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# Category Archives: Quantum Mechanics

## 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

## Quantum Theory is Representation Theory

For a first slogan (see here for slogan zero) I’ve chosen: Quantum theory is representation theory. One aspect of what I’m referring to is explained in detail in chapter 14 of these notes. Whenever you have a classical phase space … Continue reading

Posted in Favorite Old Posts, Quantum Mechanics
43 Comments

## What’s Hard to Understand is Classical Mechanics, Not Quantum Mechanics

For a zeroth slogan about quantum mechanics, I’ve chosen What’s hard to understand is classical mechanics, not quantum mechanics. The slogan is labeled by zero because it’s preliminary to what I’ve been writing about here. It explains why I don’t … Continue reading

Posted in Favorite Old Posts, Quantum Mechanics
46 Comments