Cited by 2,823Quantum Information and CryptographyQuantum Mechanics and ApplicationsQuantum many-body systems

Entanglement of a pair of quantum bits

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Hill, Scott, Wootters, William K.·1997·Physical Review Letters

Abstract

The ``entanglement of formation'' of a mixed state \ensuremath{\rho} of a bipartite quantum system can be defined as the minimum number of singlets needed to create an ensemble of pure states that represents \ensuremath{\rho}. We find an exact formula for the entanglement of formation for all mixed states of two qubits having no more than two nonzero eigenvalues, and we report evidence suggesting that the formula is valid for all states of this system.

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Crossref · 10.1103/physrevlett.78.5022

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  • The matrix τ defined here coincides with that introduced in Eq. (38) in the 2×2 case.

    “The relation between the present and the original approach to concurrence [27,57] becomes apparent with the observation that the matrix τ defined here coincides with that introduced in Eq. (38)”

    From Measures and dynamics of entangled states (2005) · cites this paper as [57]

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Research works printed but not linked: 1

  1. [11][11] D. Bures, Trans. Am. Math. Soc. 135 , 199 (1969); A. Uhlmann, Rep. Math. Phys. 9 , 273 (1976); R. Jozsa, J. Mod. Optics 41 , 2315 (1994). -

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Authors
Hill, S., & Wootters, W. K.
Affiliations
Williams College (US)
Venue
Physical Review Letters
Published
1997-06-30
Volume
78
Issue
26
Pages
5022-5025
ISSN
  • 0031-9007 (ISSN-L)
  • 1079-7114
OpenAlex
W2073781628
Cited by
2,823
References
18
Citations by year
2026: 102 · 2025: 141 · 2024: 127 · 2023: 165 · 2022: 126 · 2021: 132 · 2020: 92 · 2019: 108 · 2018: 92 · 2017: 117 · 2016: 134 · 2015: 110 · 2014: 116 · 2013: 93 · 2012: 103
FWCI
17.04
Type
journal article
Language
en
Open access
Locations
  • Physical Review Letters (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • CERN Document Server (European Organization for Nuclear Research) (submittedVersion)
  • arXiv (Cornell University)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Quantum Information and Cryptography
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Mechanics and Applications
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum many-body systems
Keywords
entanglement of formation, two-qubit systems, mixed states, singlets, bipartite quantum systems, exact formulas, quantum entanglement

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