Archive for September 12, 2018

Making Better Sense of Quantum Mechanics

Posted in The Universe and Stuff with tags , , , on September 12, 2018 by telescoper

There is an interesting, pithy and polemical paper on the arXiv by David Mermin, with the abstract:

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.

The `new perspective’ Mermin espouses is a form of `QBism (i.e. `Quantum Bayesianism’)‘. You can download the full article for free here.

R.I.P. Fenella Fielding

Posted in Film with tags , on September 12, 2018 by telescoper

I was very sad last night to hear news of the death, at the age of 90, of the sublime Fenella Fielding. There was much more to Fenella Fielding than the Carry On films – she only appeared in two, but everyone will remember her as Valeria in the hilarious spoof horror movie Carry on Screaming with the classic gag “Do you mind if I smoke?”

R.I.P. Fenella Fielding (1927-2018).