On entanglement evolution across defects in critical chains

Viktor Eisler, Ingo Peschel

Published 2012-05-19, updated 2012-06-04Version 2

We consider a local quench where two free-fermion half-chains are coupled via a defect. We show that the logarithmic increase of the entanglement entropy is governed by the same effective central charge which appears in the ground-state properties and which is known exactly. For unequal initial filling of the half-chains, we determine the linear increase of the entanglement entropy.