Title: [NCTS-NTU String Theory Seminar] Anomaly matching and symmetry-constrained low-energy properties of 1d quantum many-body systems
Speaker: Prof. Chang-Tse Hsieh (NTU)
Time: June 10, 2022 (Fri) 14:30-15:30
Venue: Online
Meeting Link: https://nationaltaiwanuniversity-zbh.my.webex.com/nationaltaiwanuniversity-zbh.my/j.php?MTID=mf77b1c194d7d57768d2db53dc42697a0

Abstract:
We apply the idea of (’t Hooft) anomaly matching to study 1d quantum many-body systems in the presence of certain crystalline and on-site symmetries. In particular, we identify an indicator for any lattice model that characterizes specific low-energy properties of the system. Such an indicator, if nontrivial, implies either a ground-state degeneracy in a gapped phase or a restriction of the possible universality classes in a critical phase. As examples, we consider translationally invariant fermion systems with U(1) charge conservation and spin systems with spin-rotation symmetries. While agreeing with previous studies of these models, our works provide a systematic and efficient way of constraining the low-energy spectra of quantum many-body systems from symmetries.