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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 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

Dephasing is a main noise mechanism that afflicts quantum information, it reduces visibility, and destroys coherence and entanglement. Therefore, it must be reduced, mitigated, and if possible corrected, to allow for demonstration of…

Quantum Physics · Physics 2024-11-19 Zixin Huang , Cosmo Lupo

The sensitivity in optical interferometry is strongly affected by losses during the signal propagation or at the detection stage. The optimal quantum states of the probing signals in the presence of loss were recently found. However, in…

Quantum Fisher information (QFI) is a measure of multipartite quantum entanglement that can be obtained from inelastic neutron scattering data on quantum magnets. In this work, we demonstrate that the QFI can distinguish an unconventional…

Strongly Correlated Electrons · Physics 2026-03-23 Zhengbang Zhou , Chengkang Zhou , Menghan Song , Yong Baek Kim , Zi Yang Meng

We define two ways of quantifying the quantum correlations based on quantum Fisher information (QFI) in order to study the quantum correlations as a resource in quantum metrology. By investigating the hierarchy of measurement-induced Fisher…

Quantum Physics · Physics 2018-03-20 Sunho Kim , Longsuo Li , Asutosh Kumar , Junde Wu

We propose a theoretical scheme to enhance the phase sensitivity by introducing a Kerr nonlinear phase shift into the traditional SU(1,1) interferometer with a coherent state input and homodyne detection. We investigate the realistic…

Quantum Physics · Physics 2021-03-16 Shoukang Chang , Wei Ye , Huan Zhang , Liyun Hu , Jiehui Huang , Sanqiu Liu

The Quantum Fisher Information (QFI) is a geometric measure of state deformation calculated along the trajectory parameterizing an ensemble of quantum states. It serves as a key concept in quantum metrology, where it is linked to the…

Quantum Physics · Physics 2025-12-05 Gabriela Wójtowicz , Susana F. Huelga , Marek M. Rams , Martin B. Plenio

We propose to use the quantum Fisher information in characterizing the information flow of open quantum systems. This information-theoretic approach provides a quantitative measure to statistically distinguish Markovian and non-Markovian…

Quantum Physics · Physics 2010-10-12 Xiao-Ming Lu , Xiaoguang Wang , C. P. Sun

We examine metrological scenarios where the parameter of interest is encoded onto a quantum state through the action of a noisy quantum gate and investigate the ultimate bound to precision by analyzing the behaviour of the Quantum Fisher…

Quantum Physics · Physics 2025-02-18 Giovanni Ragazzi , Simone Cavazzoni , Paolo Bordone , Matteo G. A. Paris

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), as a function of quantum states, measures the amount of information that a quantum state carries about an unknown parameter. The (entanglement-assisted) QFI of a quantum channel is defined to be the…

Quantum Physics · Physics 2021-04-06 Sisi Zhou , Liang Jiang

Precise measurements in optical and atomic systems often rely on differential interferometry. This method allows to handle large and correlated phase noise contributions -- such as environmental vibrations, thermal fluctuations, or…

Quantum Physics · Physics 2025-03-25 Luca Pezzè , Andrea Santoni , Chiara Mazzinghi , Marco Fattori , Augusto Smerzi

We derive an expression for the phase shift of an atom interferometer in a gravitational field taking into account both the finite duration of the light pulses and the effect of a small perturbing potential added to a stronger uniform…

Quantum Physics · Physics 2019-04-02 A. Bertoldi , F. Minardi , M. Prevedelli

Quantum phase estimation (QPE) is the key subroutine of several quantum computing algorithms as well as a central ingredient in quantum computational chemistry and quantum simulation. While QPE strategies have focused on the estimation of a…

Quantum Physics · Physics 2021-07-26 Valentin Gebhart , Augusto Smerzi , Luca Pezzè

In this paper the relation between quantum covariances and quantum Fisher informations are studied. This study is applied to generalize a recently proved uncertainty relation based on quantum Fisher information. The proof given…

Mathematical Physics · Physics 2007-12-10 Paolo Gibilisco , Fumio Hiai , Denes Petz

Quantum State Tomography (QST) has been the traditional method for characterization of an unknown state. Recently, many direct measurement methods have been implemented to reconstruct the state in a resource efficient way. In this letter,…

Quantum Physics · Physics 2020-09-23 Surya Narayan Sahoo , Sanchari Chakraborti , Arun K. Pati , Urbasi Sinha

A new type of quantum entangled interferometer was recently realized that employs parametric amplifiers as the wave splitting and recombination elements. The quantum entanglement stems from the parametric amplifiers, which produce quantum…

Quantum Physics · Physics 2020-09-21 Z. Y. Ou , Xiaoying Li

The comprehension of quantum phase transitions (QPTs) is considered as a critical foothold in the field of many-body physics. Developing protocols to effectively identify and understand QPTs thus represents a key but challenging task for…

Quantum Physics · Physics 2025-04-03 Xiangbei Li , Yaoming Chu , Shaoliang Zhang , Jianming Cai

Multiparameter estimation is a general problem that aims at measuring unknown physical quantities, obtaining high precision in the process. In this context, the adoption of quantum resources promises a substantial boost in the achievable…