Stiefel liquids: possible nonLagrangian quantum criticality from intertwined orders Speaker(s): Chong Wang
Abstract:
We propose a new type of critical quantum liquids, dubbed Stiefel liquids, based on 2+1 dimensional WessZuminoWitten models on target space SO(N)/SO(4). We show that the well known deconfined quantum critical point and U(1) Dirac spin liquid are unified as two special examples of Stiefel liquids, with N = 5 and N = 6, respectively. Furthermore, we conjecture that Stiefel liquids with N > 6 are nonLagrangian, in the sense that the theories do not (at least not easily) admit any weaklycoupled UV completion. Such nonLagrangian states are beyond the paradigm of parton gauge theory familiar in the study of exotic quantum liquids in condensed matter physics. The intrinsic absence of meanfield construction also makes it difficult to decide whether a nonLagrangian state can emerge from a specific UV system (such as a lattice spin system). For this purpose we hypothesize that a quantum state is emergible from a lattice system if its quantum anomalies match with the constraints from the (generalized) LiebSchultzMattis theorems. Based on this hypothesis, we find that some of the nonLagrangian Stiefel liquids can indeed be realized in frustrated quantum spin systems, for example, on triangular or Kagome lattice, through the intertwinement between noncoplanar magnetic orders and valencebondsolid orders. Date: 29/03/2021  12:30 pm
Series: Quantum Matter Frontier Seminars
