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Title: Mixed-state fidelity and quantum criticality at finite temperature

Abstract

We extend to finite temperature the fidelity approach to quantum phase transitions (QPTs). This is done by resorting to the notion of mixed-state fidelity that allows one to compare two density matrices corresponding to two different thermal states. By exploiting the same concept we also propose a finite-temperature generalization of the Loschmidt echo. Explicit analytical expressions of these quantities are given for a class of quasifree fermionic Hamiltonians. A numerical analysis is performed as well showing that the associated QPTs show their signatures in a finite range of temperatures.

Authors:
 [1];  [2]; ;  [3];  [4]
  1. Institute for Scientific Interchange, Villa Gualino, Viale Settimio Severo 65, I-10133 Torino (Italy)
  2. (United States)
  3. Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100080 (China)
  4. Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou 310027 (China)
Publication Date:
OSTI Identifier:
20982240
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.032109; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPARATIVE EVALUATIONS; CRITICALITY; DENSITY MATRIX; FERMIONS; HAMILTONIANS; MIXED STATE; NUMERICAL ANALYSIS; PHASE TRANSFORMATIONS

Citation Formats

Zanardi, Paolo, Department of Physics and Astronomy, University of Southern California Los Angeles, California 90089-0484, Quan, H. T., Sun, C. P., and Wang, Xiaoguang. Mixed-state fidelity and quantum criticality at finite temperature. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.032109.
Zanardi, Paolo, Department of Physics and Astronomy, University of Southern California Los Angeles, California 90089-0484, Quan, H. T., Sun, C. P., & Wang, Xiaoguang. Mixed-state fidelity and quantum criticality at finite temperature. United States. doi:10.1103/PHYSREVA.75.032109.
Zanardi, Paolo, Department of Physics and Astronomy, University of Southern California Los Angeles, California 90089-0484, Quan, H. T., Sun, C. P., and Wang, Xiaoguang. Thu . "Mixed-state fidelity and quantum criticality at finite temperature". United States. doi:10.1103/PHYSREVA.75.032109.
@article{osti_20982240,
title = {Mixed-state fidelity and quantum criticality at finite temperature},
author = {Zanardi, Paolo and Department of Physics and Astronomy, University of Southern California Los Angeles, California 90089-0484 and Quan, H. T. and Sun, C. P. and Wang, Xiaoguang},
abstractNote = {We extend to finite temperature the fidelity approach to quantum phase transitions (QPTs). This is done by resorting to the notion of mixed-state fidelity that allows one to compare two density matrices corresponding to two different thermal states. By exploiting the same concept we also propose a finite-temperature generalization of the Loschmidt echo. Explicit analytical expressions of these quantities are given for a class of quasifree fermionic Hamiltonians. A numerical analysis is performed as well showing that the associated QPTs show their signatures in a finite range of temperatures.},
doi = {10.1103/PHYSREVA.75.032109},
journal = {Physical Review. A},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}