Colloquium: Topological quantum field theory in 3+1D and the emergence of quantum gravity

ABSTRACT

Topological quantum field theory (TQFT) is a very powerful theoretical tool to study topological phases and phase transitions. In 2 + 1D, it is well known that the Chern-Simons theory captures all the universal topological data of topological phases, e.g., quasi-particle braiding statistics, chiral central charge and even provides us a deep insight for the nature of topological phase transitions. Recently, topological phases of quantum matter are also intensively studied in 3 + 1D and it has been shown that loop like excitation obeys the so-called three-loop-braiding statistics. In this talk, I will discuss a TQFT framework to understand the quantum statistics of loop like excitation in 3 + 1D. Most surprisingly, this new class of 3+1D TQFT even provides us a new route towards a quantum theory of gravity.

BIOGRAPHY

Education: Ph.D., Physics, 2003-2007, Center for Advanced Study, Tsinghua University; Bachelor, Fundamental Science (Mathematics and Physics), 1999-2003, Tsinghua University. Position: Since 03/2016, Associate Professor, Department of Physics, The Chinese University of Hong Kong; Adjunct Professor, 2015-2020, University of Waterloo; Director's Fellow, 2012-2016, Perimeter Institute (IQIM Fellow 2012-2013, Caltech); Associate Specialist, 2009-2012, Kavli Institute for Theoretical Physics, UCSB; Postdoctoral Fellow, 2007-2009, MIT.