Entanglement of Formation of an Arbitrary State of Two Qubits

  title={Entanglement of Formation of an Arbitrary State of Two Qubits},
  author={William K. Wootters},
  journal={Physical Review Letters},
  • W. Wootters
  • Published 12 September 1997
  • Physics
  • Physical Review Letters
The entanglement of a pure state of a pair of quantum systems is defined as the entropy of either member of the pair. The entanglement of formation of a mixed state is defined as the minimum average entanglement of an ensemble of pure states that represents the given mixed state. An earlier paper [Phys. Rev. Lett. 78, 5022 (1997)] conjectured an explicit formula for the entanglement of formation of a pair of binary quantum objects (qubits) as a function of their density matrix, and proved the… 
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