Comment on 'Noise and Disturbance in Quantum Measurements: An Information-Theoretic Approach'

摘要

In this comment on the work of F. Buscemi, M.J.W. Hall, M. Ozawa and M.M.Wilde [PRL 112, 050401, 2014, arXiv:1310.6603], we point out amisrepresentation of measures of error and disturbance introduced in our recentwork [PRL 111, 160405, 2013, arXiv:1306.1565] as being "purely formal, with nooperational counterparts". We also exhibit an tension in the authors' message,in that their main result is an error-disturbance relation forstate-independent measures, but its importance is declared to be limited todiscrete variables. In contrast, we point out the separate roles played by suchrelations for either state-dependent or state-independent measures of error anddisturbance.