English
Related papers

Related papers: Quantum conditional mutual information of W state …

200 papers

Quantum metrology is the state-of-the-art measurement technology. It uses quantum resources to enhance the sensitivity of phase estimation beyond what reachable within classical physics. While single parameter estimation theory has been…

Local or nonlocal character of quantum states can be quantified and is subject to various bounds that can be formulated as complementarity relations. Here, we investigate the local vs. nonlocal character of pure three-qubit states by a…

Quantum Physics · Physics 2008-11-19 Xinhua Peng , Jingfu Zhang , Jiangfeng Du , Dieter Suter

Quantum coherence is an exquisitely quantum phenomenon that depends on both probability amplitudes and relative phases. Standard coherence measures quantify superposition within density matrices but cannot distinguish ensembles that produce…

Quantum Physics · Physics 2026-05-29 Cameron Hahn , Nishan Ranabhat , Fabio Anza

In the last years, a relationship has been established between the quantum Fisher information (QFI) and quantum entanglement. In the case of two-qubit systems, all pure entangled states can be made useful for sub-shot-noise interferometry…

Quantum Physics · Physics 2019-11-11 Stefano Scali , Roberto Franzosi

The difference of quantum mutual information for bipartite system of qubits and minimum taken with respect to local unitary transformation group is introduced as a characteristic of quantum correlations.The two qubits example (and…

Quantum Physics · Physics 2013-06-19 V. I. Manko , Anatoli Yurkevich

Investigating the influence of quantum information (QI) scrambling on quantum correlations in a physical system is an interesting problem. In this article we establish the mathematical connections among the quantifiers known as quantum…

Quantum Physics · Physics 2020-11-10 Kapil K. Sharma , Vladimir P. Gerdt

The development and improvement of analytical methods for evaluating nonclassical correlations is one of the most important tasks in quantum information science. In this paper, we investigate a mixed spin-$(1/2,S)$ system with an arbitrary…

Quantum Physics · Physics 2025-06-06 Saeed Haddadi , Elena I. Kuznetsova , M. A. Yurischev

We derive the compact closed forms of local quantum uncertainty (LQU) and local quantum Fisher information (LQFI) for hybrid qubit-qutrit axially symmetric (AS) states. This allows us to study the quantum correlations in detail and present…

Quantum Physics · Physics 2025-01-31 M. A. Yurischev , Saeed Haddadi , Mehrdad Ghominejad

We analyze the information that one can learn about the state of a quantum two-level system, i.e. a qubit, when probed weakly by a nearby detector. We consider the general case where the qubit Hamiltonian and the qubit's operator probed by…

Quantum Physics · Physics 2009-12-17 S. Ashhab , J. Q. You , Franco Nori

Several applications of quantum machine learning (QML) rely on a quantum measurement followed by training algorithms using the measurement outcomes. However, recently developed QML models, such as variational quantum circuits (VQCs), can be…

Quantum Physics · Physics 2023-08-31 Hossein T. Dinani , Diego Tancara , Felipe F. Fanchini , Ariel Norambuena , Raul Coto

A new measure of information in quantum mechanics is proposed which takes into account that for quantum systems the only feature known before an experiment is performed are the probabilities for various events to occur. The sum of the…

Quantum Physics · Physics 2009-11-06 Caslav Brukner , Anton Zeilinger

While the quantum mutual information is a fundamental measure of quantum information, it is only defined for spacelike-separated quantum systems. Such a limitation is not present in the theory of classical information, where the mutual…

Quantum Physics · Physics 2024-10-04 James Fullwood , Zhen Wu , Arthur J. Parzygnat , Vlatko Vedral

Quantum information refers to the distinctive information-processing properties of quantum systems, which arise when information is stored in or retrieved from nonorthogonal quantum states. More information is required to prepare an…

Quantum Physics · Physics 2007-05-23 Carlton M. Caves , Christopher A. Fuchs

Studying the behavior of quantum information scrambling in various quantum systems is an active area of research. Recently, Sharma et al. [K.K. Sharma, V.P Gerdt, Quantum Inf. Process 20, 195 (2021)] have shown the mathematical connection…

Quantum Physics · Physics 2024-08-27 Kapil K. Sharma , Rishikant Rajdeepak , Ashok Kumar , Prasanta K. Panigrahi

Spontaneous synchronization is a fundamental phenomenon, important in many theoretical studies and applications. Recently this effect has been analyzed and observed in a number of physical systems close to the quantum mechanical regime. In…

Quantum Physics · Physics 2015-06-23 V. Ameri , M. Eghbali-Arani , A. Mari , A. Farace , F. Kheirandish , V. Giovannetti , R. Fazio

Given an unknown quantum state distributed over two systems, we determine how much quantum communication is needed to transfer the full state to one system. This communication measures the "partial information" one system needs conditioned…

Quantum Physics · Physics 2007-05-23 Michal Horodecki , Jonathan Oppenheim , Andreas Winter

We report the experimental measurement of bipartite quantum correlations of an unknown two-qubit state. Using a liquid state Nuclear Magnetic Resonance (NMR) setup and employing geometric discord, we evaluate the quantum correlations of a…

The problem of detecting non-classical correlations of states of many qudits is incomparably more involved than in a case of qubits. The reason is that for qubits we have a convenient description of the system by the means of the…

Quantum Physics · Physics 2016-10-27 Krzysztof Rosołek , Marcin Wieśniak , Lukas Knips

We analyze the trade-off between the amounts of information obtainable on complementary properties of a qubit state by simultaneous measurements. We consider a "state discrimination" scenario wherein the same measurements are repeated, but…

Quantum Physics · Physics 2009-03-26 Noam Erez , Daniel Jacobs , Gershon Kurizki

Quantum Fisher information matrix (QFIM) is a core concept in theoretical quantum metrology due to the significant importance of quantum Cram\'{e}r-Rao bound in quantum parameter estimation. However, studies in recent years have revealed…

Quantum Physics · Physics 2020-03-27 Jing Liu , Haidong Yuan , Xiao-Ming Lu , Xiaoguang Wang