Quantum Entanglement Measurement

The cluster debates quantum entanglement, wave function collapse upon observation, spooky action at a distance, and the measurement problem, referencing Bell's theorem, Schrödinger's cat, and whether it allows faster-than-light communication.

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e.g YMMV HN wikipedia.org QM puzzle.html en.m I.e arxiv.org BEC measurement particle quantum wave entanglement collapse qm observer measure particles

Sample Comments

Schroedingersat May 29, 2022 View on HN

No it doesn't.It's perfectly explained by you becoming entangled with the system when you interact with it. No spooky action at a distance needed.The wavefunction exists. Entanglement exists. Why is it so hard to extend that concept to the experimenter?

theptip Apr 8, 2024 View on HN

No. There are no “hidden local variables” (color in your example), and it really is “spooky action from a distance”.See Bell’s Theorem, this has been mathematically and experimentally proved: https://en.m.wikipedia.org/wiki/Bell's_theoremThis thing that might be confusing you is the action you are taking is collapsing the wave function of a pair of entangled particl

huula Feb 23, 2017 View on HN

It's schrodinger's cat. When you observe, its state collapses.

l33tman Jul 11, 2022 View on HN

Yes exactly. Nothing "changes" at the other end (although, there has been arguments regarding the Wigner's Friend thought experiments about this... see Guerin 2021)Just be careful when reading up on this about a subtlety here - as long as both A and B measure the same property, say "spin along Y axis", a measurement they will always both measure the opposite of, the experiment will seem just like the "unopened envelopes" popular description of entanglement w

2zcon Feb 4, 2020 View on HN

It's exactly the reason people think particles know they're being observed

tripzilch Jun 16, 2013 View on HN

What about, it's observed when its wave function collapses :-P

n4r9 Aug 28, 2015 View on HN

Yes, you're missing something. Measuring one of the particles breaks the entanglement, so that whilst you know the state of the corresponding particle, you can't affect it further.

antidesitter Jul 8, 2019 View on HN

It’s clickbait. These experiments show no inconsistency in quantum mechanics, which can be easily seen if you think about the whole system as a single wavefunction under unitary evolution. And as someone else mentioned, “observers” are part of that wavefunction. Fundamentally, they follow the same rules.

cma Mar 8, 2018 View on HN

No. See the Kochen-Specker theorem. You can choose which way to measure in ways that sort of interact with one another statistically even after two particles are far separated.

russdill May 22, 2018 View on HN

You might want to look up the quantum eraser experiments. You can have a particle interact with the system in such a way that the result of the measurement cannot be known.