English

The limits of counterfactual computation

Quantum Physics 2007-05-23 v3

Abstract

We show that the protocol recently proposed by Hosten et al. does not allow all possible results of a computation to be obtained counterfactually, as was claimed. It only gives a counterfactual outcome for one of the computer outputs. However, we confirm the observation that the protocol gives some protection against decoherence. In some situations, though, it may be more effective simply to run the computer several times.

Cite

@article{arxiv.quant-ph/0606092,
  title  = {The limits of counterfactual computation},
  author = {Graeme Mitchison and Richard Jozsa},
  journal= {arXiv preprint arXiv:quant-ph/0606092},
  year   = {2007}
}

Comments

Hosten et al. have responded to the second version of this paper, and the present version includes our reply to them. The text is otherwise unchanged

R2 v1 2026-07-22T19:55:27.838Z