I Understanding Bohmian Mechanics of Instrumentalists

  • #101
Demystifier said:
It's not accurate because it's not clear what do you mean by "comes into contact". Do you mean that particles come into contact, or that wave functions come into contact? Does "coming into contact" mean they arrive at the same place and touch each other, or just that they influence each other? Have in mind that particles interact non-locally in BM, so particles don't need to arrive at the same place to influence each other.
I guess I'm just wondering how a measurement occurs in BM.

I had an intuitive idea as to how a measurement occurs. For example, a ball thrown at a wall collides with the wall and leaves a mark. I thought measurements in BM were analogous. The particle is guided by the pilot wave until it collides with the detector (which gets amplified for the purpose of human observation).

Is it the case that a particle which arrives at position A, on the LHS of the detector, can result in a measurement at a position Z on the RHS? For example, in the picture, is it possible for the particle to arrive at the red position but result in the yellow measurement?

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  • #102
Lynch101 said:
For example, in the picture, is it possible for the particle to arrive at the red position but result in the yellow measurement?
That depends on the design of the lab equipment that does the amplification. If it could behave as you describe we would not use it for experiments involving interference patterns, although it might be perfectly satisfactory as a particle counting device.
(And note that only the Bohmians do not have to wrap the phrase “particle arrives at…” in interpretational disclaimers before they can use it)
 
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  • #103
Lynch101 said:
Is it the case that a particle which arrives at position A, on the LHS of the detector, can result in a measurement at a position Z on the RHS? For example, in the picture, is it possible for the particle to arrive at the red position but result in the yellow measurement?
Under certain conditions, something like that is possible. When it happens, one talks about surrealistic Bohmian trajectories, on which you can find more information by googling.
 
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  • #104
Lynch101 said:
The particle is guided by the pilot wave until it collides with the detector
The particle is always guided by the pilot wave. Collision with the detector means that pilot wave of the particle gets entangled with pilot wave of the detector, i.e. they form one big pilot wave for the joint system consisting of the particle and the detector (which itself consists of many particles).
 
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  • #105
Does the Legget-Garg inequality tell us anything about Bohmian Mechanics, or does it simply not apply?
 
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  • #106
Lynch101 said:
Does the Legget-Garg inequality tell us anything about Bohmian Mechanics, or does it simply not apply?
The LG inequality is about temporal correlations. Some people (including @A. Neumaier) were arguing in the past that BM does not correctly reproduce the quantum mechanical temporal correlations. But it is wrong. The measurable temporal correlations in QM are the same as measurable temporal correlations in BM. To understand that, one has to take into account what happens with the wave function at the time of measurement. It gets entangled with the wave function of the detector, which is responsible for an effective (apparent) wave function "collapse". More details can be found in the book F. Laloe, "Do We Really Understand Quantum Mechanics?", Appendix I.
 
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  • #107
Lynch101 said:
"'Created' seems to imply that a particle is not the effect of its antecdent state, while a particle that is 'destroyed' wouldn't be "the cause of the state that is to follow". Am I correct in that characterisation of the notions of 'create' and 'destroy'?

Of course, this would be perfectly in-keeping with the notion of an indeterministic interpretation but it would seem to require an incredibly 'extraordinary' explanation. Again, relating it back to the age-old question, how can a particle be created from absolutely nothing? How can something come from absolutely nothing? How can a particle then simply cease to have any properties whatseover?

Good points.
 
  • #108
physika said:
Good points.
No, they're not. See post #6.

(When responding to a post that was made quite some time ago, it's a good idea to read the thread first to see if others have already responded to it.)
 
  • #109
user30 said:
In physics it's that each state in a given physical world was always a fact and could never have been differently if you rewind the tape with the same initial conditions.

That is called, Fatalism, a " flavor" of determinism.

...without the need to have read subsequent posts

...
 
  • #110
user30 said:
Even in a timeless universe with no events unfolding, it would still be a complete mystery why things are correlated that show no causal connection.

all already written.

...
 
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