Xiaoliang Qi (SIMES Friday Seminar)

Date(s) - May 16 2014
11:00 AM - 12:00 PM

Shasta Room, Bldg. 40, Room 361


Genons: A new twist on topologically ordered states

Xiaoliang Qi
Physics Department, Stanford University

Topologically ordered states are quantum states of matter with various exotic properties such as topological ground state degeneracy, and quasiparticles with fractional quantum numbers and fractional statistics. In this talk, I will describe a new aspect of topologically ordered states—the twist defects. Twist defects are extrinsic point defects in a topologically ordered state which couples to the topological properties of the state. A simple example is a branchcut point in a bilayer system, around which the two layers are exchanged. Such defects, named as “genons”, turns out to have rich topological properties, and may be realizable in several physical systems. The concept of genons and twist defects provides a new approach to topological states of matter and topological quantum computation. In this talk I will summarize the basic properties of genons and more general twist defects, and discuss the proposal of realizing genons in conventional bilayer quantum Hall states. I will also discuss a theoretical application of genons as “slave-particles” which help us to find new types of spin models with possible non-Abelian topological phases