Decay of Loschmidt Echo Enhanced by Quantum Criticality

2005/09/30 by H. T. Quan, Z. Song, X. F. Liu +4 · 7 citations
Computer Science · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum many-body systems #cond-mat.str-el #quant-ph

paper · pdf · doi:10.1103/physrevlett.96.140604

published as Phys. Rev. Lett. 96, 140604 (2006) · 4 pages, 3 figures

openalex publication_date 2006/04/14 · arxiv created 2006/04/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03

Abstract

We study the transition of a quantum system from a pure state to a mixed one, which is induced by the quantum criticality of the surrounding system E coupled to it. To characterize this transition quantitatively, we carefully examine the behavior of the Loschmidt echo (LE) of E modeled as an Ising model in a transverse field, which behaves as a measuring apparatus in quantum measurement. It is found that the quantum critical behavior of E strongly affects its capability of enhancing the decay of LE: near the critical value of the transverse field entailing the happening of quantum phase transition, the off-diagonal elements of the reduced density matrix describing S vanish sharply.

Citations

• Entanglement versus Correlations in Spin Systems
• Quantum Theory: Concepts and Methods

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