  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.
