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Phys. Rev. A 77, 022327 (2008) [6 pages]

Quantum Chernoff bound metric for the XY model at finite temperature

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Damian F. Abasto1,*, N. Tobias Jacobson1,†, and Paolo Zanardi1,2
1Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
2Institute for Scientific Interchange, Viale Settimio Severo 65, I-10133 Torino, Italy

Received 15 November 2007; published 28 February 2008

We explore the finite-temperature phase diagram of the anisotropic XY spin chain using the quantum Chernoff bound metric on thermal states. The analysis of the metric elements allows one to easily identify, in terms of different scaling with temperature, quasiclassical and quantum-critical regions. These results extend recent ones obtained using the Bures metric and show that different information-theoretic notions of distance can carry the same sophisticated information about the phase diagram of an interacting many-body system featuring quantum-critical points.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevA.77.022327
DOI:
10.1103/PhysRevA.77.022327
PACS:
03.67.−a, 03.65.Ud, 64.70.Tg, 24.10.Cn

*abasto@usc.edu

ntj@usc.edu