1:30 pm MCP 201
t Hooft anomaly in $CP^{N-1}$ model without flavor symmetry
Takuya Furusawa, Tokyo Institute of Technology
An 't Hooft anomaly is an obstruction to gauge global symmetries and constrains low-energy behaviors of a system. In this talk, we focus on the 3D $\CP^{N-1}$ model and derive a mixed ’t Hooft anomaly between the refection and magnetic symmetries [1]. To detect the ’t Hooft anomaly, we insert a flux for the reflection symmetry by putting the model on a non-orientable manifold. Then, we find an obstruction to gauge the magnetic symmetry. This anomaly indicates that even when the flavor symmetry is broken, the model doesn't admit a unique gapped groundstate as long as the refection and magnetic symmetries are respected. Contrary to the anomaly found in Ref. [2], our anomaly is intrinsic and must exist even at the lattice scale. Also, we discuss how the anomaly matches in the N\’eel and VBS phases.