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Programmable quantum gate arrays

M. A. Nielsen·Isaac L. Chuang
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Abstract

We show how to construct quantum gate arrays that can be programmed to perform different unitary operations on a data register, depending on the input to some program register. It is shown that a universal quantum gate array - a gate array which can be programmed to perform any unitary operation - exists only if one allows the gate array to operate in a probabilistic fashion. The universal quantum gate array we construct requires an exponentially smaller number of gates than a classical universal gate array.

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M. A. Nielsen, Isaac L. Chuang. 1997-03-18. Programmable quantum gate arrays. https://doi.org/10.1103/physrevlett.79.321

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