= 27d567bc2d48d9f40e9ccc20ea370b15)
Slider comments on Open thread, 9-15 June 2014 - Less Wrong Discussion
You are viewing a comment permalink. View the original post to see all comments and the full post content.
= 783df68a0f980790206b9ea87794c5b6)
Loading…= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
Powered by Reddit
= f037147d6e6c911a85753b9abdedda8d)
You are viewing a comment permalink. View the original post to see all comments and the full post content.
Comments (239)
The wavefunction is the same object shared by all universes, correct? Thus a point's spatial neighborhood in one universe is not the full neighborhood of the point. I would imagine (if it's a coherent notion) taking a derivate only "within one universe" would have a different result than taking it with the full wavefunction.
Wouldn't an air molecule already going one way need a separate cause to be going that way (as in something that pushes it that way (probably another air molecule))? And wouldn't that put it simply further in configuration space (ie make interference less likely)? I have still trouble imagining when interference happens and when not. You need a path in configuration space to connect two points to have interference? And if the distance is big there are more chances for the intervening configurations to spoil the interaction?
It seems the air gets scrambled. I guess any device that could detect the scrambling would be as good as detecting the particle directly?
I meant the universe's neighborhood, at taking the derivative of the universe's wavefunction at that point.
Since the wave function is continuous, if you look at a universe with a particle nudged just a little bit, the wave function won't change much. It's not like you're moving that particle very far.
No. If the air only ended up in that orientation if the particle went in a particular direction, then the system would decohere, and the detector would be unnecessary. Since the air can end up in the same orientation either way, there's no way to detect it.
If the photon is going through the other slit it's several molecule lengths away. So the molecule just curves/collides with empty space as if the photon was there? I don't understand how it can touch the air and not decohere.
The interactions are weak. If we had some super-sensitive air pressure detector that could tell which slit the photon had gone through, we'd get the same results as when we measure which slit the photon has gone through (that is to say, no interference). But actually such a thing is impossible; maybe a few air molecules close to the photon path will get their state entangled with the photon state, but they don't interact enough with other air molecules for the entanglement to spread through the whole room. So you get a case rather like the one where you record which slit the photon went through but then destroy that information without reading it - and you do see the interference.
There's another universe where the air was already going in that direction. Since the photon isn't going to nudge it much, it's a really similar universe, so it has about the same wavefunction as the universe you were looking at to begin with.