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Quantum Fisher information (QFI) is a novel measure of multipartite quantum entanglement that can be measured in inelastic neutron scattering experiments on quantum magnets. In this work, we demonstrate that the QFI can be used to…

Strongly Correlated Electrons · Physics 2025-10-17 Chengkang Zhou , Zhengbang Zhou , Félix Desrochers , Yong Baek Kim , Zi Yang Meng

We quantify the quantum correlations between two accelerated detectors coupled to a scalar field in a cavity. It has been realized that an accelerated detector will experience a thermal bath, which is termed the Unruh effect. We examine the…

Quantum Physics · Physics 2021-12-22 He Wang , Jin Wang

Quantum Fisher Information (QFI) is a fundamental quantity in quantum parameter estimation theory, characterizing the ultimate precision bound of parameter estimation. In this work, we investigate QFI for quantum states in non-Hermitian…

Quantum Physics · Physics 2025-05-27 L. H. Wei , H. J. Xing , L. B. Fu , H. D. Liu

By using the non-Markovian master equation, we investigate the effect of the cavity and the environment on the quantum Fisher information (QFI) of an atom qubit system in a dissipation cavity. We obtain the formulae of QFI for two different…

Quantum Physics · Physics 2019-05-17 Danping Lin , Yu Liu , Hong-Mei Zou

We revisit the Unruh effect within a general framework based on direct, probability-level calculations. We rederive the transition rate of a uniformly accelerating Unruh-DeWitt monopole detector coupled to a massive scalar field, from both…

High Energy Physics - Theory · Physics 2025-01-13 Robert Dickinson , Jeff Forshaw , Ross Jenkinson , Peter Millington

In this paper we analyze the interaction of a uniformly accelerated detector with a quantum field in (3+1)D spacetime, aiming at the issue of how kinematics can render vacuum fluctuations the appearance of thermal radiance in the detector…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Shih-Yuin Lin , B. L. Hu

We consider the general problem of estimating an unknown control parameter of an open quantum system. We establish a direct relation between the evolution of both system and environment and the precision with which the parameter can be…

Quantum Physics · Physics 2016-02-10 Katarzyna Macieszczak , Madalin Guta , Igor Lesanovsky , Juan P. Garrahan

Quantum Fisher information (QFI) is an important feature for the precision of quantum parameter estimation based on the quantum Cram\'er-Rao inequality. When the quantum state satisfies the von Neumann-Landau equation, the local quantum…

Quantum Physics · Physics 2018-02-27 Shao-xiong Wu , Yang Zhang , Chang-shui Yu

It is shown that the Unruh effect, i.e. the increase in temperature indicated by a uniformly accelerated thermometer in an inertial vacuum state of a quantum field, cannot be interpreted as the result of an exchange of heat with a…

General Relativity and Quantum Cosmology · Physics 2016-03-08 Detlev Buchholz , Rainer Verch

We study the estimation of parameters in a quantum metrology scheme based on entangled many-body Unruh-DeWitt detectors. It is found that the precision for the estimation of Unruh effect can be enhanced via initial state preparations and…

General Relativity and Quantum Cosmology · Physics 2020-02-04 Jieci Wang , Li Zhang , Songbai Chen , Jiliang Jing

In estimating an unknown parameter of a quantum state the quantum Fisher information (QFI) is a pivotal quantity, which depends on the state and its derivate with respect to the unknown parameter. We prove the continuity property for the…

Quantum Physics · Physics 2019-09-16 A. T. Rezakhani , M. Hassani , S. Alipour

The density-density response in optimally doped Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ has recently been shown to exhibit conformal symmetry. Using, the experimentally inferred conformal dynamic susceptibility, we compute the resultant quantum…

Strongly Correlated Electrons · Physics 2025-03-28 David Bałut , Xuefei Guo , Niels de Vries , Dipanjan Chaudhuri , Barry Bradlyn , Peter Abbamonte , Philip W. Phillips

We use the quantum Fisher information (QFI) to diagnose a dynamical phase transition (DPT) in a closed quantum system, which is usually defined in terms of non-analytic behaviour of a time-averaged order parameter. Employing the…

Quantum Physics · Physics 2021-09-08 Qingze Guan , Robert J. Lewis-Swan

The Unruh effect is the phenomenon that accelerated observers detect particles even when inertial observers experience the vacuum state. In particular, uniformly accelerated observers are predicted to measure thermal radiation that is…

Quantum Physics · Physics 2020-08-06 Luis C. Barbado , Esteban Castro-Ruiz , Luca Apadula , Časlav Brukner

The single-mode Dicke model is well-known to undergo a quantum phase transition from the so-called normal phase to the supperradiant phase (hereinafter called the "superradiant quantum phase transition"). Normally, quantum phase transitions…

Quantum Physics · Physics 2014-07-10 T. L. Wang , L. N. Wu , W. Yang , G. R. Jin , N. Lambert , F. Nori

A uniformly accelerated system will get thermally excited due to interactions with the vacuum fluctuations of the quantum fields. This is the Unruh effect. Also a system accelerated in a circular orbit will be heated, but in this case…

High Energy Physics - Theory · Physics 2007-05-23 Jon Magne Leinaas

The Quantum Fisher information (QFI) quantifies the ultimate precision of estimating a parameter from a quantum state, and can be regarded as a reliability measure of a quantum system as a quantum sensor. However, estimation of the QFI for…

Quantum Physics · Physics 2022-02-03 Jacob L. Beckey , M. Cerezo , Akira Sone , Patrick J. Coles

The Quantum Fisher Information (QFI) plays a crucial role in quantum information theory and in many practical applications such as quantum metrology. However, computing the QFI is generally a computationally demanding task. In this work we…

Quantum Physics · Physics 2021-06-25 M. Cerezo , Akira Sone , Jacob L. Beckey , Patrick J. Coles

The Unruh effect predicts that a uniformly accelerated observer perceives the vacuum seen by an inertial observer as a thermal bath at a temperature proportional to its proper acceleration. This phenomenon is often regarded as a flat…

General Relativity and Quantum Cosmology · Physics 2025-09-23 Yuebing Zhou , Jiawei Hu , Hongwei Yu

It has been proved in the context of quantum fields in Minkowski spacetime that the vacuum state is a thermal state according to uniformly accelerated observers -- a seminal result known as the Unruh effect. Recent claims, however, have…

General Relativity and Quantum Cosmology · Physics 2019-07-16 Cesar A. Uliana Lima , Frederico Brito , José A. Hoyos , Daniel A. T. Vanzella