Masaki Oshikawa

Sep 27, 2024 | link.aps.org | Yuan Yao |Shanghai Jiao Tong |Linhao Li |Masaki Oshikawa

We study quantum many-body systems in the presence of an exotic antiunitary translation or inversion symmetry involving time reversal. Based on a symmetry-twisting method and spectrum robustness, we propose that a half-integer spin chain that respects any of these two antiunitary crystalline symmetries in addition to the discrete Z2×Z2 global spin-rotation symmetry must either be gapless or possess degenerate ground states.