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Title: Universal construction of controlled-unitary gates using dynamical decoupling and the quantum Zeno effect

We present two new algorithms that universally construct a quantum circuit approximating a controlled-U(t) up to a global phase factor of U(t), denoted by Λ{sub θ}U(t), where U(t) = e{sup −iHt} is the unitary evolution operator of an unknown Hamiltonian H of the system, and is given as a black box with tunable parameter t. We show that it is possible to approximately construct Λ{sub θ}U(t) with arbitrarily high accuracy. This algorithm is based on the dynamical decoupling effect [1]. If another black box consisting of a time-inverted version of U(t), namely U(−t), is also available we can implement Λ{sub θ}U(t) exactly with arbitrarily high success probability. This algorithm is based on the quantum Zeno effect.
Authors:
 [1] ;  [2] ;  [3]
  1. Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-0033 (Japan)
  2. Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore (Singapore)
  3. Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-0033 Japan and Institute for Nano Quantum Information Electronics, University of Tokyo, Tokyo 153-8505 (Japan)
Publication Date:
OSTI Identifier:
22390682
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1633; Journal Issue: 1; Conference: 11. International Conference on Quantum Communication, Measurement and Computation, Vienna (Austria), 30 Jul - 3 Aug 2012; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; ALGORITHMS; APPROXIMATIONS; DECOUPLING; HAMILTONIANS; POWER FACTOR; PROBABILITY; QUANTUM MECHANICS; QUANTUM OPERATORS; UNITARITY