No-go theorem for iterations of unknown quantum gates

Soleimanifar, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1103/PhysRevA.93.012344
  3. Publisher: American Physical Society
  4. Abstract:
  5. We propose a no-go theorem by proving the impossibility of constructing a deterministic quantum circuit that iterates a unitary oracle by calling it only once. Different schemes are provided to bypass this result and to approximately realize the iteration. The optimal scheme is also studied. An interesting observation is that for a large number of iterations, a trivial strategy like using the identity channel has the optimal performance, and preprocessing, postprocessing, or using resources like entanglement does not help at all. Intriguingly, the number of iterations, when being large enough, does not affect the performance of the proposed schemes
  6. Keywords:
  7. Quantum electronics ; Reconfigurable hardware ; No-go theorem ; Number of iterations ; Optimal performance ; Optimal scheme ; Quantum circuit ; Quantum gates ; Molecular physics
  8. Source: Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 93, Issue 1 , 2016 ; 10502947 (ISSN)
  9. URL: https://journals-aps-org/pra/abstract/10.1103/PhysRevA.93.012344