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Biphoton frequency comb (BFC), which encompasses multiple discrete frequency modes and represents high-dimensional frequency entanglement, is crucial in quantum information processing due to its high information capacity and error…

Quantum Physics · Physics 2025-07-30 Baihong Li , Qi-qi Li , Boxin Yuan , Ruifang Dong , Shougang Zhang , Rui-Bo Jin

In this paper, we study the ground state Quantum Fisher Information (QFI) in one-dimensional spin-1 models, as witness to Multipartite Entanglement. The models addressed are the Bilinear-Biquadratic model, the most general isotropic…

Quantum synchronization has emerged as a crucial phenomenon in quantum nonlinear dynamics with potential applications in quantum information processing. Multiple measures for quantifying quantum synchronization exist. However, there is…

Quantum Physics · Physics 2023-08-02 Yuan Shen , Hong Yi Soh , Leong-Chuan Kwek , Weijun Fan

We investigate the generation of quantum states for precision metrology in noisy two-level systems. These states are obtained by optimizing a variational quantum circuit to maximize the quantum Fisher information (QFI) of the output state…

Quantifying measurement precision in quantum systems is vital for advancing quantum technologies such as sensing, communication, and computation. The quantum Fisher information (QFI) sets the ultimate precision bound in Hermitian systems;…

Quantum Physics · Physics 2026-03-12 Javid Naikoo , Ravindra W. Chhajlany , Jan Kołodyński , Adam Miranowicz

Quantum information theory is the study of the achievable limits of information processing within quantum mechanics. Many different types of information can be accommodated within quantum mechanics, including classical information, coherent…

Quantum Physics · Physics 2007-05-23 M. A. Nielsen

We present a real-time path-integral formulation of the quantum Fisher information for dynamical parameter estimation. For pure states undergoing unitary evolution, we show that the quantum Fisher information can be expressed as a connected…

Quantum Fisher information (QFI) has potential applications in quantum metrology tasks. We investigate QFI when the consecutive actions of a quantum channel on the sequence of qubits have partial classical correlations. Our results showed…

Quantum Physics · Physics 2020-03-09 Ming-Liang Hu , Hui-Fang Wang

Recently, it has been shown that the quantum Fisher information via local observables and via local measurements (i.e., local quantum Fisher information (LQFI)) is a central concept in quantum estimation and quantum metrology and captures…

Quantum Physics · Physics 2019-04-30 A. Slaoui , L. Bakmou , M. Daoud , R. Ahl Laamara

Non-Hermitian quantum metrology, an emerging field at the intersection of quantum estimation and non-Hermitian physics, holds promise for revolutionizing precision measurement. Here, we present a comprehensive investigation of non-Hermitian…

Quantum Physics · Physics 2025-09-17 Xinglei Yu , Xinzhi Zhao , Liangsheng Li , Xiao-Min Hu , Xiangmei Duan , Haidong Yuan , Chengjie Zhang

We prove an extended convexity for quantum Fisher information of a mixed state with a given convex decomposition. This convexity introduces a bound which has two parts: i. classical part associated to the Fisher information of the…

Quantum Physics · Physics 2015-04-09 S. Alipour , A. T. Rezakhani

We consider an instance of black-box quantum metrology in the Gaussian framework, where we aim to estimate the amount of squeezing applied on an input probe, without previous knowledge on the phase of the applied squeezing. By taking the…

Quantum Fisher information is a key concept in the field of quantum metrology, which aims to enhance the parameter accuracy by using quantum resources. In this paper, utilizing a representation of quantum Fisher information for a general…

Quantum Physics · Physics 2015-07-14 Xiao-Xing Jing , Jing Liu , Heng-Na Xiong , Xiaoguang Wang

Entangled systems with large quantum Fisher information (QFI) can be used to outperform the standard quantum limit of the separable systems in quantum metrology. However, the interaction between the system and the environments inevitably…

Quantum Physics · Physics 2016-08-23 Guofeng Zhang , Hanjie Zhu

We investigate dynamical quantum phase transitions (DQPTs) in quantum systems that possess well-defined classical limits, focusing on the spinor Bose-Einstein condensate and the Lipkin-Meshkov-Glick model. We diagnose the DQPTs with the…

Quantum Physics · Physics 2025-07-09 J. Mumford , R. J. Lewis-Swan

We derive a new quantum speed limit (QSL) for open quantum systems governed by Markovian dynamics. By analyzing the time derivative of the Bures angle between the initial pure state and its time-evolved state, we obtain an analytically…

Quantum Physics · Physics 2025-07-04 Kohei Kobayashi

Encoding and manipulation of quantum information by means of topological degrees of freedom provides a promising way to achieve natural fault-tolerance that is built-in at the physical level. We show that this topological approach to…

Quantum Physics · Physics 2009-11-07 Paolo Zanardi , Seth Lloyd

We study the time-dependent quantum Fisher information (QFI) in an open quantum system satisfying the Gorini-Kossakowski-Sudarshan-Lindblad master equation. We also study the dynamics of the system from an effective non-Hermitian dynamics…

Quantum Physics · Physics 2023-06-12 Zain H. Saleem , Anil Shaji , Stephen K. Gray

In open quantum systems, we study the quantum Fisher information of acceleration for a uniformly accelerated two-level atom coupled to fluctuating electromagnetic fields in the Minkowski vacuum. With the time evolution, for the initial atom…

Quantum Physics · Physics 2022-09-27 Mengge Zheng , Baoyuan Yang , Zixu Zhao

Quantum metrology studies the ultimate precision limit of physical quantities by using quantum strategy. In this paper we apply the quantum metrology technologies to the relativistic framework for estimating the deficit angle parameter of…

Quantum Physics · Physics 2022-08-11 Ying Yang , Jiliang Jing , Zehua Tian