Multipartite entanglement after a quantum quench
Abstract
We study the multipartite entanglement of a quantum many-body system undergoing a quantum quench. We quantify multipartite entanglement through the quantum Fisher information (QFI) density and we are able to express it after a quench in terms of a generalized response function. For pure state initial conditions and in the thermodynamic limit, we can express the QFI as the fluctuations of an observable computed in the so-called diagonal ensemble. We apply the formalism to the dynamics of a quantum Ising chain after a quench in the transverse field. In this model the asymptotic state is, in almost all cases, more than two-partite entangled. Moreover, starting from the ferromagnetic phase, we find a divergence of multipartite entanglement for small quenches closely connected to a corresponding divergence of the correlation length.
Cite
@article{arxiv.1701.05883,
title = {Multipartite entanglement after a quantum quench},
author = {Silvia Pappalardi and Angelo Russomanno and Alessandro Silva and Rosario Fazio},
journal= {arXiv preprint arXiv:1701.05883},
year = {2017}
}
Comments
20 pages, 9 figures, un-copyedited version of the article published in Journal of Statistical Mechanics: Theory and Experiment