Questions about the de-Broglie Bohm interpretation

  • Thread starter QMister
  • Start date
46
0
Demystifier, a quick question if you have time.

The guidance equation is a function of instantaneous positions of all other particles, which themselves have positions which are unknown/unknowable. OK, that seems reasonable to me (as being a source of apparent indeterminism).

Now, the issue with that we are saying the "instantaneous position" of other particles, which gives rise to non-local influences. Why couldn't the equation be a function of their positions, but NOT their instantaneous positions? Perhaps the influence is time-delayed so that c is respected. Wouldn't that allow sufficient room for the equations to have a similar effect (i.e. apparent indeterminism but actually is deterministic)? Or perhaps it is not a past configuration that controls, but a future one. The question is whether the guidance equation demands instantaneous positions only for the influence, or could there be other solutions as well?

(Hopefully my question makes sense.)
Hi,

Your question make sense. It is a question Dirac ask himself in 1932, answered in a paper on relativistic quantum mechanics. It is the first time in the history a physicist introduce as many time variable as space coordinates variables, i.e. one couple (r,t) for each particles. Tomonaga and Schwinger then generalized this idea (a little bit enhanced by Dirak-Fock-Podolsky in their multi-time formulation of quantum mechanics) to fields. This means they associate infinitely continuous time variable to infinitely continuous coordinates positions of the field in space. The result was a Nobel and the birth of quantum field theory.

In the case of Bohm, this have been tried, and the authors claim they have a relativistic extension of bohmian mechanics. Google : multi-time Dewdney Horton to see the details. In short, they stop to describe the path of particles and start describing their world lines. Then it is relativistic if the state of the particles is'nt entangled. If it is entengled, they describe the world line of the system taken as a whole, if I remember well.

TP
 
2,460
1
As far as we talk about nonrelativistic QM of fixed number of particles, yes.
If you ask about particle creation, that's another matter, but I'll wait for your question.
Well, so if we include hidden variables in entropy then the entropy of the whole universe is not only huge right now, it was huge ever. So at one plank time after big bang everything was pre-coded?

In another words, God not only had a choice when created a Universe, but he has very wide choice?
 

Demystifier

Science Advisor
Insights Author
2018 Award
9,861
2,863
Well, so if we include hidden variables in entropy then the entropy of the whole universe is not only huge right now, it was huge ever. So at one plank time after big bang everything was pre-coded?

In another words, God not only had a choice when created a Universe, but he has very wide choice?
Yes, just as in classical mechanics.
I know what you will say, MWI does not have this "problem", ... There is no need to repeat it.
 
2,460
1
thanks.

Could you clarify what is a current state of the BM and QCD. THe thing called, if I am not wrong, "scale problem" - something about the number of particles hardron consists of. This number is not well defined and is different wheen you calculate hardron on different scales.

In general, what is a BM view on "virtual particles - are they real" problem? It is closely related to "QCD in its full weirdness" as I remember and also it reminds me the problem with the Hawking/Unruh radiation (The number of real and virtual particles are different in different accelerating frames)
 

Demystifier

Science Advisor
Insights Author
2018 Award
9,861
2,863
thanks.

Could you clarify what is a current state of the BM and QCD. THe thing called, if I am not wrong, "scale problem" - something about the number of particles hardron consists of. This number is not well defined and is different wheen you calculate hardron on different scales.

In general, what is a BM view on "virtual particles - are they real" problem? It is closely related to "QCD in its full weirdness" as I remember and also it reminds me the problem with the Hawking/Unruh radiation (The number of real and virtual particles are different in different accelerating frames)
We have already discussed that stuff too. Look at my previous answers.
 
2,460
1
Hm.. yes, but not in this thread. I did not remember any definite outcome :) of these discussions, they were quite fuzzy. That is why I was asking for some kind of a Summary.
 

Demystifier

Science Advisor
Insights Author
2018 Award
9,861
2,863
Hm.. yes, but not in this thread. I did not remember any definite outcome :) of these discussions, they were quite fuzzy. That is why I was asking for some kind of a Summary.
OK!

For QCD and the scale problem, see
https://www.physicsforums.com/showpost.php?p=2303228&postcount=18

For the Unruh effect, it is decoherence (i.e. interaction with the environment made up of objective Minkowski particles) that explains why the basis of Rindler "particles" becomes a preferred basis when the environment (measuring apparatus) is accelerated. Thus, there is some objective creation of Minkowski particles, but it is due to acceleration of objective particles existing before the acceleration. More details can be found in
http://xxx.lanl.gov/abs/0904.2287
 

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top