Quantum discord in finite XY chains
Abstract
We examine the quantum discord between two spins in the exact ground state of finite spin 1/2 arrays with anisotropic XY couplings in a transverse field B. It is shown that in the vicinity of the factorizing field B_s, the discord approaches a common finite non-negligible limit which is independent of the pair separation and the coupling range. An analytic expression of this limit is provided. The discord of a mixture of aligned pairs in two different directions, crucial for the previous results, is analyzed in detail, including the evaluation of coherence effects, relevant in small samples and responsible for a parity splitting at B_s. Exact results for finite chains with first neighbor and full range couplings and their interpretation in terms of such mixtures are provided.
Keywords
Cite
@article{arxiv.1105.0027,
title = {Quantum discord in finite XY chains},
author = {L. Ciliberti and R. Rossignoli and N. Canosa},
journal= {arXiv preprint arXiv:1105.0027},
year = {2015}
}
Comments
9 pages, 6 figures