SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 47: Quantum-Critical Phenomena

TT 47.10: Vortrag

Donnerstag, 30. März 2023, 12:00–12:15, HSZ 204

Symmetry enriched topological quantum phase transition in projected entangled pair states — •Lukas Haller, Yu-Jie Liu, Wen-Tao Xu, and Frank Pollmann — Department of Physics, Technical University of Munich, 85748 Garching, Germany

Phase transitions between topologically ordered phases can exhibit a rich structure and are generically challenging to study. In this context, we consider the 2D toric code decorated with 1D symmetry protected topological states and construct a family of parametrized projected entangled pair states (PEPS), which describes the ground states of time-reversal (TR) symmetric Hamiltonians. The system can exhibit three distinct phases of matter: (i) A trivial phase; (ii) the toric code phase, where TR symmetry is not fractionalized; (iii) a symmetry enriched topological (SET) phase, where TR symmetry can be fractionalized on anyons. We characterize different phases using topological entanglement entropy and membrane order parameters. By mapping the PEPS to the partition functions of 2D classical models, we show that the trivial phase is separated from the toric code and the SET phases by critical points described by an Ising conformal field theory (CFT) with central charge c=1/2, while the phase transition between the toric code and the SET phase is described by a compactified free-boson CFT with c = 1. The model realizes a direct phase transition between the toric code and the SET phases at a microscopic level.