On Jan 6, 2018, at 5:48 PM, Ruth Kastner <This email address is being protected from spambots. You need JavaScript enabled to view it. > wrote:
"I agree 100% with what Kent says here. People on this list will be familiar with my critiques of time-symmetric hidden variables approaches (e.g., https://arxiv.org/abs/1607.04196)."
RK: "I think it's appropriate to view these as only semi-classical accounts and that there is a need for a deeper understanding of the referent of the quantum formalism.”
JS: I would not use “semi-classical” as that already has a precise meaning as for example, quantizing the electron but using classical stochastic EM fields as in Jaynes SED etc. Sure the PQM Locally Retrocausal (LR) Destiny-History Weak Measurement (WM) Wave Action <—> Particle Reaction (A <—> R) Lagrangian formalism of Ray Sutherland is able I CLAIM to explain many important experimentally accessible phenomena INCLUDING LIFE AND CONSCIOUSNESS (QUALIA) I claim within its “domain of validity” (Bohm). I do not deny the possibility of a deeper theory in which PQM is emergent, but for all practical purposes (such as conscious nano-electronic SENTIENT AI, low power warp drive as seen in the “tic tac” USS Nimitz incident off San Diego 2004 and other things like room temperature superconductors with topological “braid” computing etc - I HAVE NO NEED OF RUTH AND OTHER’S CONJECTURES. I could be wrong, but experiments will decide.
In particular, I agree wholeheartedly that: "classical relativistic spacetime is emergent, higher-order, approximate, and based on something deeper.."which is just what I have been exploring in my work on the transactional interpretation (in which quantum systems represent possibilities). E.g.: http://www.ijqf.org/archives/4398 and my CUP book (2012): www.cambridge.org/9781108407212and see also with Kauffman & Epperson https://arxiv.org/abs/1709.03595
1) It is non-Bohmian i.e. waves only, no “particles” (& no classical gauge field “beables”)
2) It makes the error (actually Feynman made that error) that Aharonov’s advanced destiny wave (Cramer’s confirmation wave) is the complex conjugate of Aharonov’s retarded history wave (Cramer’s offer wave).
Rod Sutherland corrects both of these obvious, to us Bohmians (1952 version), errors of conceptualization of how the universe, independent of puny human-level consciousness (how arrogant - have they learned nothing since Copernicus?) is really constructed as a post-quantum mechanism beyond the classical clockwork (retarded causation “algorithmic” approximation).
Hi Everyone --
Best to all,Ruth
From: Kent Peacock <This email address is being protected from spambots. You need JavaScript enabled to view it. >
Sent: Saturday, January 6, 2018 5:06 PM
To: JACK SARFATTI;This email address is being protected from spambots. You need JavaScript enabled to view it.
I think I should add my current ten cents worth to this discussion, if I may.
First, let me correct the short history that I gave in my email to Demetrios. In fact, the first paper (that I am aware of) to express doubts about the no-signalling arguments was by P. J. Bussey, Phys Lett A, 123(1): 1-3, 1987. He stated that the no-signalling arguments are "ad hoc." I was not made aware of Bussey's paper until (I think) the late 1990s. My thesis of 1991, and my short piece in PRL in 1992, explicitly raised the claim that these arguments assume what they should prove. And then, as I mentioned, J.B. Kennedy published an exceptionally clear and general critique of the no-signalling arguments in Philosophy of Science, 62: 543-560, 1995. The paper by Mittelstaedt is in Annalen der Physik 7, 710-715, 1998; and a paper by Steve Weinstein in Synthese, 148, 381-399, 2006, also expresses similar doubts about the no-signalling arguments. Fred Muller has also raised questions about the orthdox view of locality in QM. If anyone out there is aware of other authors who have critiqued "peaceful coexistence" or the no-signalling arguments, I would be very grateful to hear about them.
If P.J. Bussey is reading this, my apologies for forgetting to mention your paper when I wrote to Demetrios. (I did cite it in my "Nitpicking Distinction" paper, attached. I wrote this paper about ten years ago and I would now express some parts of it a bit differently; but I still stand by the basic points of the paper.)
Now, what can one say about the locally retrocausal interpretation of quantum mechanics? I do not share Jack's confidence that this view solves the puzzle of nonlocality.
I admit that the suggestion of Costa de Beauregard is attractive: all points in the universe are linked by forward and backward light cones; the interval along the light cones is null, and therefore one could say that in terms of proper time along light cones (remember, proper time is path-dependent) all events in relativistic universes are in this sense coincident. Does this mean that there is no need to explain quantum correlations by means of spacelike interactions? I do not think that anyone has yet demonstrated that we can entirely eliminate "spooky action" by means of local retrocausality, and I think it is exceedingly unlikely that this approach can hope to succeed.
Now, I do not deny that QM allows for, and indeed probably demands, backwards-in-time amplitudes (or propagators). Aharonov and coworkers have been exploring this in several of their papers. But as every reader of this thread will know, an amplitude is not a classical trajectory. There are in general amplitudes for classically inconsistent system evolutions; these will in general interfere and will influence the predicted probabilities, correlations, cross-sections, etc., in measurable ways. So if there are amplitudes from the future, they do not imply that the future "exists" in a definite classical state; I suspect that this alone is sufficient to rule out the block universe view.
Re. Price and Wharton: IMHO, their conjecture that one can eliminate entanglement by any sort of reinterpretation of Minkowski geometry is exceedingly implausible. One must understand how basic entanglement really is to quantum mechanics. Formally, it is a consequence of the superposition principle: every linear combination of allowed states is an allowed state. Therefore, in order to describe many-particle states, one must use the tensor product space, which is precisely the space of all linear combinations of the states of the individual particles. For basic algebraic reasons such a state must have a higher multiplicity than the sum of the individual particle states, which means that there have to be irreducible cross-terms both in the tensor product state itself and (I would argue, though this remains to be demonstrated in all generality) in operators acting over the tensor product space, including the Hamiltonian. That is the formal basis of nonlocality. To entirely banish entanglement one would essentially have to do impose massive and I think arbitrary restrictions on the superposition principle, some superselection rule on steroids that would have to be so artfully crafted as to block every prediction that is embarrassing to relativity, but which would preserve all of the other well-confirmed predictions of QM that depend upon superposition. (Heck of a lot of those.) Good luck with that.
Rod Sutherland's work is well developed, and I have a lot of respect for his mathematical ability. (He and J.R. Shepanski published what is probably the first correct superluminal Lorentz-like transformations, though I do not entirely agree with their interpretation of their important results. See their paper in Phys Rev D, 33, 2896-2902, 1986.) I still have not studied his recent papers in detail, so what I'll say here is tentative: I think that what he has done is produce a semi-classical approximation, not a fundamental theory that can underwrite quantum mechanics. I am ready to be corrected on this point, of course. But that's what it looks like to me so far.
I think that Sutherland is right to draw attention to Bohm's version of QM. But the really interesting thing about the Bohm interpretation of QM is the quantum potential, a non-local energy field. Bohm showed that it is implicit in the basic mathematical structure of QM. Yes, particles must react back on the potential field, a consideration that Bohm himself shied away from. But the really important point is that the energy of quantum systems has a non-local component. The question of whether "particles can be particles" is a red herring, entirely irrelevant. Of course(IMHO) particles can't be particles! I think that was settled a long time ago. So Bohm's theory itself, insofar as it uses continuous trajectories, is semi-classical---it is a semi-classical theory that takes explicit account of the nonlocality of quantum dynamics. The fact that Bohm treats action as a continuous quantity, and differentiates it as if it were a continuous, differentiable function, is sufficient to show that the theory is semi-classical.
There are several tricky questions of interpretation around the principle of relativity. For instance, many authors (including Sutherland) think that the mere existence of a superluminal interaction would define a "preferred frame" that would violate the equivalence of all frames. In my view this is a very elementary error, but this email is long enough as it is. See my https://sites.uclouvain.be/latosensu/index.php/latosensu/article/view/33.
Jack, what you said many years ago in Spacetime and Beyond has to be essentially correct: classical relativistic spacetime is emergent, higher-order, approximate, and based on something deeper that we only partially understand.
Okay, there is a lot more to be said, but I had best stop here.
Kent
Lagrangian Description for Particle Interpretations of Quantum Mechanics -- Entangled Many-Particle Case
A Lagrangian formulation is constructed for particle interpretations of quantum mechanics, a well-known example of such an interpretation being the Bohm model. The advantages of such a description are that the equations for particle motion, field evolution and conservation laws can all be deduced from a single Lagrangian density expression. The formalism presented is Lorentz invariant. This paper follows on from a previous one which was limited to the single-particle case. The present paper treats the more general case of many particles in an entangled state. It is found that describing more than one particle while maintaining a relativistic description requires the specification of final boundary conditions as well as the usual initial ones, with the experimenter's controllable choice of the final conditions thereby exerting a backwards-in-time influence. This retrocausality then allows an important theoretical step forward to be made, namely that it becomes possible to dispense with the usual, many-dimensional description in configuration space and instead revert to a description in spacetime using separate, single-particle wavefunctions.
Now, I do not deny that QM allows for, and indeed probably demands, backwards-in-time amplitudes (or propagators). Aharonov and coworkers have been exploring this in several of their papers. But as every reader of this thread will know, an amplitude is not a classical trajectory. There are in general amplitudes for classically inconsistent system evolutions; these will in general interfere and will influence the predicted probabilities, correlations, cross-sections, etc., in measurable ways.
Kent, I think you make a logical error here. This is explained very well in Mike Towler’s Cambridge Lectures on Bohm Pilot wave theory.
3) Bohm’s pilot wave theory does not require classical trajectories of the actual classical level particles (or of the EM gauge field configurations).
Sticking to particles for now, the actual trajectories deviate from the classical ones because of the action of the quantum potential Q. Indeed, Sutherland gives a particle equation of motion in addition to the Hamilton-Jacobi equation. I will give the details in another message to follow.
4) The Feynman amplitudes and Feynman diagrams apply ONLY to the WAVES not the PARTICLES.
In the little box of conventional QFT the many “particle" histories are simply gradient streamlines of the spread-out QUBIT waves - not the actual NON-CLASSICAL trajectory of the actual particle. There are no PARTICLES in conventional QFT which pure Bohr picture WAVES ONLY NEED APPLY.
Non-Bohmians get hopelessly muddled here (e.g. Mike Nauenberg’s objections) confusing the wave momentum operator P = (h/i)Grad with the classical particle momentum p. In general, in the PQM regime beyond QM
p - P =/= 0
5) Feynman’s path integral over all paths using the classical Lagrangian e^iL(c)/hbar works in Bohm theory almost the same as in orthodox QM.
6) However, if one uses the QUANTUM corrected Lagrangian L(Q) in e^iL(Q)/hbar then the integral is over the SINGLE ACTUAL NON-CLASSICAL PARTICLE TRAJECTORY! See Michael Towler “Return of the Pilot Waves"
Search Results
[PDF]The return of pilot waves - Theory of Condensed Matter - University of ...
The return of pilot waves. Or, why Bohr, Heisenberg, Pauli, Born, Schrödinger, Oppenheimer, Feynman,. Wheeler, von Neumann and Einstein were all wrong about quantum mechanics. Cambridge University Physical Society, 21st October 2009. Mike Towler. TCM Group, Cavendish Laboratory, University of Cambridge.
So if there are amplitudes from the future, they do not imply that the future "exists" in a definite classical state; I suspect that this alone is sufficient to rule out the block universe view.
Entangled Bell state prepared at source in past event E(S). Von Neumann IRREVERSIBLE strong-projective measurements are made in future at events E(A) & E(B).
As shown by Aephraim Steinberg http://advances.sciencemag.org/content/2/2/e1501466.full weak measurements reveal the trajectories of the Feynman functional path integral in this total experimental arrangement (stream lines of the waves). In the quantum limit (for massive particle for now not photons) a single particle will follow one of those stream lines with a likelihood given by the Born probability rule. Not so in the pumped PQM regime. That is another story. Meantime:
Weak measurement allows one to empirically determine a set of average trajectories for an ensemble of quantum particles. However, when two particles are entangled, the trajectories of the first particle can depend nonlocally on the position of the second particle. Moreover, the theory describing these trajectories, called Bohmian mechanics, predicts trajectories that were at first deemed “surreal” when the second particle is used to probe the position of the first particle. We entangle two photons and determine a set of Bohmian trajectories for one of them using weak measurements and postselection. We show that the trajectories seem surreal only if one ignores their manifest nonlocality.
There is no problem with Block Universe - the LR statement says that quantum information flows from E(A) to E(S).
You never have to say that E(A) exists at same time as E(S) for example for there to be a block universe.
In fact, that is clearly wrong logically. All one needs is the recognition of QM INFORMATION CHANNELS connecting the events.
The Costa de Beauregard zig-zag is.
E(A) —> E(S) —> E(B) + E(B) —> E(S) —> E(A) coherent superposition in a globally self-consistent time loop.
The same thing happens in Cramer’s TI with the error (Fred Wolf made same error in Star Wave Book).
Confirmation Wave = Complex Conjugate of Offer Wave
However, in Aharonov Sutherland zig-zag
Destiny Wave =/= Complex Conjugate of History Wave
Slow down. What you say is mathematically correct, but PHYSICALLY you need to make a distinction between GLOBAL ENTANGLEMENT and LOCAL ENTANGLEMENT.
Example 1 of LOCAL ENTANGLEMENT having nothing to do with Costa de Beauregard zig-zag
Electron in hydrogen atom in an oscillating classical EM field.
The perturbed state will be LOCALLY ENTANGLED sum of Orbitals x Spin Eigenfunctions x complex number coefficients
Example 2 of GLOBAL ENTANGLEMENT requiring zig-zag to not conflict with special relativity (neglect gravity for now).
Electrons A and B on two separated hydrogen atoms
Sum over Orbital (A)Orbital(B) spin(A) spin (B)
The zig-zag deals only with the orbital degrees of freedom (centered relative to the proton nucleus) not the spin degrees of freedom.
That the waves have no particle sources is essential for the UNITARITY (conservation of Born probability) hence for no entanglement signaling needed by Susskind for his solution of the black hole information loss problem.
PQM is a NON-UNITARY extension of QM in same way the GR is a curved spacetime extension of flat spacetime SR - in both cases the same root cause ACTION-REACTION - no UNMOVABLE MOVER!
But the really important point is that the energy of quantum systems has a non-local component.
Again, I claim with Rod, that any NONLOCALITY in SPACE-TIME can be handled by the zig-zag in the Aharonov sense of weak measurements with independent destiny and history waves not the Cramer TI sense in which he only has ONE independent wave.