356 citations · 2.7k across the 47 of their papers we have counts for
6 papers · 1 filter
Anomalous Symmetries End at the Boundary
Ryan Thorngren, Yifan Wang
A global symmetry of a quantum field theory is said to have an 't Hooft anomaly if it cannot be promoted to a local symmetry of a gauged theory. In this paper, we show that the ano…
Intrinsically Gapless Topological Phases
Ryan Thorngren, Ashvin Vishwanath, Ruben Verresen
Topology in quantum matter is typically associated with gapped phases. For example, in symmetry protected topological (SPT) phases, the bulk energy gap localizes edge modes near th…
Non-Fermi liquids as ersatz Fermi liquids: general constraints on compressible metals
Dominic V. Else, Ryan Thorngren, T. Senthil
A system with charge conservation and lattice translation symmetry has a well-defined filling , which is a real number representing the average charge per unit cell. We show tha…
Berry Phase in Quantum Field Theory: Diabolical Points and Boundary Phenomena
Po-Shen Hsin, Anton Kapustin, Ryan Thorngren
We study aspects of Berry phase in gapped many-body quantum systems by means of effective field theory. Once the parameters are promoted to spacetime-dependent background fields, s…
Bulk Anyons as Edge Symmetries: Boundary Phase Diagrams of Topologically Ordered States
Tsuf Lichtman, Ryan Thorngren, Netanel H. Lindner +2
We study effectively one-dimensional systems that emerge at the edge of a two-dimensional topologically ordered state, or at the boundary between two topologically ordered states.…
TQFT, Symmetry Breaking, and Finite Gauge Theory in 3+1D
Ryan Thorngren
We derive a canonical form for 2-group gauge theory in 3+1D which shows they are either equivalent to Dijkgraaf-Witten theory or to the so-called "EF1" topological order of Lan-Wen…