Volume 5, Issue 3, pages 98-109
Professor Anthony Sudbery was born in 1943 and educated at St Brendan’s College, Bristol and Cambridge University, where he obtained a PhD in theoretical elementary particle physics in 1969. He held a post-doctoral position in the University of Glasgow and since 1971 he has been a member of staff in the Department of Mathematics at the University of York (professor since 1995, emeritus since 2008). He is the author of Quantum Mechanics and the Particles of Nature: an outline for mathematicians (Cambridge University Press, 1986) and over 80 papers on pure mathematics, theoretical physics, philosophy, quantum information theory and the foundations of quantum mechanics.
This note is a critical examination of the argument of Frauchiger and Renner, in which they claim to show that three reasonable assumptions about the use of quantum mechanics jointly lead to a contradiction. It is shown that further assumptions are needed to establish the contradiction, and that each of these assumptions is invalid in some version of quantum mechanics.