muppet said:
What I'm saying is based on points made in his posts that you appear to be missing.
I know exactly what it said, and I didn't claim that deBB was incompatible with QFT. I didn't quote you out of context because the sentence I omitted doesn't run contrary to the point I was making, which is that a great deal of research into deBB isn't actually driving physics forward because it's busy trying to replicate results we already have.
I should have said: 'Most of the presentation of technical material within the paper was concerned with explaining the predictions of nonrelativistic QM in terms of particles subject to dynamics described by the guidance equation', but it would have made a clumsy parenthesis. You will find that I made specific references elsewhere to the nature of the discussion in that paper of relativistic extensions.
I already acknowledged and apologised for my error in the other thread, in which you made a similarly crass error. As pointed out above, I was aware of the other sections. The conclusion I drew is not that deBB is incompatible with QFT as you claim (perhaps ironically, given the nature of this accusation) but that as a predictive tool deBB in its present state has substantially less power and utility than the orthodox methods employed by the majority of researchers.
OK.
I understand perfectly well that in orthodox QM (hereafter just QM) probabilities arise as a postulate that works. The reason I'm more forgiving of it in QM is that in QM the implication is that nature is intrinsically probabilistic; that this is, in fact, what nature is like. In deBB you need to explain how a deterministic system gives rise to the probabilistic distribution we observe, and neither of the initial papers provided an unambiguous or complete answer to that question. When you provided a link to a more detailed presentation of how probabilities might arise, I ackowledged it. The point of that very paragraph was to acknowedge it, and explain my criticism in terms of the previous papers. To repeat that one sentence and suggest that I was blindly repeating the same accusation in the face of a more complete answer was -dare I say it- quoting me out of context.
If you read my original post you'll find that whilst I was fairly emphatic in the position I adopted, I didn't say anything that implied you were an idiot. I just disagreed with you, and pointed out that you hadn't really responded to the present line of argument. My tone has self-evidently become more terse throughout these posts, in direct response to your abrasive manner and evasion of several clear requests. I also think you'll find that when you've fleshed out or elaborated upon deficiencies in the original links, I've responded to that appropriately. By contrast, you seem to be accusing me of making claims that I simply haven't, such as that deBB is incompatible with QFT. If you think that this is what I'm saying or have said at any point, then either I haven't acheived the clarity I desired or you have misunderstood me. So please, allow me one further opportunity to make my position clear, without any intention of sounding patronising:
I am NOT claiming that deBB is false, or that it is incompatible with QFT, or that it has no merit. I'm not even claiming that it is in principle impossible that it yields new physics, and I would be extremely interested to hear the outcome of any experiment in which the predictions of deBB differed from those of QM.
I AM claiming that as a predictive tool, deBB is substantially less useful than the paradigm within which most researchers operate. I base this claim in particular on the fact that the Standard Model has been subjected to incredible experimental scrutiny over the last 40 years, and passed all tests with flying colours, wheras deBB is now beginning to consider how it can be extended to include the standard model. I consider that a deficit of four decades' worth of research amounts to a substantial body of science that orthodox methods have yielded and deBB has not.
I DO also claim that such attempts as there are to formulate a bohmian QFT have less utility than their orthodox counterparts. You have the particular opportunity to convince me that this statement is false, by providing links to published works in which deBB theory reproduces predictions made by orthodox QFT and experimentally verified. This, and in my present opinion only this, constitutes sufficient evidence to refute that claim. Once again, I suggest you start with reference to calculation of those quantities suggested by reilly.
muppet said:
What I'm saying is based on points made in his posts that you appear to be missing.
I know exactly what it said, and I didn't claim that deBB was incompatible with QFT. I didn't quote you out of context because the sentence I omitted doesn't run contrary to the point I was making, which is that a great deal of research into deBB isn't actually driving physics forward because it's busy trying to replicate results we already have.
I should have said: 'Most of the presentation of technical material within the paper was concerned with explaining the predictions of nonrelativistic QM in terms of particles subject to dynamics described by the guidance equation', but it would have made a clumsy parenthesis. You will find that I made specific references elsewhere to the nature of the discussion in that paper of relativistic extensions.
I already acknowledged and apologised for my error in the other thread, in which you made a similarly crass error. As pointed out above, I was aware of the other sections. The conclusion I drew is not that deBB is incompatible with QFT as you claim (perhaps ironically, given the nature of this accusation) but that as a predictive tool deBB in its present state has substantially less power and utility than the orthodox methods employed by the majority of researchers.
OK.
I understand perfectly well that in orthodox QM (hereafter just QM) probabilities arise as a postulate that works. The reason I'm more forgiving of it in QM is that in QM the implication is that nature is intrinsically probabilistic; that this is, in fact, what nature is like. In deBB you need to explain how a deterministic system gives rise to the probabilistic distribution we observe, and neither of the initial papers provided an unambiguous or complete answer to that question. When you provided a link to a more detailed presentation of how probabilities might arise, I ackowledged it. The point of that very paragraph was to acknowedge it, and explain my criticism in terms of the previous papers. To repeat that one sentence and suggest that I was blindly repeating the same accusation in the face of a more complete answer was -dare I say it- quoting me out of context.
If you read my original post you'll find that whilst I was fairly emphatic in the position I adopted, I didn't say anything that implied you were an idiot. I just disagreed with you, and pointed out that you hadn't really responded to the present line of argument. My tone has self-evidently become more terse throughout these posts, in direct response to your abrasive manner and evasion of several clear requests. I also think you'll find that when you've fleshed out or elaborated upon deficiencies in the original links, I've responded to that appropriately. By contrast, you seem to be accusing me of making claims that I simply haven't, such as that deBB is incompatible with QFT. If you think that this is what I'm saying or have said at any point, then either I haven't acheived the clarity I desired or you have misunderstood me. So please, allow me one further opportunity to make my position clear, without any intention of sounding patronising:
I am NOT claiming that deBB is false, or that it is incompatible with QFT, or that it has no merit. I'm not even claiming that it is in principle impossible that it yields new physics, and I would be extremely interested to hear the outcome of any experiment in which the predictions of deBB differed from those of QM.
I AM claiming that as a predictive tool, deBB is substantially less useful than the paradigm within which most researchers operate. I base this claim in particular on the fact that the Standard Model has been subjected to incredible experimental scrutiny over the last 40 years, and passed all tests with flying colours, wheras deBB is now beginning to consider how it can be extended to include the standard model. I consider that a deficit of four decades' worth of research amounts to a substantial body of science that orthodox methods have yielded and deBB has not.
I DO also claim that such attempts as there are to formulate a bohmian QFT have less utility than their orthodox counterparts. You have the particular opportunity to convince me that this statement is false, by providing links to published works in which deBB theory reproduces predictions made by orthodox QFT and experimentally verified. This, and in my present opinion only this, constitutes sufficient evidence to refute that claim. Once again, I suggest you start with reference to calculation of those quantities suggested by reilly.
I guess you guys really missed me
<< I should have said: 'Most of the presentation of technical material within the paper was concerned with explaining the predictions of nonrelativistic QM in terms of particles subject to dynamics described by the guidance equation', but it would have made a clumsy parenthesis. >>
Nah, you could have just said "that paper deals with explaining the predictions of both nonrelativistic and relativistic pilot wave QM and QFT". A word of advice - it's
always better to be a little more elaborate and accurate, than to be inaccurate and concise.
<< The conclusion I drew is
not that deBB is incompatible with QFT as you claim (perhaps ironically, given the nature of this accusation) but that as a predictive tool deBB in its present state has substantially less power and utility than the orthodox methods employed by the majority of researchers. >>
But you have no logical basis for establishing that conclusion if you don't even know what the relativistic and field theoretic extensions of deBB look like in the first place. It sounds like you're making the assumption that just because the majority uses one method in favor of another, the majoritarian method must be superior. That doesn't follow at all. Let me give you a counterexample: the majority of QCD theorists for a long time used the equal-time formulation, in favor of Dirac's light-front formulation. But the latter is well known to those who are familiar with it to have many more drastically superior computational advantages over the standard equal-time formulation of QCD. Unfortunately, the light-front QCD formulation was only developed much later in the 80s and 90s, and so it has taken much more time to catch on. Similarly also for Parisi-Wu stochastic quantization.
<< My tone has self-evidently become more terse throughout these posts, in direct response to your abrasive manner and evasion of several clear requests. >>
You should be more careful with accusations. I am not evading anybody.
<< I AM claiming that as a predictive tool, deBB is substantially less useful than the paradigm within which most researchers operate. I base this claim in particular on the fact that the Standard Model has been subjected to incredible experimental scrutiny over the last 40 years, and passed all tests with flying colours >>
The success of the SM doesn't have anything to do with deBB beyond putting a lower bound on the potential successfulness of the latter. You still don't seem to understand the connection between the standard and deBB versions of QT.
<< wheras deBB is now beginning to consider how it can be extended to include the standard model. I consider that a deficit of four decades' worth of research amounts to a substantial body of science that orthodox methods have yielded and deBB has not. >>
You're also making a number of false assumptions (which many newbies do), in particular, about the amount of intellectual effort that has gone into deBB theory versus standard QM. You don't seem to realize that for several decades, the theory was forgotten about (even by Bohm after his nervous breakdown and bout with depression) until the 70's when like 3 of his students revived it. And it was only until the 80's that there were more than 10 people working on the subject and clearing up the issues of its nonrelativistic and relativistic differences from standard QM. And only in the 90's and 2000's has there been more active research on quantum equilibrium issues and field theoretic extensions. Also keep in mind that the funding for this kind of research is very hard to come by for political and bureaucratic reasons. In other words, even though the theory has been around for 50+ years, the amount of intellectual manpower devoted to it has been miniscule compared to even 1 year's worth of intellectual mapower devoted to standard QM today. So it is not at all a fair comparison to make.
Now with regard to what Reilly asked and my claims, I think you misunderstood the claims muppet. Reilly asked me
"
Can this alternate theory
allow us to
1. compute the electron's magnetic moment to 13 decimal places as is done with standard QED, 2. compute the pion-nucleon scattering S-matrices; 3. derive the Fermi-Thomas approximation, or equivalent thereof, used in atomic physics(heavy elements)4. can this approach bring anything new to the issue of quark containment?"
I answered in the affirmative. What this amounts to is the claim that there exist field theoretic versions of pilot wave theory that are
empirically equivalent to standard QED and QCD, and that one can always transcribe these calculations from the standard field theory to a pilot wave field theory, given this empirical equivalence. Also, the standard QFT and pilot wave QFT share much of the same mathematics, and much of the calculations in pilot wave theory actually go along the same lines as in the standard theory; the difference is that at the end of the day you use the wavefunctional to compute the guiding equation for the field variable (or particle) given by dPhi/dt = J/rho. So at the end of the day you see the physical process in terms of the trajectory of a field variable or particle. So none of this should come as any surprise either. Indeed for these reasons, my answers to Reilly are trivially true.
Whether anyone working on pilot wave theory has actually bothered to reproduce those specific calculations and publish them, I do not know - but that is irrelevant for the reasons above. In fact, it would be a waste of time to try and do that. It is already
necessary and sufficient to show that the pilot wave field theories are empirically equivalent to the standard field theories used for the above calculations, and that it is always possible to transcribe the calculations from the standard field theories to the corresponding pilot wave field theories. Will the pilot wave field theories
always provide a computational superior method? No, not necessarily, for the same reason that, for example, the path integral approach does not always provide the most computationally superior method for any QFT calculation. No single approach to field theory will necessarily be the most computationally convenient across the board: but, I would claim that unlike the other approaches, the pilot wave field theories are the most conceptually and mathematically unambiguous insofar as supplying a theory of relativistic and field theoretic measurement processes. Without further adieu, here are
some of the most recent works on pilot wave field theories (from newest to oldest):
Field beables for quantum field theory, W. Struyve, to be published in Physics Reports (0707.3685 [quant-ph]).
http://arxiv.org/abs/0707.3685
A minimalist pilot-wave model for quantum electrodynamics, W. Struyve, H. Westman, Proc. Roy. Soc A 463, 3115-3129 (2007) (0707.3487 [quant-ph]).
http://arxiv.org/abs/0707.3487
A Dirac sea pilot-wave model for quantum field theory, S. Colin, W. Struyve, J. Phys. A: Math. Theor. 40, 7309-7341 (2007) (quant-ph/0701085).
http://arxiv.org/abs/quant-ph/0701085
A new pilot-wave model for quantum field theory, W. Struyve, H. Westman, in "Quantum Mechanics: Are there Quantum Jumps? and On the Present Status of Quantum Mechanics", eds. A. Bassi, D. Duerr, T. Weber and N. Zanghi, AIP Conference Proceedings 844, 321 (2006) (quant-ph/0602229).
http://arxiv.org/abs/quant-ph/0602229
For you Reilly, have a look at the first paper, and in particular, section 2.2, all of section 3, all of section 4, section 5, section 6, and section 7. That should give you all you need to get a feel for how these pilot wave field theories work and how they reproduce the predictions of standard QFT in relation to the questions you asked.
Hopefully you won't flake out on me.
. Just because someone isn't familiar with Jackson's EM text (not that I am not) doesn't have anything at all to do with their credibility or the validity of what they say. Furthermore, many schools like UCLA or even Stony Brook teach EM from different texts like Milton/Schwinger or Landau/Lifschitz, which has many things in it that Jackson doesn't have. Seriously, lay off all these argumentums ad authoritarium (a big-time logical fallacy by the way).
