Maintaining coherence in quantum computers.

  title={Maintaining coherence in quantum computers.},
  journal={Physical review. A, Atomic, molecular, and optical physics},
  volume={51 2},
  • Unruh
  • Published 9 June 1994
  • Physics
  • Physical review. A, Atomic, molecular, and optical physics
The effects of the inevitable coupling to external degrees of freedom of a quantum computer are examined. It is found that for quantum calculations (in which the maintenance of coherence over a large number of states is important), not only must the coupling be small, but the time taken in the quantum calculation must be less than the thermal time scale \ensuremath{\Elzxh}/${\mathit{k}}_{\mathit{B}}$T. For longer times the condition on the strength of the coupling to the external world becomes… 

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ShorA l gori thm sforQ uantum C om putati on:D i screte l og and Factori ng AT & T Bel lLabs prepri nt M ay

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