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Charge detection enables free-electron quantum computation

C. W. J. Beenakker·D. P. DiVincenzo·C. Emary·M. Kindermann
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Abstract

It is known that a quantum computer operating on electron-spin qubits with single-electron Hamiltonians and assisted by single-spin measurements can be simulated efficiently on a classical computer. We show that the exponential speed-up of quantum algorithms is restored if single-charge measurements are added. These enable the construction of a CNOT (controlled NOT) gate for free fermions, using only beam splitters and spin rotations. The gate is nearly deterministic if the charge detector counts the number of electrons in a mode, and fully deterministic if it only measures the parity of that number.

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C. W. J. Beenakker, D. P. DiVincenzo, C. Emary, M. Kindermann. 2004-01-12. Charge detection enables free-electron quantum computation. https://doi.org/10.1103/physrevlett.93.020501

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