Universal entanglement of singular surfaces

In general three-dimensional conformal field theories (CFTs), the entanglement entropy receives a logarithmic contribution whenever the entangling surface contains a sharp corner of opening angle theta. Such contribution is controlled by a regulator-independent function a(theta) which vanishes as a(theta) = sigma(theta - pi)(2) in the smooth-surface limit (theta -> pi). We review our recent conjecture that for general three-dimensional CFTs, this corner coefficient s is determined by CT, the coefficient appearing in the two-point function of the stress tensor through the relation sigma/CT = pi(2)/24. We also comment on the extension of this conjecture to general Renyi entropies and higher-dimensional CFTs.