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We reexamine quantum correlation from the fundamental perspective of its consanguineous quantum property, the coherence. We emphasize the importance of specifying the tensor product structure of the total state space before discussing…

Quantum Physics · Physics 2011-04-01 Pei Pei , Wei Wang , Chong Li , He-Shan Song

Quantum non-Gaussianity is a key resource for quantum advantage in continuous-variable systems. We introduce a general framework to quantify non-Gaussianity based on correlation generation: two copies of a state become correlated at a…

Quantum Physics · Physics 2025-08-28 Oliver Hahn , Ryuji Takagi

Given a quantum system on many qubits split into a few different parties, how many total correlations are there between these parties? Such a quantity, aimed to measure the deviation of the global quantum state from an uncorrelated state…

Quantum Physics · Physics 2022-02-15 Zhenhuan Liu , Pei Zeng , You Zhou , Mile Gu

We present a general method to characterize the quantum correlations obtained after local measurements on multipartite systems. Sufficient conditions for a quantum system to be fully-nonlocal according to a given partition, as well as being…

Quantum Physics · Physics 2015-05-14 Mafalda L. Almeida , Daniel Cavalcanti , Valerio Scarani , Antonio Acin

In this work, we deal with the relaxation of two central assumptions in standard locally realistic hidden variable (LRHV) inequalities: free will in choosing measurement settings, and the presence of perfect detectors at the measurement…

Quantum Physics · Physics 2023-02-07 Abhishek Sadhu , Siddhartha Das

We experimentally prepare a new type of continuous variable genuine four-partite entangled states, the quantum correlation property of which is different from that of the four-mode GHZ and cluster states, and which has not any qubit…

Quantum Physics · Physics 2009-11-13 Aihong Tan , Yu Wang , Xiaoli Jin , Xiaolong Su , Xiaojun Jia , Jing Zhang , Changde Xie , Kunchi Peng

While commonly used entanglement criteria for continuous variable systems are based on quadrature measurements, here we study entanglement detection from measurements of the Wigner function. These are routinely performed in platforms such…

Quantum Physics · Physics 2026-03-25 Shuheng Liu , Jiajie Guo , Qiongyi He , Matteo Fadel

Quantumness and separability criteria for continuous variable systems are discussed for the case of a noncommutative (NC) phase-space. In particular, the quantum nature and the entanglement configuration of NC two-mode Gaussian states are…

Quantum Physics · Physics 2015-10-13 Alex E. Bernardini , Catarina Bastos , Orfeu Bertolami , Nuno C. Dias , João N. Prata

Continuous-variable quantum states are of particular importance in various quantum information processing tasks including quantum communication and quantum sensing. However, a bottleneck has emerged with the fast increasing in size of the…

Quantum Physics · Physics 2021-10-13 Ye-Chao Liu , Jiangwei Shang , Xiangdong Zhang

Conventionally the total correlations within a quantum system are quantified through distance-based expressions such as the relative entropy or the square-norm. Those expressions imply that a quantum state can contain both classical and…

Quantum Physics · Physics 2025-03-13 Spyros Tserkis , Syed M. Assad , Ping Koy Lam , Prineha Narang

This article provides an exact formula for the signal n-point correlation functions of detectors continuously measuring an arbitrary quantum system, in the presence of detection imperfections. The derivation uses only continuous stochastic…

Quantum Physics · Physics 2018-08-08 Antoine Tilloy

Quantum correlations are contextual yet, in general, nothing prevents the existence of even more contextual correlations. We identify and test a noncontextuality inequality in which the quantum violation cannot be improved by any…

Understanding the role of correlations in quantum systems is both a fundamental challenge as well as of high practical relevance for the control of multi-particle quantum systems. Whereas a lot of research has been devoted to study the…

Quantum Physics · Physics 2015-07-16 Ángel Rivas , Markus Müller

We present strictly efficient schemes for scalable measurement-based quantum computing using continuous-variable systems: These schemes are based on suitable non-Gaussian resource states, ones that can be prepared using interactions of…

Quantum Physics · Physics 2013-05-30 Matthias Ohliger , Jens Eisert

Traditionally, quantum state correlation can be obtained with calculations on a state density matrix already known. Here, we propose a model with which correlations of unknown quantum states can be obtained. There are no needs of classical…

Quantum Physics · Physics 2018-06-18 Hui Li , Yan-Song Li , Chao Zheng , Xian Lu

We propose in this work a practical approach to address the longstanding and challenging problem of quantum separability, leveraging the correlation matrices of generic observables. General separability conditions are obtained by dint of…

Quantum Physics · Physics 2025-05-07 Ma-Cheng Yang , Cong-Feng Qiao

The verification and quantification of experimentally created entanglement by simple measurements, especially between distant particles, is an important basic task in quantum processing. When composite systems are subjected to local…

Quantum Physics · Physics 2009-11-13 K. M. R. Audenaert , M. B. Plenio

Our study employs a connected correlation matrix to quantify Quantum Entanglement. The matrix encompasses all necessary measures for assessing the degree of entanglement between particles. We begin with a three-qubit state and involve…

Quantum Physics · Physics 2023-12-06 Xingyu Guo , Chen-Te Ma

Non-locality is a fundamental trait of quantum many-body systems, both at the level of pure states, as well as at the level of mixed states. Due to non-locality, mixed states of any two subsystems are correlated in a stronger way than what…

Statistical Mechanics · Physics 2016-09-28 Daniele Malpetti , Tommaso Roscilde

The present article proposes a measure of correlation for multiqubit mixed states. The measure is defined recursively, accumulating the correlation of the subspaces, making it simple to calculate without using of regression. Unlike usual…