Marcellus Central School District and Marcellus Substitute Teachers Association

In the matter of the fact-finding between the Marcellus Central School District, employer, and the Marcellus Substitute Teachers Association, union. PERB case no. M2010-302. Before: Ben W. Budelmann, fact finder

Canton, Village of and Canton Department of Public Works Unit, CSEA Local 1000, AFSCME, AFL-CIO

In the matter of the fact-finding between the Village of Canton, employer, and the Canton Department of Public Works Unit, CSEA Local 1000, AFSCME, AFL-CIO, union. PERB case no. M2009-266. Before: Ben W. Budelmann, fact finder

Postselection threshold against biased noise

The highest current estimates for the amount of noise a quantum computer can tolerate are based on fault-tolerance schemes relying heavily on postselecting on no detected errors. However, there has been no proof that these schemes give even a positive tolerable noise threshold. A technique to prove a positive threshold, for probabilistic noise models, is presented. The main idea is to maintain strong control over the distribution of errors in the quantum state at all times. This distribution has correlations which conceivably could grow out of control with postselection. But in fact, the error distribution can be written as a mixture of nearby distributions each satisfying strong independence properties, so there are no correlations for postselection to amplify.Comment: 13 pages, FOCS 2006; conference versio