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[u/No-Face-7502]

[u/Physics-ModTeam]

Hey, this is a good question, but we get too many questions like this to handle as top-level threads. Please ask this in our weekly Textbooks and Resources thread, posted every Friday. You can also try /r/AskPhysics or /r/PhysicsStudents. Since we get questions like this all the time, you might also find an answer by searching the subreddit. Good luck!

[u/shermierz]

Hello! How familiar are you with superposition?

[u/No-Face-7502 → u/shermierz]

Not really

[u/shermierz → u/No-Face-7502]

Then I think you can start with superposition first. I found pretty good video on YT: https://youtu.be/PbuENwZBn8w

[u/No-Face-7502 → u/shermierz]

Thank u! I will start there

[u/OverJohn]

The Wikipedia article is worth a read. Also below is I think closest to the simplest explanation you can get, which I posted previously:

Quantum entanglement comes from applying the superposition principle to multiparticle systems (some may argue there are some hidden assumptions here though).

E.g. if we have a particle one whose state on a particular measurement is either ↑₁ or ↓₁ and particle two whose state on a particular measurement is either ↑₂ or ↓₂, then the states of the combined system on a combined measurement is either ↑₁↑₂, ↑₁↓₂, ↓₁↑₂ or ↓₁↓₂.

The superposition principle tells us though that we can linearly combine states, e.g. a↑₁↑₂ + b↓₁↓₂, where a and b are complex numbers. This corresponds to a state where measurement either yields ↑₁↑₂ or ↓₁↓₂, so the particles are correlated as they must be both "up" or both "down" after the combined measurement.

As pointed out by another user this very simple explanation doesn't show how quantum entanglement results in correlations that are non-classical. This is because you need to be a bit more canny with which measurements you choose in order to get these non-classical correlations. An explanation of how non-classical correlations arise from entanglement can be found again on Wikipedia.

[u/liccxolydian]

English language Wikipedia is actually a pretty good overview. That's actually true of many topics in physics.

[u/No-Face-7502 → u/liccxolydian]

I already read it but I didn’t understand everything

[u/liccxolydian → u/No-Face-7502]

Then you'll need to go more basic. Did you study physics in high school?

[u/No-Face-7502 → u/liccxolydian]

I did but we rarely learned about quantum physics

[u/GladAbbreviations553]

Do you have a CS degree? If so you probably know enough math to start following theoretical minimum lectures on YouTube alongside their books. Start with Classical Mechanics first.

If you don't know any math follow this guide, but it'll take time before you get to quantum mechanics: https://www.susanrigetti.com/physics