A note on electromagnetic edge modes

Abstract

We give an intuitive identification for the electromagnetic edge modes as virtual spinon excitations in quantum spin liquids. Depending on the statistics, these edge modes could be effectively described by the $\beta \gamma$ or $bc$ conformal field theory. As an example, we show how such a description may reconcile the discrepancy on the logarithmic coefficient of the entanglement entropy on a sphere. Also we give some comments on the possibility of a topological term in the entanglement entropy.

Comments: 10 pages; corrected the statements on the trivial and magnetic center, added comments on the topological term