Dr. Masatoshi Sato (ISSP, Univ. of Tokyo)
"Topological Superconductors and Majorana Fermions"
When a topological order is realized in a certain class of superconductors, it supports Majorana fermions on the edge or in the vortex core. Vortices with Majorana fermion modes are neither fermions nor bosons but non-Abelian anyons, obeying the non-Abelian statistics for which the exchange operations of particles are not commutative. Because of this remarkable feature, Majorana fermions play an important role for the realization of fault-tolerant topological quantum computation. In this talk, I would like to report our recent work on Majorana fermions and non-Abelian anyons in topological superconductors. Until recently, only a few of spin-triplet superconducting states, such as \nu=2/5 fractional quantum Hall states or Sr2RuO4, had been known to exhibit Majorana fermions. In this talk, I show that spin-singlet superconductors also support Majorana fermions if we take into account the spin-orbit interaction. I also discuss that a peculiar flat dispersion Majorana fermion is possible in a certain non-centrosymmetric superconductor. Topological characterization of these Majorana fermions is also argued.