and reversible?

Biosketch：
　　Cheng Chin pursued his graduate studies with Steven Chu at Stanford University, receiving his Ph.D. degree in 2001. After a postdoctoral fellowship at Stanford University (2001-2003) and then at Innsbruck University (2003-2005), he joined the faculty of the University of Chicago, where he has been a full professor in the Physics Department, the James Franck Institute, and the Enrico Fermi Institute since 2013. He was a Lise-Meitner Research Fellow (2003-2005), an Alfred P. Sloan Research Fellow (2006-2008), a David and Lucile Packard Fellow (2006-2011) and an Alexander von Humboldt Fellow (2012-2015). He has been honored with the Overseas Chinese Physics Association Outstanding Young Researcher Award (2006), the National Science Foundation CAREER award (2008), the IUPAP Young Scientist Prize in AMO Physics (2008), the APS I.I. Rabi Prize (2011), and the National Taiwan University Distinguished Alumni Award in Physics (2014). Professor Chin is a Fellow of the American Physical Society.