Construct order parameters from the reduced density matrix spectra

Journal Article · Sun Sep 15 00:00:00 EDT 2013 · Annals of Physics (New York)

DOI:https://doi.org/10.1016/J.AOP.2013.05.014· OSTI ID:22220775

Gu, Shi-Jian ^[1]; Yu, Wing Chi ^[1]; Lin, Hai-Qing ^[1]

---

1. Department of Physics and ITP, The Chinese University of Hong Kong, Hong Kong (China)

In this paper, we try to establish a connection between a quantum information concept, i.e., the mutual information, and the conventional order parameter in condensed matter physics. We show that non-vanishing mutual information between two subsystems separated by a long distance means the existence of long-range orders in the system. By analyzing the spectra of the reduced density matrices that are used to calculate the mutual information, we show how to derive the local order operators that identify various ordered phases in condensed matter physics. -- Highlights: •Discussed the relation between long-range order and the mutual information (MI). •Pointed out how to check the existence of long-range order from MI. •Proposed a scheme to derive the diagonal and off-diagonal order parameter. •Gave three examples to show the effectiveness of the scheme.

• OSTI ID: 22220775
• Journal Information: Annals of Physics (New York), Vol. 336; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-4916
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DENSITY MATRIX
MATTER
ORDER PARAMETERS
QUANTUM INFORMATION
SPECTRA