Entanglement entropy of evolving wormholes

Abstract

We compute the entanglement entropy of a discretized scalar field in the fixed spacetime background of an evolving wormhole. Evolving wormholes are a class of time dependent and spherically symmetric wormhole geometries. In both expanding and contracting models, we find dynamically generated entanglement. Asymptotically far from the wormhole throat, the entanglement entropy is well described by the leading term in the area law, although its coefficient can depend sensitively on the value of the UV cutoff. As the UV cutoff is decreased, the coefficient becomes progressively less sensitive to the cutoff, providing numerical evidence that it approaches a cutoff-independent value in the continuum limit. Near the throat, we find a double-dip structure in the entanglement entropy which cannot be described by the leading and logarithmic contributions to the area law.