How do deterministic Bohmian/Pilot Wave Theories Handle These?

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Bohmian Mechanics (BM) is discussed in relation to its deterministic nature and how it addresses quantum fluctuations and particle decay. The theory does not currently have a comprehensive framework for virtual particles, as they are often considered artifacts of mathematical methods rather than physical entities. In terms of particle decay, particularly for unbound neutrons, some interpretations of BM suggest that such processes could be predetermined, although a satisfying Bohmian interpretation of quantum field theory is still under development. The discussion highlights the complexity of integrating BM with established quantum theories and the ongoing debate about its validity and applicability. Ultimately, the conversation reflects a desire for deeper understanding of BM's implications in quantum physics.
  • #121


Dmitry67 said:
But they are not hidden in GLET, because, as I understand, GLET gives different predictions then SR
For example, in SR if I jump ito BH I am torn apart by the tidal forces, but there is no surface
In your theiry you hit the surface

There are some additional terms, which lead to different predictions, but, surprise, purely formal the theory has also a Minkowski symmetry (that of the vacuum solution, for appropriate signs of my cosmological constants). So the different predictions are not about preferred frames.

Then, the additional terms are mainly cosmological in nature. They do not depend on derivatives of the metric, like Einsteins cosmological term. They become large only in cosmological situations and in situations where the harmonic coordinates otherwise would become infinite. For PPN, I would suggest that the relevant parameters are simply too small to be observable.

The remarkable thing is, of course, that however small they are, the surface remains, and the big bang singularity cannot happen too.
 
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  • #122


Dmitry67 said:
Ilja, well, our understanding of beauty is quite different. I have to admit, I am shocked by the fact that preffered frame for you is a beauty - not an uglyness.

The beauty of the preferred frame was simply a joke. I understand very well that more symmetric things are more beautiful, and, whenever I have a variant with relativistic symmetry, nothing otherwise worse with it, I certainly prefer it.

But one thing is the preference for symmetry, another thing that the situation with realism, the violation of Bell's inequality, and pilot wave theory give very strong support for a preferred frame - and that preferred frame I had postulated even earlier for completely different reasons. It is quite clear that one likes to see that the own ideas obtain independent strong support.
 
  • #123


So what happens if I jump into a black hole, or, how you call it, a frozen star?
Or, what happens to an observer staying on the surface of a 'frozen star'?

Being indistinguishable from SR requires that observer in your GLET witness all effects, predicted by SR: ergosphere, blue sheet at the Cachy horizon, and even watching the naked Kerr ring - in all its beauty.
 
  • #124


Dmitry67 said:
So what happens if I jump into a black hole, or, how you call it, a frozen star?
Or, what happens to an observer staying on the surface of a 'frozen star'?

Being indistinguishable from SR requires that observer in your GLET witness all effects, predicted by SR: ergosphere, blue sheet at the Cachy horizon, and even watching the naked Kerr ring - in all its beauty.

The observer will hit the surface and certainly not survive this. The temperature of the surface itself, in the relativistic frame, will be very hot, because it is heated by infalling matter. But, as far as I understand, not hot enough to be visible from outside.
 
  • #125


DrChinese: I've got you thinking eh? After reading the OP and a bit of thought, here are the answers coming from my gut:

PRESUMING quantum retrocausality and requiring an absorber for each emitted particle...

A) Recall that no space is empty, but filled with waves (making no distinction between EM and wavefunctions here) coming from every direction. Suppose constructive interference is not relegated to a single system's wavefunction, but under certain (extremely rare) circumstances the wavefunctions of multiple systems could interfere to create the appropriate absorbers for the respective emitted particles of each system. This would provide a deterministic mechanism for virtual particles.

B) Under these presumptions particle decay could simply be described as a (deterministic) probability function of the emitter "encountering" the appropriate absorber via the Poisson distribution. The longer the half-life, the rarer the appropriate absorber.

These presumptions would also (stated from pop-sci level of knowledge of black holes) explain black hole radiation while preserving information: allow particle X to pass the horizon. Now, a created particle/antiparticle pair (X*, Y) straddling the horizon could only occur if there was the appropriate absorber within the horizon; in this case, Y would also fall into the black hole, headed for X. X* escapes, while X and Y annihilate, thereby both preserving information and obeying the no-cloning principle.:wink:
 
  • #126


rjbeery said:
DrChinese: I've got you thinking eh? After reading the OP and a bit of thought, here are the answers coming from my gut:

PRESUMING quantum retrocausality and requiring an absorber for each emitted particle...

A) Recall that no space is empty, but filled with waves (making no distinction between EM and wavefunctions here) coming from every direction. Suppose constructive interference is not relegated to a single system's wavefunction, but under certain (extremely rare) circumstances the wavefunctions of multiple systems could interfere to create the appropriate absorbers for the respective emitted particles of each system. This would provide a deterministic mechanism for virtual particles.

B) Under these presumptions particle decay could simply be described as a (deterministic) probability function of the emitter "encountering" the appropriate absorber via the Poisson distribution. The longer the half-life, the rarer the appropriate absorber.

These presumptions would also (stated from pop-sci level of knowledge of black holes) explain black hole radiation while preserving information: allow particle X to pass the horizon. Now, a created particle/antiparticle pair (X*, Y) straddling the horizon could only occur if there was the appropriate absorber within the horizon; in this case, Y would also fall into the black hole, headed for X. X* escapes, while X and Y annihilate, thereby both preserving information and obeying the no-cloning principle.:wink:

Yes, it is pretty interesting that the probability waves are the main thing that act as if they are "real" at all times... until there is a wave function collapse and one of the possibilities are selected. So it would be natural to presume that just like in an ocean, waves from different particles can overlap and then there is either constructive or destructive interference. In this model, the "virtual" particles would somehow represent suitable wave crests to use an analogy. The problem as I see it is that implies that there are more wave crests near large objects as compared to empty space - assuming that the wave strength diminishes with distance - and there is nothing to indicate that this is the case. But who knows, maybe there are effects which are different in open space versus near Earth, where most experiments are done. (I believe that it has been ruled out that dark matter is ZPE.)

And also interesting: where are the hidden variables? In Bohmian interpretations, they reside non-locally. In MWI, they are in other worlds (being a little loose here). In Retro-causal interpretations, in the future. But they all have similar ideas in terms of supplying the missing ingredients that we hope would "complete" QM. Assuming, of course, that it is possible to complete QM, which many doubt - and I can understand that position too. :smile:

So one of the reasons I am interested in Demystifier's work - and that of others in BM - is to understand how it applies to some of the other phenomena in the quantum world. So if I ask him about radioactive decay - how is that "caused" in BM - then the same question would also apply in retro-causal (time symmetric) interpretations. There must be an advanced wave and a retarded wave for the W boson as well. And of course, the standard model is still silent on this - which also is sensible given the current state of experiments.
 
  • #127


Does BM allow one to in principle manipulate the probabilities that standard quantum mechanics predicts? BM is deterministic and an observers consist of particles, so why not?
 
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  • #128


Ilja said:
The observer will hit the surface

Good. In GR this does NOT happen
So, your GLET and GR give DIFFERENT predictions for some experiments, do we agree?
Why not then put it into the formalism and check if it fits the experimental data?
 
  • #129


DrChinese said:
probability waves are the main thing that act as if they are "real" at all times... until there is a wave function collapse and one of the possibilities are selected.
It seems that this language is an artifact of CI. There is no "until"; each particle has a discrete path at all times. A pilot wave is directly equivalent (in my mind, but I may be wrong) to pure retroaction, which is the framework within which I provided my answer.

DrChinese said:
The problem as I see it is that implies that there are more wave crests near large objects as compared to empty space
Because the waves are retrocausal, distance to a potential absorber may be disregarded. In other words, your objection is only as detectable as the Universe is transparent. Something just occurred to me - this model would imply that Hawking radiation would not originate from the horizon at all, but would rather spontaneously occur all over the Universe.:bugeye:

DrChinese said:
where are the hidden variables?
The hidden variables exist in the future presuming that pilot wave theory and pure quantum retrocausality are equivalent. If they are not, then I am defending the wrong interpretation!:-p
 
  • #130


DrChinese: Rereading post number 126, it is clear that you are drawing a distinction between retrocausal theories and BM so it is possible that I am in fact defending the wrong interpretation as framed by your question. It is my position that BM and retrocausal interpretations are equivalent; I guess I would like to add to your questioning and ask any BM advocates to explain the difference between the following two pictures:

Under retrocausality:
Code: 
[FONT="Fixedsys"]
t=1: Ex~~~~~ A
t=2: E x~~~~ A
t=3: E  x~~~ A
t=4: E   x~~ A
t=5: E    x~ A
t=6: E     x A

Under non-retrocausal pilot wave theory:
Code: 
[FONT="Fixedsys"]
t=1: Ex~     A
t=2: E x~    A
t=3: E  x~   A
t=4: E   x~  A
t=5: E    x~ A
t=6: E     x A

Where E is the emitter, x is the particle, ~ is the (pilot)wave function, A is the absorber and of course t is the time progression. Does ~ precede x in the time dimension or not? I have have difficulties with either answer unless I presume retrocausality...
 
  • #131


rjbeery said:
DrChinese: Rereading post number 126, it is clear that you are drawing a distinction between retrocausal theories and BM so it is possible that I am in fact defending the wrong interpretation as framed by your question. It is my position that BM and retrocausal interpretations are equivalent; I guess I would like to add to your questioning and ask any BM advocates to explain the difference between the following two pictures:

Under retrocausality:
Code: 
[FONT="Fixedsys"]
t=1: Ex~~~~~ A
t=2: E x~~~~ A
t=3: E  x~~~ A
t=4: E   x~~ A
t=5: E    x~ A
t=6: E     x A

Under non-retrocausal pilot wave theory:
Code: 
[FONT="Fixedsys"]
t=1: Ex~     A
t=2: E x~    A
t=3: E  x~   A
t=4: E   x~  A
t=5: E    x~ A
t=6: E     x A

Where E is the emitter, x is the particle, ~ is the (pilot)wave function, A is the absorber and of course t is the time progression. Does ~ precede x in the time dimension or not? I have have difficulties with either answer unless I presume retrocausality...

It was Demystifier who was mentioning the there might be a component of the Bohmian interpretation which relates to the future, and I believe we will get a chance to hear more about that soon. So I wasn't going to push in that area as he will tell us about it when he is ready.

If I were strictly guessing, I might imagine that non-local influences would look, in a lot of ways, as if it were arriving from the future.

A follow-up question, for Demystifier or other BM knowledgeable person: The guidance equation is a function of the configuration of the system, Q(t) = (Q1(t), · · · ,QN(t)). What is not clear is whether particle Qn's influence decreases with distance (sorta like an inverse square effect), or not. Anything anyone could add on that?
 
  • #132


Dmitry67 said:
Good. In GR this does NOT happen
So, your GLET and GR give DIFFERENT predictions for some experiments, do we agree?
Why not then put it into the formalism and check if it fits the experimental data?

We do agree that the predictions are different for some experiments. But the parameter Y of my theory has to be extremely small to allow for an early stage of the universe, so I'm very sure that it will not give observable effects in the PPN. I agree that one should write down this and get some numbers, but my priorities have been (and are yet) different, simply because I'm sure that PPN will lead to some observable differences. And, as I have already mentioned, the effects will not be those responsible for preferred frame effects.
 
  • #133


Ilja, thank youfor clarification.
(even for me it is very hard to believe that there are no observable effects when there is an obvious difference for the BH. There are some data on the strong gravitational fields, like tight binary pulsars slowdown et cetera)
 
  • #134


1) Certainly the retro-causal action would solve the notoriously difficult NP Complete algorithm problem.
If collisions of particles etc are to be determined rather than 'just happen' there needs to be a solution to
calculate where and when. Even a computer has massive NP problems with that (nearly as bad as super determinism). Retro causality would be great to have.

2) BM: "A simple preferred frame does the job" - I'll go for an informational one if we are allowed to start having those!
 
  • #135


Dmitry67 said:
Ilja, thank youfor clarification.
(even for me it is very hard to believe that there are no observable effects when there is an obvious difference for the BH. There are some data on the strong gravitational fields, like tight binary pulsars slowdown et cetera)

Simply there are two free parameters X, Y, and if they approach zero we obtain exactly the Einstein equations. Thus, making them sufficiently small is sufficient to get the Einstein equations (but not GR) with any required accuracy.

It is harder to understand why there nonetheless remain differences. But these differences are connected with infinities: The big bang singularity and infinite redshift (even if the last is not considered by standard GR as something infinite).
 
  • #136


What is a minimum value of X and Y to prevent the collapse?
 
  • #137


Dmitry67 said:
What is a minimum value of X and Y to prevent the collapse?
X is arbitrary, non-zero, Y should be > 0 to prevent collapse. Any value >0 does it.

There is a very small maximum for Y, because else the dense states of the early universe we observe would be impossible.
 
  • #138


Hm, so do you believe that in fact Y is >0, Y=0 or you don't know?
The reason why I asking is that if Y=0 and your theory becomes equialent to SR,
then a preferred 'timelike' frame becomes spacelike inside the black hole,
and normal particles will behave like tachions inside the horizon relative to that frame.

It is possible that as that frame is undetectable, then it is remains undetectable in your BM theory even under such extreme conditions. But it this case it is quite interesting and beautiful. Spacelike preferred frames... Did you think about it?
 
  • #139


Dmitry67 said:
Hm, so do you believe that in fact Y is >0, Y=0 or you don't know?
The reason why I asking is that if Y=0 and your theory becomes equialent to SR,
then a preferred 'timelike' frame becomes spacelike inside the black hole,
and normal particles will behave like tachions inside the horizon relative to that frame.

It is possible that as that frame is undetectable, then it is remains undetectable in your BM theory even under such extreme conditions. But it this case it is quite interesting and beautiful. Spacelike preferred frames... Did you think about it?

I believe that Y>0 but extremely small.

But even for Y<=0 the situation is not as you describe. The complete physical part (according to this version of the theory) is then only a part of the complete GR solution. Absolute time reaches infinity at a part which looks unproblematic from GR point of view.

The interpretation is quite unproblematic: The collapsing star becomes frozen. Nothing moves there. The infalling observer will never experience the moment of proper time after his freezing.
 
  • #140


Your position is inconsistent.

You claim that Y is small and hence there GLET give an identical results for almost all experiments. And yet, you say that there is a dramatic difference for the strong fields: no collapse in your theory vs collapse.

If there is no collapse your theory should produce different results for the strong gravity fields: http://en.wikipedia.org/wiki/Tests_of_general_relativity#Strong_field_tests
 
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  • #141


Ilja said:
The interpretation is quite unproblematic: The collapsing star becomes frozen. Nothing moves there. The infalling observer will never experience the moment of proper time after his freezing.

If falling observer's time is slowed down in the same ratio as the star, then for that observer star won't look frozen. So what would he see?
 
  • #142


Dmitry67 said:
If falling observer's time is slowed down in the same ratio as the star, then for that observer star won't look frozen. So what would he see?


See here:

http://arxiv.org/abs/gr-qc/0609024
 
  • #143


Count Iblis, it is about GR
Ilja's GLET is different :)
 
  • #144


P.S.
But the article was quite interesting.
I was thinking that at least with non-rotating BH everything was clear :)
 
  • #145


Ilja said:
I understand very well that more symmetric things are more beautiful, and, whenever I have a variant with relativistic symmetry, nothing otherwise worse with it, I certainly prefer it.
So, do you find something worse with http://xxx.lanl.gov/abs/0811.1905 ?
 
  • #146


DrChinese said:
It was Demystifier who was mentioning the there might be a component of the Bohmian interpretation which relates to the future, and I believe we will get a chance to hear more about that soon.
Actually, you can see about that in my older paper too:
http://xxx.lanl.gov/abs/0811.1905

DrChinese said:
A follow-up question, for Demystifier or other BM knowledgeable person: The guidance equation is a function of the configuration of the system, Q(t) = (Q1(t), · · · ,QN(t)). What is not clear is whether particle Qn's influence decreases with distance (sorta like an inverse square effect), or not. Anything anyone could add on that?
No, it doesn't decrease with distance. But the average influence decreases with the number of environment degrees of freedom that destroy coherence, which, in turn, may (or may not) decrease with distance.
 
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  • #148
  • #149


Demystifier said:
Here it is:
http://xxx.lanl.gov/abs/0904.2287

In this paper a quantum many particle state depends on a many spacetime positions vector and the coordinate degeneracy of the quantum state originates the quantum behaviors of QFT. This approach is very reminescent of another deterministic theory publicated about a mouth ago: http://arxiv.org/pdf/0903.3680 . In this case the degeneracy of the single particle coordinates comes from the de Broglie assumption of periodicity, which is exact for free fields. A deep relationship between pilot wave or Bohmian interpretation and the de Broglie approach to QM from these interesting papers.
 
  • #150


Demystifier said:
Here it is:
http://xxx.lanl.gov/abs/0904.2287
Hi Demystifier,

I just had a look through this paper. In section B you attempt to
set up an inf-dim space relying on a measure of the form:
<br /> Dx ~:=~ \prod_{n=1}^\infty \; d^4x_n<br />
(I'm just paraphrasing your equations 28,30,31, etc.)

If I've understood what you're trying to do (forgive me if I've
got it wrong), you're taking the ordinary Lebesgue measure dx
on a 1-particle configuration space, then the corresponding Lebesgue
measure on a N-dimensional product of these spaces (which is fine
so far), and then assuming that this remains valid for N\to\infty.
However, it's a theorem that a non-trivial Lebesgue measure on an
inf-dim space of this kind does not exist. See, e.g.,

http://en.wikipedia.org/wiki/There_is_no_infinite-dimensional_Lebesgue_measure

The essence of the proof is that if we demand the measure be translation-invariant,
(roughly, that dx = d(x+c) for c constant), then the measure is trivial (zero).

Exactly the same problem occurs in path integrals, forcing people to adopt
Wiener (Gaussian) measure instead, which is not translation-invariant.
(This issue is also related to the stuff currently being discussed over in the
other thread about "unbounded operators".)
 

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