Entanglement Entropy and Quantum Phase Transition in the O(N) σmodel
Abstract
We investigate how entanglement entropy behaves in a nonconformal scalar field system with a quantum phase transition, by the replica method. We study the σmodel in 3+1 dimensions which is O(N) symmetric as the mass squared parameter μ^{2} is positive, and undergoes spontaneous symmetry breaking while μ^{2} becomes negative. The area law leading divergence of the entanglement entropy is preserved in both of the symmetric and the broken phases. The spontaneous symmetry breaking changes the subleading divergence from log to log squared, due to the cubic interaction on the cone. At the leading order of the coupling constant expansion, the entanglement entropy reaches a cusped maximum at the quantum phase transition point μ^{2} = 0, and decreases while μ^{2} is tuned away from 0 into either phase.
 Publication:

Journal of High Energy Physics
 Pub Date:
 July 2021
 DOI:
 10.1007/JHEP07(2021)201
 arXiv:
 arXiv:1411.2916
 Bibcode:
 2021JHEP...07..201C
 Keywords:

 Global Symmetries;
 Sigma Models;
 High Energy Physics  Theory
 EPrint:
 36 pp., 5 figures