Measurement efficiency and n-shot read out of spin qubits

2003/09/01 by Hans-Andreas Engel, Vitaly Golovach, Daniel Loss +4 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #quant-ph

paper · pdf · doi:10.1103/physrevlett.93.106804

published as Phys. Rev. Lett. 93, 106804 (2004) · 5 pages, 1 figure

arxiv created 2003/09/01 · arxiv updated 2009/12/01

Abstract

We consider electron spin qubits in quantum dots and define a measurement efficiency e to characterize reliable measurements via n-shot read outs. We propose various implementations based on a double dot and quantum point contact (QPC) and show that the associated efficiencies e vary between 50% and 100%, allowing single-shot read out in the latter case. We model the read out microscopically and derive its time dynamics in terms of a generalized master equation, calculate the QPC current and show that it allows spin read out under realistic conditions.

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