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arXiv:quant-ph/0006034 · Physical Review Letters

Entanglement Capabilities of Nonlocal Hamiltonians

Wolfgang Dür, Guifré Vidal, J. I. Cirac, Noah Linden, Sandu Popescu

Published Sep 10, 2001• 172 citations
arXivHTMLPDF

Abstract

We quantify the capability of creating entanglement for a general physical interaction acting on two qubits. We give a procedure for optimizing the generation of entanglement. We also show that a Hamiltonian can create more entanglement if one uses auxiliary systems.
DOI
10.1103/physrevlett.87.137901

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The evolution of two qubits coupled by a general nonlocal interaction is studied in two distinct regimes. In the first regime the purity of the individual qubits is interchanged through the entanglement shared by the two. We illustrate how this can be a mechanism for decoherence. In the second regime, the interaction entangles two initially pure qubits. The dynamical maps for the reduced unitary evolution of both initially simply separable and not-simply-separable states are found. We outline a protocol for optimizing the entanglement generation subject to constraints.