Foundations of Physics Letters

, Volume 14, Issue 3, pp 199–212 | Cite as

Entanglement of Formation of an Arbitrary State of Two Rebits

  • Carlton M. Caves
  • Christopher A. Fuchs
  • Pranaw Rungta


We consider entanglement for quantum states defined in vector spaces over the real numbers. Such real entanglement is different from entanglement in standard quantum mechanics over the complex numbers. The differences provide insight into the nature of entanglement in standard quantum theory. Wootters [Phys. Rev. Lett.80, 2245 (1998)] has given an explicit formula for the entanglement of formation of two qubits in terms of what he calls the concurrence of the joint density operator. We give a contrasting formula for the entanglement of formation of an arbitrary state of two “rebits,” a rebit being a system whose Hilbert space is a 2-dimensional real vector space.

quantum entanglement quantum information real quantum mechanics 


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Copyright information

© Plenum Publishing Corporation 2001

Authors and Affiliations

  • Carlton M. Caves
    • 1
  • Christopher A. Fuchs
    • 2
  • Pranaw Rungta
    • 3
  1. 1.Center for Advanced Studies, Department of Physics and AstronomyUniversity of New MexicoAlbuquerque
  2. 2.Los Alamos National Laboratory, MS-B285Los Alamos
  3. 3.Center for Advanced Studies, Department of Physics and AstronomyUniversity of New MexicoAlbuquerque

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