  We calculate numerically the logarithmic contribution to the entanglement
entropy of a cylindrical region in three spatial dimensions for a Maxwell
field. Our result does not agree with the analytical predictions concerning any
conformal field theory in four dimensions according to which the coefficient is
universal and proportional to the type c conformal anomaly. In cylindrical
coordinates the problem decomposes into one dimensional ones along the radial
coordinate for each angular momentum. The entanglement entropy of a Maxwell
field is equivalent to the one of two identical decoupled scalars with an extra
self interaction term.
