Fisher information in a quantum-critical environment

Journal Article · Sun Aug 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.022306· OSTI ID:21448453

Zhe, Sun ^[1]; Jian, Ma; Xiaoming, Lu; Xiaoguang, Wang ^[2]

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1. Department of Physics, Hangzhou Normal University, Hangzhou 310036 (China)
2. Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou 310027 (China)

We consider a process of parameter estimation in a spin-j system surrounded by a quantum-critical spin chain. Quantum Fisher information lies at the heart of the estimation task. We employ Ising spin chain in a transverse field as the environment which exhibits a quantum phase transition. Fisher information decays with time almost monotonously when the environment reaches the critical point. By choosing a fixed time or taking the time average, one can see the quantum Fisher information presents a sudden drop at the critical point. Different initial states of the environment are considered. The phenomenon that the quantum Fisher information, namely, the precision of estimation, changes dramatically can be used to detect the quantum criticality of the environment. We also introduce a general method to obtain the maximal Fisher information for a given state.

• OSTI ID: 21448453
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 82; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCURACY
ANGULAR MOMENTUM
INFORMATION
MECHANICS
PARTICLE PROPERTIES
PHASE TRANSFORMATIONS
QUANTUM INFORMATION
QUANTUM MECHANICS
QUANTUM STATES
SPIN