Speaker
Description
A massless Dirac fermion in 1+1d has axial and vector symmetries whose lattice realization is constrained by the chiral anomaly. In this talk, we will discuss lattice realizations of these symmetries governed by the Onsager algebra. The resulting Onsager symmetry has a lattice anomaly that becomes the chiral anomaly in the continuum limit. We will show that the lattice anomaly of the Onsager symmetry is order 2, which is consistent with, but distinct from, the infinite-order chiral anomaly in the continuum. This mismatch is resolved, however, by imposing a lattice CPT symmetry. With the lattice CPT symmetry enforced, the lattice anomaly is enhanced from order two to infinite order, yielding a lattice symmetry structure that more faithfully captures the continuum anomaly. (This talk is based on upcoming work with Elijah Lew-Smith and Shu-Heng Shao).
