Quantum Discord and Nonclassical Correlations Beyond Entanglement

Adesso, Gerardo; Cianciaruso, Marco; Bromley, Thomas R.

doi:10.1002/9783527805785.ch9

Cited by 3 publications

(5 citation statements)

References 48 publications

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“…( 15)). 67 Due to its particular significance for quantum information tasks and for the sake of simplicity we focus in our work on entanglement, however, and refer to it occasionally as quantum correlation.…”

Section: A Total Correlation Entanglement and Classical Correlationmentioning

confidence: 99%

“…In general, entanglement and classical correlation do not sum to the total correlation. This is because mixed quantum states typically contain quantum correlations beyond entanglement as it is concisely described by the concept of quantum discord . Moreover, a known exact relation including quantum discord refers to an alternative definition of classical correlation that is more technical than our simple geometric one (see eq ).…”

Section: Quantum Information Theoretical Conceptsmentioning

confidence: 99%

“…Moreover, a known exact relation including quantum discord refers to an alternative definition of classical correlation that is more technical than our simple geometric one (see eq ). Due to its particular significance for quantum information tasks and for the sake of simplicity, we focus in our work on entanglement, however, and refer to it occasionally as quantum correlation.…”

Section: Quantum Information Theoretical Conceptsmentioning

confidence: 99%

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Concept of Orbital Entanglement and Correlation in Quantum Chemistry

Ding

Mardazad

Das

et al. 2020

J. Chem. Theory Comput.

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A recent development in quantum chemistry has established the quantum mutual information between orbitals as a major descriptor of electronic structure. This has already facilitated remarkable improvements in numerical methods and may lead to a more comprehensive foundation for chemical bonding theory. Building on this promising development, our work provides a refined discussion of quantum information theoretical concepts by introducing the physical correlation and its separation into classical and quantum parts as distinctive quantifiers of electronic structure. In particular, we succeed in quantifying the entanglement. Intriguingly, our results for different molecules reveal that the total correlation between orbitals is mainly classical, raising questions about the general significance of entanglement in chemical bonding. Our work also shows that implementing the fundamental particle number superselection rule, so far not accounted for in quantum chemistry, removes a major part of correlation and entanglement seen previously. In that respect, realizing quantum information processing tasks with molecular systems might be more challenging than anticipated.

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Section: A Total Correlation Entanglement and Classical Correlationmentioning

confidence: 99%

Section: Quantum Information Theoretical Conceptsmentioning

confidence: 99%

Section: Quantum Information Theoretical Conceptsmentioning

confidence: 99%

See 1 more Smart Citation

Concept of Orbital Entanglement and Correlation in Quantum Chemistry

Ding

Mardazad

Das

et al. 2020

J. Chem. Theory Comput.

View full text Add to dashboard Cite

show abstract

“…The classical correlation can be visualised by the geometrical distance between σ * and the closest uncorrelated state. In general, the amount of entanglement and classical correlation does not sum up to the total correlation (I = E + C) as mixed quantum states give rise to correlation described by the quantum discord [32].…”

Section: Definition 22 (Separable and Entangled States)mentioning

confidence: 99%

Mode entanglement in fermionic and bosonic Harmonium

Ernst,

Tennie

2024

New J. Phys.

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Mode entanglement in many-body quantum systems is an active area of research. It providescrucial insight into the suitability of many-body systems for quantum information processing tasks.Local super-selection rules must be taken into account when assessing the amount of physicallyaccessible entanglement. This requires amending well-established entanglement measures by in-corporating local parity and local particle number constraints. In this paper, we report on modeentanglement present in the analytically solvable system of N -Harmonium. To the knowledge of theauthors, this is the first analytic study of the physically accessible mode and mode-mode entangle-ment of an interacting many-body system in a continuous state space. We find that super-selectionrules dramatically reduce the amount of physically accessible entanglement, which vanishes entirelyin some cases. Our results strongly suggest the need to re-evaluate intra and inter-mode entangle-ment in other fermionic and bosonic systems.

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“…It is then clear that (ii) implies that we can treat x 0 , x 1 and x + , x − as operational generalization of two different orthonormal sets in quantum theory, while (i) implies that the linear hulls of these sets overlap. In this sense, one can also interpret the result of Theorem 3 as stating that any non-classical state space exhibits an operational form of quantum discord [37,38].…”

Section: Entangleability Bb84mentioning

confidence: 99%

Entanglement and superposition are equivalent concepts in any physical theory

Aubrun,

Lami,

Palazuelos

et al. 2021

Preprint

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Quantum Discord and Nonclassical Correlations Beyond Entanglement

Cited by 3 publications

References 48 publications

Concept of Orbital Entanglement and Correlation in Quantum Chemistry

Concept of Orbital Entanglement and Correlation in Quantum Chemistry

Mode entanglement in fermionic and bosonic Harmonium

Entanglement and superposition are equivalent concepts in any physical theory

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