On Aug 14, 2016, at 8:50 AM, Stanley A. KLEIN <This email address is being protected from spambots. You need JavaScript enabled to view it. > wrote:
Many thanks Brian for that clarification that you meant "influence" rather than "cause" for FTL events. I think that should make everyone happy.
Positing any kind of FTL nonlocality that necessitates a preferred global frame of some kind is not only inconsistent with special relativity, but also with general relativity.
Rod Sutherland has shown us with a precise mathematical model why this is the case.
When faced with two alternative explanations of quantum entanglement (forget signaling at this juncture, I only mean orthodox quantum theory - no signaling) in which one violates classical relativity and the other one does not, obviously the latter is the better explanation.
"Objectively real" means independent of the choice of local frames of reference and how one freely chooses to paint coordinate on them. That is, there exist local-frame-invariants in terms of the mathematical formalism that is the map (in our consciousness if you like) of the real territory out there.
That is, good physics is ontological about the “territory."
The epistemology is secondary about the “map.”
“The map is not the territory.” A. Korzypski
Local objectively real retrocausality, admittedly in a block universe (the free will complaint is a bogus one in my opinion), clearly explains exactly why, barring no intermediate interactions, the space-time separation between future strong measurements of the individual particles in an entangled pair is irrelevant. This is explained by the Costa de Beauregard Zig Zag used by John Cramer in his TI. The distortion of the light cones by spacetime curvature does not change this fact.
Why retrocausality — and why free will?
The 'classic' motivation for retrocausal models in QM stems from Bell's Theorem, and the nonlocality it seems to entail. Nonlocality is often felt to be counterintuitive in itself, and the source of an unresolved tension between quantum theory and special relativity. As Bell himself described the implications of his famous result: “[I]t's a deep dilemma, and the resolution of it will not be trivial ... [T]he cheapest resolution is something like going back to relativity as it was before Einstein, when people like Lorentz and Poincaré thought that there was an aether — a preferred frame of reference — but that our measuring instruments were distorted by motion in such a way that we could not detect motion through the aether.''
As Bell was well aware, the dilemma can be avoided if the properties of quantum systems are allowed to depend on what happens to them in the future, as well as in the past. Like most researchers interested in these issues, however, Bell felt that the cure would be worse than the disease — he thought that this kind of “retrocausality” would conflict with free will, and with assumptions fundamental to the practice of science. (He said that when he tried to think about retrocausality, he “lapsed into fatalism”.)
If this objection to retrocausality in QM is well-founded, it raises interesting issues about the nature and origins of this "free will", that turns out to play such a surprising role in the foundations of physics. If the objection is not well-founded, then it is high time it is moved aside, so that the retrocausal approach can be given the attention it otherwise seems to deserve.
Moreover, there are other motivations for exploring retrocausal models in QM, some the focus of considerable current research. Examples include:
- The proposed retrocausal explanation of the results of 'weak measurements' by Aharonov, Vaidman and others.
- The relevance of retrocausality to the issue of the viability of an 'epistemic' interpretation of the quantum state, especially in the light of recent results such as the PBR Theorem.
- Recent work throwing new light on the relation between retrocausality in QM, on the one hand, and time-symmetry and other symmetries, on the other.
For these reasons, too, there is a pressing need for a better understanding of notions of free will and causality, and of their relevance to the retrocausal approach to the quantum world. This conference brought together many of the leading writers and researchers on these topics, to discuss these issues.
Search Results
[PDF]pdf - arXiv.org
by H Price - 2015 - Cited by 7 - Related articles
exploit some simple symmetries to show how Costa de Beauregard's zigzag needs to work, to explain the correlations at the core of Bell's. Theorem. As a bonus ...S Matrix, Feynman Zigzag and Einstein Correlation - INSPIRE-HEP
Jan 1, 1978 - ... preparations (Pflegor and Mandel). Costa De Beauregard, O. ... S Matrix, Feynman Zigzag and Einstein Correlation. O. Costa De Beauregard ...
S-matrix, Feynman zigzag and Einstein correlation - ADS
adsabs.harvard.edu/abs/1978PhLA...67..171D
Harvard University
by D Beauregard - 1978 - Cited by 19 - Related articles
S-matrix, Feynman zigzag and Einstein correlation. Authors: De Beauregard, O. Costa. Affiliation: AA(Institut Henri Poincaré, 75005 Paris, France). Publication:
You've visited this page 3 times. Last visit: 10/1/15
And thanks for pointing us to that Wikipedia site with the relevant section beingPhysical formulation of Lorentz boosts. It indeed reminded me that a boost in x,t is the same as a rotation in x,y. I would have preferred if the Wiki site had mentioned that it is standard practice to define the units of x and t to be such that c = 1. Then the boost and rotation equations are identical (other than that cosh vs cos due to the minus sign in the x^2 + y^2 + z^2 - t^2 metric). For those not familiar with relativity it is important to show how similar time is to space by showing how similar boosts are with rotations. For me choosing units with c=1 is critical for making that point. There is no need for x to be measured in meters and t to be measured in seconds.
Stan
On Sun, Aug 14, 2016 at 3:32 AM, Brian Josephson <This email address is being protected from spambots. You need JavaScript enabled to view it. > wrote:
I’d like to add to Stan’s comments. First of all, I accept his replacement of causality by influence.
“influence” + “signaling” = PQM
PQM is to QM as GR is to SR
In both cases it is the action-reaction that allows one to go from the special theory to the more general theory.
For SR —> GR it is the “two-way” action-reaction between classical spacetime geometry guv and classical stress-energy Tuv of source matter.
For QM —> PQM it is the “two-way” action-reaction between the weak measurement Aharonov advanced destiny <f|x> & retarded history <x|f> Bohm pilot waves with their commonly shared classical level “beables” that permits local retrocausal entanglement signaling in violation of the limits of the more special (restricted) orthodox quantum theory upon which all notions of quantum information, cryptography, dense coding, steering, purification, witnessing, error correction etc. etc. are based with a sense of false finality and false security.
Rod Sutherland has shown for many-particle entanglement that because of local objectively real retrocausality, we need not use many-dimensional configuration space.
The URL for this search is http://arxiv.org/find/all/1/all:+AND+Roderick+Sutherland/0/1/0/all/0/1
Showing results 1 through 6 (of 6 total) for all:(Roderick AND Sutherland)
- 1. arXiv:1509.07380 [pdf]
- 2. arXiv:1509.02442 [pdf]
- 3. arXiv:1509.00001 [pdf]
- 4. arXiv:1502.02058 [pdf]
- 5. arXiv:1411.3762 [pdf]
- 6. arXiv:quant-ph/0601095 [pdf]
My main point though relates to Jack’s suggestion that retrocausality its better than FTL mechanisms as a model as it preserves relativistic invariance. The problem with that though is that it refers to invariance under SR, not GR, so is just a special case, ignoring the influence of matter.
Ruth’s proposal, in line with Wheeler’s, is that space-time as we know it is constructed over the passage of time. And it is perfectly possible that the construction process is one that causes space-time to have the Lorentz invariance property, perhaps as a kind of byproduct, just as Maxwell’s equations have Lorentz invariance as a byproduct.
From the agential realism perspective, we would say that the creative process works on the basis of the possibility of generating particular phenomena, and in this spirit we could speculate that emergence of electromagnetism (as in ‘let there be light’) would be the driving mechanism for making space-time Lorentz invariant.
And symmetry could play a part in this. I recall Jeffrey Goldstone pointing out to me once that if you want to have a symmetry group for space time that includes boosts you have a choice of Galilean invariance or Lorentz invariance, depending on whether you want the boosts to commute or not (NB: you are unfamiliar with this use of the term boost, do a search on ‘boost relativity’).
Brian
On 14 Aug 2016, at 10:51, Stanley A. KLEIN <This email address is being protected from spambots. You need JavaScript enabled to view it. > wrote:
>
> Jack, I'd like to clarify that "mirage" exchange since I think the word "mirage" that you came up with is quite nice and cute.
>
> If look at the postings you will see that in the first email mentioning "mirage"
> Jack said: "Faster than light nonlocality is a mirage of local retrocausality"
> Brian reponded: "‘Retrocausality is a mirage of faster than light causality."
>
> The problem here is that last word: "causality". I think it should have been "influence".
>
> Then what I said was:
>
> Jack and Brian, many, many thanks for that "mirage" language. The way I had been saying it is that FTL (faster than light) makes more sense to me than BIT (backwards in time). That is, I like the von Neumann interpretation. But it still doesn't really make sense. So I'm beginning to like the mirage language:
>
> BIT is a mirage of FTL AND FTL is a mirage of BIT!!
>
> My point here is that we need to be careful about how we use the word "causality" in physics. If one googles causality in physics one finds the following:
>
> "In classical physics, an effect can not occur before its cause. In relativity theory, causality means that an effect can not occur from a cause which is not in the back (past) light cone of that event. Similarly, a cause can not have an effect outside its front (future) light cone."
>
> So Jack I hope that helps. One can use that de Beauregard/Aharanov/Cramer/ Kastner/(maybe Sutherland) backwards in time (BIT) mirage or one can use the von Neumann FTL mirage. None of them violate causality since they can't be used to send signals. They are merely mirages or interpretations. Were you the first to use the word "mirage" for those FTL influences?
> Stan
------
Brian D. Josephson
Emeritus Professor of Physics, University of Cambridge
Director, Mind–Matter Unification Project
Cavendish Laboratory, JJ Thomson Ave, Cambridge CB3 0HE, UK
WWW: http://www.tcm.phy.cam.ac.uk/~bdj10
Tel. +44(0)1223 37260/337254