Title：Topological order, higher-form symmetry, and dense quark matter
Time：11 a.m.,December 17,2019
Location：725 Conference Room, Communication Building, Shahe Campus
Yuji Hirono received a Ph. D. in Physics from the University of Tokyo in 2014. After that, he worked as a JSPS postdoctoral researcher at Stony Brook University and then as a research associate in Nuclear Theory Group at Brookhaven National Laboratory. Currently he is both the associate professor and the leader of Junior Research Group at Asia Pacific Center for Theoretical Physics in South Korea. Yuji's research interests include QCD, Anomaly-induced chiral effects, heavy-ion collisions, topological defects, complex networks, non-equilibrium phenomena.
The standard way of classifying phases of matter is the use of symmetry breaking patterns. It has been realized later that, if one considers quantum phases of matter, this is not sufficient. Namely, there can be distinct phases without changes of symmetry. Such an order of quantum phases is called a topological order . Identifying the topological structure of phases is important in determining the phase diagram of quantum matter. In this talk, I will review how a topological order can be captured by a generalized form of symmetry, called higher-form symmetries .Then, I’ll discuss an application of this idea to constrain the phase diagram of dense quark matter [3,4].
 X. G. Wen, Int. J. Mod. Phys. B4 (1990) 239.
 D. Gaiotto, A. Kapustin, N. Seiberg, and B. Willett, JHEP 02 (2015) 172.
 Y. Hirono, Y. Tanizaki, Phys. Rev. Lett. 122, 212001(2019).
 Y. Hirono, Y. Tanizaki, JHEP 07 (2019) 062.