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Rapidly growing capabilities of quantum simulators to probe quantum many-body phenomena require new methods to characterize increasingly complex states. We present a protocol that constrains quantum states by experimentally measured…

Quantum Physics · Physics 2025-09-22 Henry Froland , Torsten V. Zache , Robert Ott , Niklas Mueller

There is a commonly recognized paradigm in which a multipartite quantum system described by a density matrix having no product eigenbasis is considered to possess nonclassical correlation. Supporting this paradigm, we define two entropic…

Quantum Physics · Physics 2008-05-02 Akira SaiToh , Robabeh Rahimi , Mikio Nakahara

It is shown how to obtain state vectors associated with measurements on the separated subystems of an entangled state, revealing how a single wavefunction encodes a set of statistical measurement outcomes. The result explains why…

Quantum Physics · Physics 2026-05-21 Grgeory D. Scholes

Quantum state tomography is a technique in quantum information science used to reconstruct the density matrix of an unknown quantum state, providing complete information about the quantum state. It is of significant importance in fields…

Quantum Physics · Physics 2025-07-23 Wenlong Zhao , Da Zhang , Huili Zhang , Haifeng Yu , Zhang-qi Yin

Entanglement plays a central role in quantum information processing, indicating the non-local correlation of quantum matters. However, few effective ways are known to detect the amount of entanglement of an unknown quantum state. In this…

Quantum Physics · Physics 2020-11-26 You Zhou , Pei Zeng , Zhenhuan Liu

Dissimilar notions of quantum correlations have been established, each being motivated through particular applications in quantum information science and each competing for being recognized as the most relevant measure of quantumness. In…

Quantum Physics · Physics 2021-05-05 S. Köhnke , E. Agudelo , M. Schünemann , O. Schlettwein , W. Vogel , J. Sperling , B. Hage

It is shown that a choice of degrees of freedom of a bipartite continuous variable system determines amount of non-classical correlations (quantified by discord) in the system's state. Non-classical correlations (that include entanglement…

Quantum Physics · Physics 2013-04-01 M. Dugic , M. Arsenijevic , J. Jeknic-Dugic

Quantum correlations between parts of a composite system most clearly reveal themselves through entanglement. Designing, maintaining, and controlling entangled systems is very demanding, which raises the stakes for understanding the…

Quantum Physics · Physics 2019-09-04 Matthew A. Hunt , Igor V. Lerner , Igor V. Yurkevich , Yuval Gefen

To our knowledge, all known bipartite entanglement measures are symmetric under exchange of subsystems. We ask if an entanglement measure that is not symmetric can exist. A related question is if there is a state that cannot be swapped by…

Quantum Physics · Physics 2007-05-23 Karol Horodecki , Michal Horodecki , Pawel Horodecki

We present a quantum Monte Carlo-based approach to detect and compute the most dominant correlations for many-body systems without prior knowledge. It is based on the measurement and analysis of the correlation density matrix between two…

Strongly Correlated Electrons · Physics 2026-05-25 Aditya Chincholi , Sylvain Capponi , Fabien Alet

Non-classical correlations denote the ways in which quantum systems can be correlated beyond what is possible in classical physics. They include but are not limited to entanglement: non-entangled states can also exhibit forms of…

Quantum Physics · Physics 2016-09-09 Pieter Bogaert , Davide Girolami

A generalized uncertainty relation for an entangled pair of particles is obtained if we impose a symmetrization rule for all operators that we should use when doing any calculation using the entangled wave function of the pair. This new…

Quantum Physics · Physics 2009-09-25 G. Rigolin

We show how many-body ground state entanglement information may be extracted from sub-system energy measurements at zero temperature. A precise relation between entanglement and energy fluctuations is demonstrated in the weak coupling…

Quantum Physics · Physics 2009-11-11 Andrew N. Jordan , Markus Buttiker

The fact that quantum mechanics predicts stronger correlations than classical physics is an essential cornerstone of quantum information processing. Indeed, these quantum correlations are a valuable resource for various tasks, such as…

The simplicity of a question such as wondering if correlations characterize or not a certain system collides with the experimental difficulty of accessing such information. Here we present a low demanding experimental approach which refers…

We study emerging notions of quantum correlations in compound systems. Based on different definitions of quantumness in individual subsystems, we investigate how they extend to the joint description of a composite system. Especially, we…

Quantum Physics · Physics 2017-06-12 J. Sperling , E. Agudelo , I. A. Walmsley , W. Vogel

Multipartite quantum states constitute the key resource for quantum computation. The understanding of their internal structure is thus of great importance in the field of quantum information. This paper aims at examining the structure of…

Quantum Physics · Physics 2023-08-09 Arthur Vesperini

The correlation distance quantifies the statistical independence of two classical or quantum systems, via the distance from their joint state to the product of the marginal states. Tight lower bounds are given for the mutual information…

Quantum Physics · Physics 2013-09-23 Michael J. W. Hall

Quantum systems unfold diversified correlations which have no classical counterparts. These quantum correlations have various different facets. Quantum entanglement, as the most well known measure of quantum correlations, plays essential…

The recent development of single-atom-resolved probes has made full counting statistics measurements accessible in quantum gas experiments. This capability provides access to high-order moments of physical observables, from which cumulants,…