The Delayed Choice Quantum Eraser, Debunked

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The delayed choice quantum eraser is one of the weirdest, if not THE weirdest, experiments in quantum mechanics. It supposedly rewrites the past because the choice of a measurement changes what happened in another measurement earlier. In this video I explain why this is not what's happening. The quantum eraser isn't remotely as weird as you may have heard.

Sean Carroll's blogpost is here: https://www.preposterousuniverse.com/blog/2019/09/21/the-notorious-delayed-choice-quantum-eraser/

Technical remark: You can find a lot of webpages saying that the envelope of the double-slit interference pattern is that of the single-slit diffraction pattern. Note that this is is only approximately correct.

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0:00 Intro
1:45 The Double Slit
4:17 Entanglement
4:53 The Quantum Eraser
9:03 What they didn't tell you
11:45 Sponsor Message

#physics #quantum