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Physica Scripta

Quantum Interferometers as Quantum Computers

ARTUR K. EKERT

Published Jan 1, 1998• 15 citations
Publisher

Abstract

Quantum computers which use quantum interference of different computational paths to enhance correct outcomes and suppress erroneous outcomes of computations can be viewed as multiparticle interferometers. I discuss this approach to quantum computation and argue that it provides additional insights into the nature of quantum algorithms.
DOI
10.1238/physica.topical.076a00218

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Quantum computers use the quantum interference of different computational paths to enhance correct outcomes and suppress erroneous outcomes of computations. A common pattern underpinning quantum algorithms can be identified when quantum computation is viewed as multiparticle interference. We use this approach to review (and improve) some of the existing quantum algorithms and to show how they are related to different instances of quantum phase estimation. We provide an explicit algorithm for generating any prescribed interference pattern with an arbitrary precision.
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Quantum computers use the quantum interference of different computational paths to enhance correct outcomes and suppress erroneous outcomes of computations. In effect, they follow the same logical paradigm as (multi-particle) interferometers. We show how most known quantum algorithms, including quantum algorithms for factorising and counting, may be cast in this manner. Quantum searching is described as inducing a desired relative phase between two eigenvectors to yield constructive interference on the sought elements and destructive interference on the remaining terms.
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