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The tomographic picture of quantum mechanics has brought the description of quantum states closer to that of classical probability and statistics. On the other hand, the geometrical formulation of quantum mechanics introduces a metric…

We consider estimating the magnitude of a monochromatic AC signal that couples to a two-level sensor. For any detection protocol, the precision achieved depends on the signal's frequency and can be quantified by the quantum Fisher…

In this paper, we investigate steered quantum coherence, i.e., the $l_1$ norm of steered coherence and the relative entropy of steered coherence, and the quantum Fisher information in the Gibbs state of two-qubit $XXZ$ systems. Their…

Quantum Physics · Physics 2023-12-18 Biao-Liang Ye , Yao-Kun Wang , Shao-Ming Fei

A two-spin-1/2 Heisenberg XYZ model with Dzyaloshinsky--Moriya (DM) and Kaplan--Shekhtman--Entin-Wohlman--Aharony (KSEA) interactions in the presence of an inhomogeneous external magnetic field is considered at thermal equilibrium. Its…

Quantum Physics · Physics 2023-05-16 M. A. Yurischev , Saeed Haddadi

Genuine multipartite entanglement plays important roles in quantum information processing. The detection of genuine multipartite entanglement has been long time a challenging problem in the theory of quantum entanglement. We propose a…

Quantum Physics · Physics 2020-07-28 Long-Mei Yang , Bao-Zhi Sun , Bin Chen , Shao-Ming Fei , Zhi-Xi Wang

A central task in quantum metrology is to exploit quantum correlations to outperform classical sensitivity limits. Metrologically useful entanglement is identified when the quantum Fisher information (QFI) exceeds a separability bound for a…

Quantum Physics · Physics 2025-03-11 Satoya Imai , Augusto Smerzi , Luca Pezzè

In recent years, significant progress has been made in utilizing the divergence of spectrum response rate at the exceptional point (EP) for sensing in classical systems, while the use and characterization of quantum EPs for sensing have…

Quantum Physics · Physics 2024-04-08 Chun-Hui Liu , Fu Li , Shengwang Du , Jianming Wen , Lan Yang , Chuanwei Zhang

Quantum mechanics predicts that measurements of incompatible observables carry a minimum uncertainty which is independent of technical deficiencies of the measurement apparatus or incomplete knowledge of the state of the system. Nothing yet…

Quantum Physics · Physics 2013-06-14 Davide Girolami , Tommaso Tufarelli , Gerardo Adesso

We investigate and compare three distinguished geometric measures of bipartite quantum correlations that have been recently introduced in the literature: the geometric discord, the measurement-induced geometric discord, and the discord of…

Quantum Physics · Physics 2016-05-26 Wojciech Roga , Dominique Spehner , Fabrizio Illuminati

Quantum discord is a measure of quantum correlations beyond the entanglement-separability paradigm. It is conceptualized by using the von Neumann entropy as a measure of disorder. We introduce a class of quantum correlation measures as…

Quantum Physics · Physics 2015-08-07 Avijit Misra , Anindya Biswas , Arun K. Pati , Aditi Sen De , Ujjwal Sen

This paper continues on the program of developing a relativistic quantum information theory in terms of unequal-time correlation functions in quantum field theory (QFT)[arXiv:2208.03696]. Here, we focus on the definition of quantum…

Quantum Physics · Physics 2024-11-19 Charis Anastopoulos , Konstantina Savvidou

Quantum correlation includes quantum entanglement and quantum discord. Both entanglement and discord have a common necessary condition--------quantum coherence or quantum superposition. In this paper, we attempt to give an alternative…

Quantum Physics · Physics 2014-09-23 Chang-shui Yu , Yang Zhang , Haiqing Zhao

In this work we analyze a non-commutativity measure of quantum correlations recently proposed by Y. Guo [Sci. Rep. 6, 25241 (2016)]. By recourse to a systematic survey of a two-qubit system, we detected an undesirable behavior of such a…

Quantum Physics · Physics 2017-08-25 A. P. Majtey , D. Bussandri , T. M. Osán , P. W. Lamberti , A. Valdés-Hernández

The quantum Fisher information (FI), when applied to the estimation of the separation of two point sources, has been shown to be non-zero in cases where the coherence between the sources are known. Although it has been claimed that…

Optics · Physics 2020-12-16 Kevin Liang , S. A. Wadood , A. N. Vamivakas

We propose a quantum metrology protocol based on a two-step joint evolution of the probe system and an ancillary qubit and quantum measurement. With a proper initial state of the ancillary qubit and an optimized evolution time, the quantum…

Quantum Physics · Physics 2025-01-06 Peng Chen , Jun Jing

The net Fisher information measure, defined as the product of position and momentum Fisher information measures and derived from the non-relativistic Hartree-Fock wave functions for atoms with Z=1-102, is found to correlate well with the…

Quantum Physics · Physics 2015-06-26 K. D. Sen , C. P. Panos , K. Ch. Chatzisavvas , Ch. C. Moustakidis

A long-standing debate on Unruh effect is about its obscure thermal nature. In this Letter, we use quantum Fisher information (QFI) as an effective probe to explore the thermal nature of Unruh effect from both local and global perspectives.…

High Energy Physics - Theory · Physics 2022-03-02 Jun Feng , Jing-Jun Zhang

In quantum information theory, Fisher Information is a natural metric on the space of perturbations to a density matrix, defined by calculating the relative entropy with the unperturbed state at quadratic order in perturbations. In…

High Energy Physics - Theory · Physics 2016-05-25 Nima Lashkari , Mark Van Raamsdonk

Analytic quantifiers of the symmetric quantum discord for two-qubit X type states and block-diagonal states and the symmetric measurement induced nonlocality for any two qubit states are established on the basis of the quantum skew…

Quantum Physics · Physics 2019-03-19 Li-qiang Zhang , Si-ren Yang , Chang-shui Yu

We generalize the quantum Fisher information flow proposed by Lu \textit{et al}. [Phys. Rev. A \textbf{82}, 042103 (2010)] to the multi-parameter scenario from the information geometry perspective. A measure named the \textit{intrinsic…

Quantum Physics · Physics 2021-02-22 Haijun Xing , Libin Fu
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