Category Archives: Quantum Mechanics

What’s the difference between Copenhagen and Everett?

I’ve just finished reading Sean Carroll’s forthcoming new book, will write something about it in the next few weeks. Reading the book and thinking about it did clarify various issues for me, and I thought it might be a good … Continue reading

Posted in Quantum Mechanics | 26 Comments

Not So Spooky Action at a Distance

I’ve recently read another new popular book about quantum mechanics, Quantum Strangeness by George Greenstein. Before getting to saying something about the book, I need to get something off my chest: what’s all this nonsense about Bell’s theorem and supposed … Continue reading

Posted in Book Reviews, Quantum Mechanics | 62 Comments

Is Quantum Mechanics a Probabilistic Theory?

There is a simple question about quantum theory that has been increasingly bothering me. I keep hoping that my reading about interpretational issues will turn up a discussion of this point, but that hasn’t happened. I’m hoping someone expert in … Continue reading

Posted in Quantum Mechanics | 74 Comments

What is Real?

There’s a new popular book out this week about the interpretation of quantum mechanics, Adam Becker’s What is Real?: The Unfinished Quest for the Meaning of Quantum Physics. Ever since my high school days, the topic of quantum mechanics and … Continue reading

Posted in Book Reviews, Quantum Mechanics | 74 Comments

Various Topics in Interpretation of Quantum Mechanics

A couple of recent discussions about quantum mechanics that may be of interest: There’s a recent paper out by Don Weingarten that looks looks like it might have a different take on the fundamental “many-worlds” problem of, as he writes: … Continue reading

Posted in Quantum Mechanics | 19 Comments

The Free Particle

Following on my notes about Euler’s formula, I’ve finally finished some work on another piece of elementary exposition, a discussion of the free quantum particle, which can be found as chapters 10, 11 and 12 of the book I’m working … Continue reading

Posted in Quantum Mechanics | 19 Comments

This Week’s Hype

From commenter Hendrik, there’s the news that USC has put out a press release claiming that String Theory Could Be the Foundation of Quantum Mechanics. These claims are based on this paper, which argues that finding the Heisenberg commutation relations … Continue reading

Posted in Quantum Mechanics, This Week's Hype | 5 Comments

Use the Moment Map, not Noether’s Theorem

For a fourth provocative slogan about quantum mechanics I’ve chosen: Use the moment map, not Noether’s Theorem. Pretty much every physics textbook these days explains the way symmetry principles work as: Start with an action functional, invariant under a Lie … Continue reading

Posted in Favorite Old Posts, Quantum Mechanics | 25 Comments

Nature is Fundamentally Conformally Invariant

For a third slogan I’ve chosen: Nature is fundamentally conformally invariant. Note the weasel-word “fundamentally”. We know that nature is not conformally invariant, but the kind of thing I have in mind is pure QCD, where the underlying classical theory … Continue reading

Posted in Favorite Old Posts, Quantum Mechanics | 33 Comments

Grand Unification of Mathematics and Physics

For a second slogan about quantum mechanics I’ve chosen: Quantum mechanics is evidence of a grand unification of mathematics and physics. I’m not sure whether this slogan is likely to annoy physicists or mathematicians more, but in any case Edward … Continue reading

Posted in Favorite Old Posts, Quantum Mechanics, Uncategorized | 7 Comments