# Maintaining coherence in quantum computers.

@article{Unruh1995MaintainingCI, title={Maintaining coherence in quantum computers.}, author={Unruh}, journal={Physical review. A, Atomic, molecular, and optical physics}, year={1995}, volume={51 2}, pages={ 992-997 } }

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… Expand

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