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arxiv: quant-ph/9709029 · v2 · submitted 1997-09-12 · 🪐 quant-ph

Entanglement of Formation of an Arbitrary State of Two Qubits

classification 🪐 quant-ph
keywords entanglementstateformationmixedpairstatesarbitrarydefined
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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 formula to be true for a special class of mixed states. The present paper extends the proof to arbitrary states of this system and shows how to construct entanglement-minimizing pure-state decompositions.

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