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Lower bound for electron spin entanglement from beamsplitter current correlations

Guido Burkard·Daniel Loss
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Abstract

We determine a lower bound for the entanglement of pairs of electron spins injected into a mesoscopic conductor. The bound can be expressed in terms of experimentally accessible quantities, the zero-frequency current correlators (shot noise power or cross-correlators) after transmission through an electronic beam splitter. The effect of spin relaxation (T_1 processes) and decoherence (T_2 processes) during the ballistic coherent transmission of the carriers in the wires is taken into account within Bloch theory. The presence of a variable inhomogeneous magnetic field allows the determination of a useful lower bound for the entanglement of arbitrary entangled states. The decrease in entanglement due to thermally mixed states is studied. Both the entanglement of the output of a source (entangler) and the relaxation (T_1) and decoherence (T_2) times can be determined.

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Guido Burkard, Daniel Loss. 2003-03-11. Lower bound for electron spin entanglement from beamsplitter current correlations. https://doi.org/10.1103/physrevlett.91.087903

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