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shminux comments on An explanation of the 'Many Interacting Worlds' theory of quantum mechanics (by Sean Carroll and Chip Sebens) - Less Wrong Discussion

5 Post author: Ander 18 December 2014 11:36PM

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Comment author: shminux 19 December 2014 03:26:14AM 3 points [-]

The animations are pretty, but the article is short on actual explanations. How does adding a detector to one of the slits kill the interference pattern? How exactly do the particles interact in the configuration space? How does entanglement arise in this picture? Hopefully these issues are addressed in the actual paper, though it's not at all obvious from the abstract.

Comment author: Ander 19 December 2014 07:09:43AM 1 point [-]

Agreed, its very much an explanation to the layman, not a technical article.

Comment author: [deleted] 20 December 2014 09:00:00AM 0 points [-]

Presumably, if you put a detector in front of one of those slits, the particles cannot pass through both slits, and thus you wouldn't have those two moving collections of particles. You would have one moving collection, which would simply fan out without interference.

Comment author: shminux 20 December 2014 05:28:53PM *  2 points [-]

Surely in some worlds you detect a particle and in others you don't, so there are plenty of particles going through each slit on aggregate.

Comment author: [deleted] 20 December 2014 09:18:48PM 0 points [-]

Right. But I think the idea is there are two groups of particles when both slits are open. When one is blocked a particle detector, they can't go through both slits.

With a detector in one of the slits, you will only see one group, not the unmeasured state with both groups.

Comment author: shminux 21 December 2014 05:05:12PM 1 point [-]

That's not how the double-slit experiment works. Both slits remain open at all times. The detector only detects the passage of the particle through one of the slits.

Comment author: [deleted] 21 December 2014 05:57:06PM 0 points [-]

Right.

I'm not saying I'm an expert, or even that I'm remotely intriguied by Interacting Many Worlds.

My point is, as long as the photon(s) have been undetected, they can travel through both slits.

As soon as you detect the photon at one of the slits, it cannot, as it has been measured at one of the slits.