Quantum Tunneling VS Water (or any other) Waves

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Discussion Overview

The discussion explores the analogy between quantum tunneling of electrons and the behavior of water waves when encountering barriers. Participants examine whether water waves can exhibit similar leakage through barriers as electrons do in quantum mechanics, considering various conditions and types of barriers.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question whether a water wave would leak through a watertight barrier, suggesting that under such conditions, it would not.
  • Others propose that if a barrier is not perfectly rigid, such as a flexible plastic film, water waves could pass through, but they argue this does not relate to quantum mechanics.
  • A participant introduces the concept of evanescent waves from classical electromagnetism as a better analogy for quantum tunneling, noting that energy can be transmitted through thin media under certain conditions.
  • One participant argues that for large objects like water waves, the probability of all particles tunneling simultaneously is so low that it is effectively impossible.
  • Another participant mentions superfluids, stating that they can leak through barriers in a way that demonstrates quantum effects in a macroscopic context, although this effect diminishes with the height of the barrier.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the analogy between quantum tunneling and water waves. Multiple competing views are presented regarding the behavior of waves and barriers, with some asserting that water waves cannot tunnel while others suggest specific conditions under which they might exhibit similar behavior.

Contextual Notes

Discussions involve assumptions about the rigidity of barriers and the nature of the waves involved. The implications of superfluid behavior and the conditions under which evanescent waves occur are also noted but not resolved.

Who May Find This Useful

Readers interested in the intersections of classical and quantum physics, wave behavior, and the implications of superfluidity may find this discussion relevant.

QuantumMan
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Would a water wave leak just like an electron with a barrier?
 
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QuantumMan said:
Would a water wave leak just like an electron with a barrier?

Assuming a watertight barrier, no not at all.
 
Drakkith said:
Assuming a watertight barrier, no not at all.

I'm not saying water is leaking through.

Say a 'water tight' barrier is surrounded by water on both sides. With a wave hitting one side.

Would there be a wave on the other side like in quantum tunneling.
 
If the barrier is perfectly rigid, then no water (pressure) waves will pass through no matter the thickness. If the barrier is not rigid, say it's made out of a thin film of flexible plastic, then of course the water wave can pass through. But this has nothing to do with quantum mechanics.

A better analogy for quantum-mechanical tunneling comes from classical E+M. When an EM wave reflects off of the boundary between two media at an angle greater than the critical angle, an evanescent wave forms in the second medium, and if the second medium is thin enough, the evanescent wave can actually transmit some energy from the EM wave through the second medium. The phenomenon is called "evanescent wave coupling." See http://en.wikipedia.org/wiki/Total_internal_reflection and http://en.wikipedia.org/wiki/Evanescent_wave
 
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FOr a large object like a water wave it would require an impossible coincidence of every single particle in it tunneling at eactly the right time and then the ones behind them doing the same ... and doing do with all the protons and electrons remaining together. So improbably that it is impossible. It is just as impossible for even one atom with an electron AND a proton to do the same even if possible for indepenedent electrons to do it.
 
Superfluids (like liquid helium) can leak through a barrier. Just put a wall in a vessel with a superfluid then push it onto it. Some fluid will "climb" on the wall and fall on the other side, no matter how high the wall is, however this effect will vanish exponentialy with the height of the wall. This is an interesting phenomenon when a quantum-mechanical effect displays directly in a macroscopic world.
 

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