Quantum discord in the ground state of spin chains
Abstract
The ground state of a quantum spin chain is a natural playground for investigating correlations. Nevertheless, not all correlations are genuinely of quantum nature. Here we review the recent progress to quantify the 'quantumness' of the correlations throughout the phase diagram of quantum spin systems. Focusing to one spatial dimension, we discuss the behavior of quantum discord close to quantum phase transitions. In contrast to the two-spin entanglement, pairwise discord is effectively long-ranged in critical regimes. Besides the features of quantum phase transitions, quantum discord is especially feasible to explore the factorization phenomenon, giving rise to nontrivial ground classical states in quantum systems. The effects of spontaneous symmetry breaking are also discussed as well as the identification of quantum critical points through correlation witnesses.
Keywords
Cite
@article{arxiv.1208.4817,
title = {Quantum discord in the ground state of spin chains},
author = {Marcelo S. Sarandy and Thiago R. de Oliveira and Luigi Amico},
journal= {arXiv preprint arXiv:1208.4817},
year = {2015}
}
Comments
v2: published version. 24 pages, 12 figures. Special issue "Classical Vs Quantum correlations in composite systems" edited by L. Amico, S. Bose, V. Korepin and V. Vedral