Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 53: Low-Dimensional Systems: 1D - Theory

TT 53.1: Vortrag

Mittwoch, 9. März 2016, 15:00–15:15, H23

Topological phases and phase transitions of interacting fermions in 1D — •Ruben Verresen — MPI-PKS, Dresden, Germany

Not all phases of matter can be described by local order parameters. One such unconventional class is that of Symmetry Protected Topological (SPT) phases, where the presence of a symmetry and a gap ensures interesting topological effects. Topological insulators are a prominent example, but the landscape of SPTs becomes more interesting when we allow for interactions. Here we focus on 1D fermionic systems. In 2010 it was discovered that if the Hamiltonian conserves fermionic parity and is time reversal invariant, there are exactly eight gapped phases--one being the celebrated Kitaev chain with Majorana edge modes. This analysis led to a general classification of SPT phases. We revisit these unconventional 1D fermionic phases in concrete models, both to discuss the conceptual underpinning of SPTs and to characterize the critical theories when tuning between these eight phases. The latter is of particular interest since the understanding of phase transitions between SPTs is still a very young field.