Doesn't QM allow for FTL travel?

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    Ftl Qm Travel
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Discussion Overview

The discussion revolves around the implications of quantum mechanics (QM) on the possibility of faster-than-light (FTL) travel. Participants explore the behavior of particles, such as electrons, in relation to their probabilistic locations and the concept of measurement in QM, questioning whether this could allow for FTL phenomena.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that since an electron has a probability of being found in different locations, it might appear to travel faster than light between measurements taken with a small delay.
  • Another participant agrees that while the electron may not 'travel' in the traditional sense, its instantaneous appearance at a distant location could be interpreted as having effectively covered that distance faster than light.
  • A third participant expresses uncertainty about their previous explanation and provides references to past discussions and papers on related topics, indicating a desire for more experienced input on the matter.
  • A fourth participant acknowledges the possibility of appearances of FTL travel but emphasizes that relativity prohibits communication faster than light, maintaining that causality is preserved despite these appearances.

Areas of Agreement / Disagreement

Participants express differing views on whether QM allows for FTL travel, with some arguing that the probabilistic nature of particles could imply FTL effects, while others assert that relativity constraints prevent actual FTL communication or causality violations. The discussion remains unresolved.

Contextual Notes

Participants reference specific conditions under which FTL appearances might occur, but these conditions are not fully detailed. The implications of measurement and the role of probability in QM are also acknowledged but not exhaustively explored.

Raap
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My knowledge of QM is far from great, but I can't figure out what I'm missing here.

When looking for e.g. an electron, it has a certain probability to be at a certain location, right? So how does *not* this allow for the electron to travel faster than light?

If I take two measurements, one taken with a tiny, tiny delay, couldn't I potentially find the electron at one spot with the first measurement, then with the second measurement find it on the completely opposite side, further away than light could have traveled within that small time-delay between the measurements?
 
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I understand what you're saying, but I'm still not sure how this rules out ftl travel. Granted, the electron might not 'travel' as such, but if it appears at a location more distant than one which light could have traveled in the time between measurements, even if the electron itself didn't travel there but rather 'teleported' to or 'was found there', then it has effectively covered that distance faster than the speed of light, right?
 
I'm sorry, Raap and everyone else. I deleted my message since I wasn't happy with my explanation. I had hoped you hadn't read it yet, since I found it to be just confusing. Sorry for making the thread confusing by it's deletion.

I have found this past thread that may be of help to you. Check out Zapperz's post.

https://www.physicsforums.com/showthread.php?t=97604

edit:

Here is another paper discussing "superluminal tunneling" written by an author of a paper mentioned in the thread above:

H. Winful, Phys. Rep. v.436, p.1 (2006).

I think the best I can do is to provide you with this "reading list" of threads and papers.:rolleyes: I'll leave the discussion and explanation to someone with more experience explaining the effect.
 
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Sure, it will have 'traveled' faster than light if you see it here than there in a short time. But if your going into the muddy details remember that relativity says you cannot 'communicate' faster than light. Specific conditions can be contrived where objects appear to be traveling faster than light and that's fine, because you still cannot communicate faster than light and causality is maintained.
 

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