Entanglement in XY Spin Chain
Quantum Physics
2009-11-10 v4 Statistical Mechanics
Exactly Solvable and Integrable Systems
Abstract
We consider the ground state of the XY model on an infinite chain at zero temperature. Following Bennett, Bernstein, Popescu, and Schumacher we use entropy of a sub-system as a measure of entanglement. Vidal, Latorre, Rico and Kitaev conjectured that von Neumann entropy of a large block of neighboring spins approaches a constant as the size of the block increases. We evaluated this limiting entropy as a function of anisotropy and transverse magnetic field. We used the methods based on integrable Fredholm operators and Riemann-Hilbert problem. The entropy is singular at phase transitions.
Cite
@article{arxiv.quant-ph/0409027,
title = {Entanglement in XY Spin Chain},
author = {A. R. Its and B. -Q. Jin and V. E. Korepin},
journal= {arXiv preprint arXiv:quant-ph/0409027},
year = {2009}
}
Comments
8 pages and 2 figures