Abstract
We show the presence of universal features in the entanglement entropy of regularized boundary states for conformal field theories on a circle when the reduced density matrix is obtained by tracing over right- or left-moving modes. We derive a general formula for the left-right entanglement entropy in terms of the central charge and the modular matrix of the theory. When the state is chosen to be an Ishibashi state, this measure of entanglement is shown to precisely reproduce the spatial entanglement entropy of a topological quantum field theory. We explicitly evaluate the left-right entanglement entropies for the Ising model, the tricritical Ising model and the Wess-Zumino-Witten model as examples.
- Received 27 April 2015
DOI:https://doi.org/10.1103/PhysRevLett.115.131602
© 2015 American Physical Society