Counterfactual computation revisited
Abstract
Mitchison and Jozsa recently suggested that the "chained-Zeno" counterfactual computation protocol recently proposed by Hosten et al. is counterfactual for only one output of the computer. This claim was based on the existing abstract algebraic definition of counterfactual computation, and indeed according to this definition, their argument is correct. However, a more general definition (physically adequate) for counterfactual computation is implicitly assumed by Hosten et. al. Here we explain in detail why the protocol is counterfactual and how the "history tracking" method of the existing description inadequately represents the physics underlying the protocol. Consequently, we propose a modified definition of counterfactual computation. Finally, we comment on one of the most interesting aspects of the error-correcting protocol.
Cite
@article{arxiv.quant-ph/0607101,
title = {Counterfactual computation revisited},
author = {Onur Hosten and Matthew T. Rakher and Julio T. Barreiro and Nicholas A. Peters and Paul Kwiat},
journal= {arXiv preprint arXiv:quant-ph/0607101},
year = {2007}
}
Comments
12 Pages, 8 Figures, 4 Tables in total. Mitchison and Jozsa responded to our article and the current form includes a reply (5 pages) to them. The text is unchanged otherwise. We provide two abstracts: one for the original aricle, one for the updates