Equivalence between Two-Qubit Entanglement and Secure Key Distribution
- 13 October 2003
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 91 (16) , 167901
- https://doi.org/10.1103/physrevlett.91.167901
Abstract
We study the problem of secret key distillation from bipartite states in the scenario where Alice and Bob can perform measurements only at the single-copy level and classically process the obtained outcomes. Even with these limitations, secret bits can be asymptotically distilled by the honest parties from any two-qubit entangled state, under any individual attack. Our results point out a complete equivalence between two-qubit entanglement and secure key distribution: a key can be established through a one-qubit channel if and only if it allows one to distribute entanglement. These results can be generalized to a higher dimension for all those states that are one-copy distillable.Keywords
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