Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 82: Topological Insulators II (joint session TT/MA)

TT 82.8: Vortrag

Donnerstag, 15. März 2018, 11:30–11:45, A 053

Direct phase transitions between Z_n×Z_n bosonic topological phases in 1+1D — •Julian Bibo¹, Ruben Verresen^1,2, and Frank Pollmann¹ — ¹Technische Universiät München — ²Max-Planck-Institut für komplexe Systeme, Dreseden

Symmetry protected topological (SPT) phases are phases of matter without local order parameters. Instead, they are classified by how a global symmetry G acts projectively on the edges. For G=Z_n×Z_n, there are n−1 non-trivial SPT phases. For n≤4, it has been proven that within a certain class of models there are direct transitions between adjacent phases. For n ≥ 5, however, the expectation was that there are intermediate gapless phases instead of direct transitions. Contrary to this expectation, we argue analytically that there are direct transitions in case n is divisible by 2, 3 or 4. We numerically confirm that these transitions are not fine-tuned.