Entanglement entropy of excited states
Abstract
We study the entanglement entropy of a block of contiguous spins in excited states of spin chains. We consider the XY model in a transverse field and the XXZ Heisenberg spin chain. For the latter, we developed a numerical application of the algebraic Bethe ansatz. We find two main classes of states with logarithmic and extensive behavior in the dimension of the block, characterized by the properties of excitations of the state. This behavior can be related to the locality properties of the Hamiltonian having a given state as the ground state. We also provide several details of the finite size scaling.
 Publication:

Journal of Statistical Mechanics: Theory and Experiment
 Pub Date:
 October 2009
 DOI:
 10.1088/17425468/2009/10/P10020
 arXiv:
 arXiv:0909.1999
 Bibcode:
 2009JSMTE..10..020A
 Keywords:

 Condensed Matter  Statistical Mechanics;
 Condensed Matter  Strongly Correlated Electrons;
 High Energy Physics  Theory;
 Quantum Physics
 EPrint:
 37 pages, 10 figures