Quantum Fisher information as a witness of non-Markovianity and criticality in the spin-boson model

Fuente: arXiv
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Auteurs principaux: Parlato, Daniele, Di Bello, Grazia, Pavan, Fabrizio, De Filippis, Giulio, Perroni, Carmine Antonio
Format: Preprint
Publié: 2025
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author Parlato, Daniele
Di Bello, Grazia
Pavan, Fabrizio
De Filippis, Giulio
Perroni, Carmine Antonio
author_facet Parlato, Daniele
Di Bello, Grazia
Pavan, Fabrizio
De Filippis, Giulio
Perroni, Carmine Antonio
contents The quantum Fisher information, the quantum analogue of the classical Fisher information, is a central quantity in quantum metrology and quantum sensing due to its connection to parameter estimation and fidelity susceptibility. Using numerically exact methods applied to a paradigmatic open quantum system, the spin-boson model, we calculate both static and dynamical quantum Fisher information matrix elements with respect to spin-bath couplings and magnetic field strengths. As the spin-bath interaction increases, we first show that the coupling-coupling matrix elements relative to the ground state of the Hamiltonian are linked to the entanglement growth and signal the Berezinskii-Kosterlitz-Thouless quantum phase transition through their non-monotonic behavior. We also point out that the static quantum Fisher information exhibits a non-perturbative behavior in the zero-coupling limit, which we justify with an analytic argument. Furthermore, we demonstrate that the time-dependent matrix elements can reveal non-Markovian effects as well as the transition from the coherent to incoherent regime at the Toulouse point, remaining robust under pure dephasing noise. Non-monotonic signatures of the quantum Fisher information matrix reflect changes in quantum resources such as entanglement and coherence, quantify non-Markovian behavior, and enable criticality-enhanced quantum sensing, thereby shedding light on key features of open quantum systems.
format Preprint
id arxiv_https___arxiv_org_abs_2508_16413
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantum Fisher information as a witness of non-Markovianity and criticality in the spin-boson model
Parlato, Daniele
Di Bello, Grazia
Pavan, Fabrizio
De Filippis, Giulio
Perroni, Carmine Antonio
Quantum Physics
Statistical Mechanics
Computational Physics
The quantum Fisher information, the quantum analogue of the classical Fisher information, is a central quantity in quantum metrology and quantum sensing due to its connection to parameter estimation and fidelity susceptibility. Using numerically exact methods applied to a paradigmatic open quantum system, the spin-boson model, we calculate both static and dynamical quantum Fisher information matrix elements with respect to spin-bath couplings and magnetic field strengths. As the spin-bath interaction increases, we first show that the coupling-coupling matrix elements relative to the ground state of the Hamiltonian are linked to the entanglement growth and signal the Berezinskii-Kosterlitz-Thouless quantum phase transition through their non-monotonic behavior. We also point out that the static quantum Fisher information exhibits a non-perturbative behavior in the zero-coupling limit, which we justify with an analytic argument. Furthermore, we demonstrate that the time-dependent matrix elements can reveal non-Markovian effects as well as the transition from the coherent to incoherent regime at the Toulouse point, remaining robust under pure dephasing noise. Non-monotonic signatures of the quantum Fisher information matrix reflect changes in quantum resources such as entanglement and coherence, quantify non-Markovian behavior, and enable criticality-enhanced quantum sensing, thereby shedding light on key features of open quantum systems.
title Quantum Fisher information as a witness of non-Markovianity and criticality in the spin-boson model
topic Quantum Physics
Statistical Mechanics
Computational Physics
url https://arxiv.org/abs/2508.16413