Probability of Hand Going Through Table?

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SUMMARY

The discussion centers on the probability of a hand passing through a solid table, referencing concepts from quantum mechanics. Participants clarify that while quantum tunneling allows particles to pass through barriers, the likelihood of a macroscopic object like a hand doing so is astronomically low. Key points include the distinction between fermions and bosons, the role of electron interactions, and the improbability of simultaneous tunneling of all atoms in a hand. Ultimately, the consensus is that while there is a non-zero probability, it is effectively zero for practical purposes.

PREREQUISITES
  • Understanding of quantum mechanics principles, particularly quantum tunneling
  • Knowledge of particle physics, specifically the differences between fermions and bosons
  • Familiarity with atomic structure and electron behavior
  • Basic grasp of probability theory as it applies to quantum events
NEXT STEPS
  • Research "quantum tunneling" and its implications in particle physics
  • Study the differences between fermions and bosons in quantum mechanics
  • Explore the concept of "uncertainty principle" in quantum theory
  • Investigate real-world applications of quantum mechanics, such as quantum computing
USEFUL FOR

Physics students, quantum mechanics enthusiasts, and anyone interested in the implications of quantum theory on macroscopic phenomena.

  • #31
learningphysics said:
That's what I meant by conceptual difference between saying it is improbable and saying it is impossible.

When I started reading this thread, most were saying that it was impossible. I took this to mean that if the event did take place... then it violated QM.

Later on, people were saying that it was highly improbable but not impossible according to QM... I took this to mean that if the event did take place... then it did not necessarily violate QM.

So if such an event took place... an understanding like:
"According to QM the event cannot happen" would lead to the conclusion "QM is false".

But an understanding like:
"According to QM the event is highly improbable" does not lead to the same conclusion.

This is the difference I was referring to. We reach different conclusions depending on what the understanding is... impossibility or improbability.

If you tell a lay person that it is impossible for a hand to go through a table according to QM... they will take it to mean that if the event does take place, then QM is violated, because that's what impossible means. But this is a misunderstanding of QM right? Isn't it a significant misunderstanding?

Ah, but here comes the PROBLEM. This same lay person considers my broken vase scenario to be "impossible". Yet, thermodynamics says it can happen!

So, by saying to this layperson that it isn't impossible for a hand to tunnel through a table, and yet, this person would consider the vase reassemblying itself to be impossible, what have you done? You have conveyed to this person that QM is weird, mysterious, maybe mystical, or worse still, nonsense! And I will bet you that there are other things that even you would not accept would happen that physics would consider to be possible, even in the most remote sense.

This has nothing to do with "conceptual" issues. It has everything to do with being reasonable within the CONTEXT of the situation. You can only describe things in relation to other things if this is what you are truly trying to do.[1]

Zz.

[1] http://arxiv.org/abs/physics/0503229
 

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