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Recently, Zhong et al. [Phys. Rev. A 87, 022337(2013)] investigated the dynamics of quantum Fisher information (QFI) in the presence of decoherence. We here reform their results and propose two schemes to enhance and preserve the QFIs for a…

Quantum Physics · Physics 2016-10-28 Youneng Guo , Maofa Fang , Gouyou Wang , Jiang Huang , Ke Zeng

Neural networks are increasingly used to estimate parameters in quantitative MRI, in particular in magnetic resonance fingerprinting. Their advantages over the gold standard non-linear least square fitting are their superior speed and their…

Precise estimation of physical parameters underpins both scientific discovery and technological development. A central goal of quantum metrology and sensing is to exploit quantum resources like entanglement to devise optimal strategies for…

Quantum Physics · Physics 2026-03-09 Zhao-Yi Zhou , Da-Jian Zhang

The problem of estimating multiple loss parameters of an optical system using the most general ancilla-assisted parallel strategy is solved under energy constraints. An upper bound on the quantum Fisher information matrix is derived…

Quantum Physics · Physics 2018-12-12 Ranjith Nair

Quantum multiparameter estimation involves estimating multiple parameters simultaneously and can be more precise than estimating them individually. Our interest here is to determine fundamental quantum limits to the achievable…

Quantum Physics · Physics 2019-03-26 Shibdas Roy

Quantum metrology enhances the sensitivity of parameter estimation using the distinctive resources of quantum mechanics such as entanglement. It has been shown that the precision of estimating an overall multiplicative factor of a…

Quantum Physics · Physics 2016-05-31 Shengshi Pang , Todd A. Brun

Variational hybrid quantum-classical optimization represents one of the most promising avenue to show the advantage of nowadays noisy intermediate-scale quantum computers in solving hard problems, such as finding the minimum-energy state of…

Quantum Physics · Physics 2020-11-18 Laura Gentini , Alessandro Cuccoli , Stefano Pirandola , Paola Verrucchi , Leonardo Banchi

Being infinite dimensional, non-parametric information geometry has long faced an "intractability barrier" due to the fact that the Fisher-Rao metric is now a functional incurring difficulties in defining its inverse. This paper introduces…

Machine Learning · Statistics 2026-01-08 Bing Cheng , Howell Tong

We propose a scheme for parameter estimation with the steady states of non-Hermitian spin chains. The parameters to be estimated are encoded in the system via the external magnetic field that imposed on the first site of the chain. We…

Quantum Physics · Physics 2022-06-07 Huiqin Zhang , Jiasen Jin

Noisy Intermediate-Scale Quantum computers are expected to be available this year. It is proposed to exploit such a device for decision making under uncertainty. The probabilistic character of quantum mechanics reflects this uncertainty.…

Quantum Physics · Physics 2019-11-15 H. W. L. Naus

This paper explores as didactically as possible the fundamental principles of both classical and quantum metrology, focusing on the Cram\'er-Rao Bound and how it defines the maximum precision in parameter estimation, taking into account…

Quantum Physics · Physics 2024-12-13 Leonardo A. M. Souza

We investigate the problem of estimating simultaneously multiple parameters encoded in the shape of the modes on which the light is expanded. For this, we generalize the mode-encoded parameter estimation theory as introduced in Ref.[1] to a…

Quantum Physics · Physics 2025-05-23 Alexander Boeschoten , Giacomo Sorelli , Manuel Gessner , Claude Fabre , Nicolas Treps

In this article we derive a measure of quantumness in quantum multi-parameter estimation problems. We can show that the ratio between the mean Uhlmann Curvature and the Fisher Information provides a figure of merit which estimates the…

Quantum Physics · Physics 2020-01-01 Angelo Carollo , Bernardo Spagnolo , Alexander A. Dubkov , Davide Valenti

The quantum Fisher information (QFI) represents a fundamental concept in quantum physics. On the one hand, it quantifies the metrological potential of quantum states in quantum-parameter-estimation measurements. On the other hand, it is…

Achieving quantum-enhanced performances when measuring unknown quantities requires developing suitable methodologies for practical scenarios, that include noise and the availability of a limited amount of resources. Here, we report on the…

Quantum Fisher Information (QFI) can be used to quantify how sensitive a quantum state reacts to changes in its variational parameters, making it a natural diagnostic for algorithms such as the Quantum Approximate Optimization Algorithm…

Quantum Physics · Physics 2026-05-08 Brian García Sarmina , Jorge Saavedra Benavides , Guo-Hua Sun , Shi-Hai Dong

Quantum systems that undergo quantum phase transitions exhibit divergent susceptibility and can be exploited as probes to estimate physical parameters. We generalize the dynamic framework for criticality-enhanced quantum sensing by the…

Quantum Physics · Physics 2023-03-01 Xin Zhu , Jia-Hao Lü , Wen Ning , Fan Wu , Li-Tuo Shen , Zhen-Biao Yang , Shi-Biao Zheng

Hybrid approaches that combine data-driven learning with physics-based insight have shown promise for improving the reliability of industrial condition monitoring. This work develops a hybrid condition monitoring framework that integrates…

Machine Learning · Computer Science 2026-04-14 Maryam Ahang , Todd Charter , Masoud Jalayer , Homayoun Najjaran

We demonstrate that memory in an $N$-qubit system subjected to decoherence, is a potential resource for the slow-down of the entanglement decay. We show that this effect can be used to retain the sub shot-noise sensitivity of the parameter…

Quantum Physics · Physics 2014-12-17 P. Szankowski , M. Trippenbach , J. Chwedenczuk

Quantum machine learning models that leverage quantum circuits as quantum feature maps (QFMs) are recognized for their enhanced expressive power in learning tasks. Such models have demonstrated rigorous end-to-end quantum speedups for…

Quantum Physics · Physics 2026-04-29 Nasa Matsumoto , Quoc Hoan Tran , Koki Chinzei , Yasuhiro Endo , Hirotaka Oshima