[Phys-seminars] 2017-01-18 Condensed Matter Theory Seminar
smoshe
smoshe at bgu.ac.il
Sun Jan 15 15:19:35 IST 2017
Condensed Matter Theory Seminar
DATE: 18-01-17
TIME: 13:30
PLACE: Physics building (#54) room 207
TITLE:
Topological phases of parafermionic chains with symmetries
SPEAKER:
Dganit Meidan, Ben-Gurion University
ABSTRACT/COMMENTS:
We study the topological classification of parafermionic chains in the presence of a modified time reversal symmetry that satisfies T 2 = 1. Such chains can be realized in one dimensional structures embedded in fractionalized two dimensional states of matter, e.g. at the edges of a fractional quantum spin Hall system, where counter propagating modes may be gapped either by back-scattering or by coupling to a superconductor. In the absence of any additional symmetries, a chain of Zm parafermions can belong to one of several distinct phases. We find that when the modified time reversal symmetry is imposed, the classification becomes richer. If m is odd, each of the phases splits into two subclasses. We identify the symmetry protected phase as a Haldane phase that carries a Kramers doublet at each end. When m is even, each phase splits into four subclasses. The origin of this split is in the emergent Majorana fermions associated with even values of m. We demonstrate the appearan
ce of such emergent Majorana zero modes in a system where the constituents particles are either fermions or bosons.
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