Audio note: this article contains 159 uses of latex notation, so the narration may be difficult to follow. There's a link to the original text in the episode description.

Today's post is in response to the post "Quantum without complications", which I think is a pretty good popular distillation of the basics of quantum mechanics.

For any such distillation, there will be people who say "but you missed X important thing". The limit of appeasing such people is to turn your popular distillation into a 2000-page textbook (and then someone will still complain).

That said, they missed something!

To be fair, the thing they missed isn't included in most undergraduate quantum classes. But it should be.[1]

Or rather, there is something that I wish they told me when I was first learning this stuff and confused out of my mind, since I was a baby [...]

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Outline:

(02:18) Quantum mechanics 101

(07:36) Upshots

(08:32) Statistical mechanics 101

(12:20) Welcome to the matrix

(13:44) Density matrices

(20:23) So can I brag to people that Ive resolved all the multiverse/decoherence issues now?

(21:05) Who ordered that?

The original text contained 9 footnotes which were omitted from this narration.

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First published:
January 17th, 2025

Source:
https://www.lesswrong.com/posts/oa7tSF497vSo7dTh2/the-quantum-red-pill-or-they-lied-to-you-we-live-in-the

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Narrated by TYPE III AUDIO.

“The quantum red pill or: They lied to you: we live in the (density) matrix” by Dmitry Vaintrob

LessWrong (30+ Karma)

“The quantum red pill or: They lied to you: we live in the (density) matrix” by Dmitry Vaintrob