title: Impossibility of the counterfactual computation for all possible outcomes.
abstract: A recent proposal for counterfactual computation [O. Hosten et al. Nature (London) 439, 949 (2006) is analyzed. It is argued that the method does not provide counterfactual computation for all possible outcomes. The explanation involves a novel paradoxical feature of pre- and postselected quantum particles: The particle can reach a certain location without being on the path that leads to this location.
authors.affiliation: School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: L
authors.initials: L
authors.lastname: Vaidman