English
Related papers

Related papers: Quantum Correlations in Mixed-State Metrology

200 papers

Noisy unsharp measurements incorporated in quantum information protocols may hinder performance, reducing the quantum advantage. However, we show that, unlike projective measurements which completely destroy quantum correlations between…

Quantum Physics · Physics 2025-07-01 Sudipta Mondal , Pritam Halder , Amit Kumar Pal , Aditi Sen De

In the realm of quantum information processing, the efficient characterization of entangled states poses an overwhelming challenge, rendering the traditional methods including quantum tomography unfeasible and impractical. To tackle this…

Quantum Physics · Physics 2025-12-09 Ye-Chao Liu , Jiangwei Shang

We present a theoretical study of the relationship between entanglement and entropy in multi-qubit quantum optical systems. Specifically we investigate quantitative relations between the concurrence and linear entropy for a two-qubit mixed…

Quantum Physics · Physics 2009-11-10 Alexandra Olaya-Castro , Neil F. Johnson , Luis Quiroga

We investigate a family of qubit-oscillator states as resources for hybrid quantum communication. They result from a mechanism of qubit-controlled displacement on the oscillator. For large displacements, we obtain analytical formulas for…

Quantum Physics · Physics 2012-12-06 Tommaso Tufarelli , Davide Girolami , Ruggero Vasile , Sougato Bose , Gerardo Adesso

This article presents a comprehensive study of the impact of decoherence on the average correlation for pure quantum states. We explore two primary mechanisms of decoherence: phase damping and amplitude damping, each having distinct effects…

Quantum Physics · Physics 2024-03-19 A. M. Silva

Quantum metrology harnesses quantum entanglement to improve measurement precision beyond standard quantum limit. Although nonlinear interaction is essential for generating entanglement, during signal accumulation, it becomes detrimental and…

Quantum Physics · Physics 2026-02-06 Jihao Ma , Jiahao Huang , Chaohong Lee

When subject to a non-local unitary evolution, qubits in a quantum circuit become increasingly entangled. Conversely, measurements applied to individual qubits lead to their disentanglement from the collective system. The extent of…

Quantum Physics · Physics 2025-01-22 Sourav Manna , Vaibhav Madhok , Arul Lakshminarayan

Entanglement lies at the core of quantum algorithms designed to solve problems that are intractable by classical approaches. One such algorithm, quantum annealing (QA), provides a promising path to a practical quantum processor. We have…

Quantum correlation, such as entanglement and squeezing have shown to improve phase estimation in interferometric setups on one side, and non-interferometric imaging scheme of amplitude object on the other. In the last case, quantum…

Modular quantum computing provides a scalable approach to overcome the limitations of monolithic quantum architectures by interconnecting multiple Quantum Processing Units (QPUs) through a quantum network. In this work, we explore and…

Quantum Physics · Physics 2025-04-30 Shahrooz Pouryousef , Reza Nejabati , Don Towsley , Ramana Kompella , Eneet Kaur

Determination of the quantum nature of correlations between two spatially separated systems plays a crucial role in quantum information science. Of particular interest is the questions of if and how these correlations enable quantum…

Quantum Physics · Physics 2017-09-27 Farid Shahandeh , Austin P. Lund , Timothy C. Ralph

An accurate description of strong correlation is quintessential for the exploration of emerging chemical phenomena. While near-term variational quantum algorithms provide a theoretically scalable framework for quantum chemical problems, the…

Quantum Physics · Physics 2025-10-20 Arpan Choudhury , Sonaldeep Halder , Rahul Maitra , Debashree Ghosh

This work presents a theoretical framework for enhancing quantum correlations in a hybrid double-cavity optomechanical system that hosts an atomic ensemble. We investigate the role of the coupling phase $\phi$ between cavity 1 and the…

Quantum chaos is the study of quantum systems whose classical description is chaotic. How does chaos manifest itself in the quantum world? In this spirit, we study the dynamical generation of entanglement as a signature of chaos in a system…

Quantum Physics · Physics 2012-12-20 Vaibhav Madhok

The characterization of quantum correlations is crucial to the development of new quantum technologies and to understand how dramatically quantum theory departs from classical physics. Here we systematically study single- and multiparticle…

Quantum Physics · Physics 2020-06-05 Rejane Alves de Brito , Bertúlio de Lima Bernardo

Quantum discord is an optimal resource for the quantification of classical and non-classical correlations as compared to other related measures. Geometric measure of quantum discord is another measure of quantum correlations. Recently, the…

Quantum Physics · Physics 2013-08-06 M. Ramzan

Entanglement-enhanced quantum metrology explores the utilization of quantum entanglement to enhance measurement precision. When particles in a probe are prepared into a quantum entangled state, they collectively accumulate information about…

Quantum Physics · Physics 2024-08-20 Jiahao Huang , Min Zhuang , Chaohong Lee

The "Power of One Qubit" refers to a computational model that has access to only one pure bit of quantum information, along with n qubits in the totally mixed state. This model, though not as powerful as a pure-state quantum computer, is…

Quantum Physics · Physics 2009-11-11 Animesh Datta , Steven T. Flammia , Carlton M. Caves

Quantum discord, a measure of genuinely quantum correlations, is generalized to continuous variable systems. For all two-mode Gaussian states, we calculate analytically the quantum discord and a related measure of classical correlations,…

Quantum Physics · Physics 2015-03-13 Gerardo Adesso , Animesh Datta

It is found that the measurement disturbance relation (MDR) determines the strength of quantum correlation and hence is one of the essential facets of the nature of quantum nonlocality. In reverse, the exact form of MDR may be ascertained…

Quantum Physics · Physics 2015-06-22 Jun-Li Li , Kun Du , Cong-Feng Qiao