arXiv subjects
Publications and source records attributed to N. David Mermin.
I describe aspects of my life in physics: the name I publish under, great physicists I have known, how I got into quantum foundations, what role I've played in it. My form is autobiographical, but my personal experience may illustrate what it was like being a physicist over the past 60 years. I offer some offbeat ways of thinking about some orthodox physics.
The idea that wave-function collapse is a physical process stems from a misunderstanding of probability and the role it plays in quantum mechanics.
We review the famous no-hidden-variables theorem in John von Neumann's 1932 book on the mathematical foundations of quantum mechanics. We describe the notorious gap in von Neumann's argument, pointed out by Grete Hermann in 1935 and, more famously, by John Bell in 1966. We disagree with recent papers claiming that Hermann and Bell failed to understand what von Neumann was actually doing.
We still lack any consensus about what one is actually talking about as one uses quantum mechanics. There is a gap between the abstract terms in which the theory is couched and the phenomena the theory enables each of us to account for so well. Because it has no practical consequences for how we each use quantum mechanics to deal with physical problems, this cognitive dissonance has managed to coexist with the quantum theory from the very beginning. The absence of conceptual clarity for almost a century suggests that the problem might lie in some implicit misconceptions about the nature of scientific explanation that are deeply held by virtually all physicists, but are rarely explicitly acknowledged. I describe here such unvoiced but widely shared assumptions. Rejecting them clarifies and unifies a range of obscure remarks about quantum mechanics made almost from the beginning by some of the giants of physics, many of whom are held to be in deep disagreement. This new view of physics requires physicists to think about science in an unfamiliar way. My primary purpose is to explain the new perspective and urge that it be taken seriously. My secondary aims are to explain why this perspective differs significantly from what Bohr, Heisenberg, and Pauli had been saying from the very beginning, and why it is not solipsism, as some have maintained. To emphasize that this is a general view of science, and not just of quantum mechanics, I apply it to a long-standing puzzle in classical physics: the apparent inability of physics to give any meaning to "Now" --- the present moment.
Although skeptical of the prohibitive power of no-hidden-variables theorems, John Bell was himself responsible for the two most important ones. I describe some recent versions of the lesser known of the two (familar to experts as the "Kochen-Specker theorem") which have transparently simple proofs. One of the new versions can be converted without additional analysis into a powerful form of the very much better known "Bell's Theorem", thereby clarifying the conceptual link between these two results of Bell.
Speech on the occasion of accepting the Dagmar and Vaclav Havel Foundation VIZE 97 Prize for 2017. Delivered at Prague Crossroads, October 5, 2017
This is a reply to Michael Nauenberg's arXiv:1502.00123, to be published in the American Journal of Physics, in which he comments critically on our paper "An introduction to QBism with an application to the locality of quantum mechanics", Am. J. Phys. 82, 749--754 (2014) and arXiv:1311.5253.
Christopher Fuchs and Rüdiger Schack have developed a way of understanding science, which, among other things, resolves many of the conceptual puzzles of quantum mechanics that have vexed people for the past nine decades. They call it QBism. I speculate on how John Bell might have reacted to QBism, and I explain the many ways in which QBism differs importantly from the orthodox ways of thinking about quantum mechanics associated with the term "Copenhagen interpretation."
The QBist view of science, first put forth to dispel the fog from quantum foundations, also clears up a longstanding puzzle in classical physics.
We give an introduction to the QBist interpretation of quantum mechanics. We note that it removes the paradoxes, conundra, and pseudo-problems that have plagued quantum foundations for the past nine decades. As an example, we show in detail how it eliminates quantum "nonlocality".
These are my published answers to the seventeen questions posed by Max Schlosshauer in his 2011 book "Elegance and Enigma: the Quantum Interviews". I have inserted thirty footnotes into those answers, commenting on them from the perspective of subsequent insights I acquired during six weeks in March and April of 2012 with Chris Fuchs and Ruediger Schack at the Stellenbosch Institute for Advanced Study. Aside from the footnotes and a few introductory paragraphs, the text is identical to my contributions to the Schlosshauer volume.
A physicists' explanation of why thou shalt not clone one bit gives a stronger version of Conway and Kochen's theorem.
I comment on GianCarlo Ghirardi's criticism of my claim that quantum computation has no measurement problem.
The role of measurement in quantum computation is examined in the light of John Bell's critique of the how the term ``measurement'' is used in quantum mechanics. I argue that within the field of quantum computer science the concept of measurement is precisely defined, unproblematic, amd forms the foundation of the entire subject.
Minkowski diagrams in 1+1 dimensional flat space-time are given a strictly geometric derivation, directly from two gedanken experiments incorporating the principle of the constancy of the velocity of light and the principle of (special) relativity. Rectangles of photon trajectories play a central role in determining the simultaneity convention and in establishing the invariance of the interval.
To celebrate the 60th birthday of Charles H.Bennett I (1) publicly announce my referee reports for the original dense coding and teleportation papers, (2) present a very economical solution to the Bernstein-Vazirani problem that does not even hint at interference between multiple universes, and (3) describe how I inadvertently reinvented the Copenhagen interpretation in the course of constructing a simple, straightforward, and transparent introduction to quantum mechanics for computer scientists.
This is based on the after-dinner talk given at the 70th Birthday Conference for Michael E. Fisher at Rutgers in December, 2001. It is longer than the talk, incorporating additional text from the after-dinner talk I gave at Fisher's 60th Birthday Conference at the National Academy in Washington D.C.in 1991.