Mark Stuckey

  • I imagine local properties existing on p — B and q — A of Figure 3. So, on S — p and S — q you have holism and thereafter you have retrocausality. The two situations (holism and retrocausality) are, as you point out, distinct concerning local properties, but can be mixed (Figure 3) and transformed smoothly and continuously from one to another.…[Read more]

  • Let me start by saying I believe the main claim of your paper is correct and perfectly in keeping with the conventional understanding of holism. What I’m proposing is a change to the conventional understanding of holism based on the example in your paper. Sorry if you thought I was trying to refute your main claim. Attached is a candidate for t…[Read more]

  • Thanks for your reply, Peter. Please see attached a clarification of my point.

  • Hi Bob,

    Thanks for your input, it’s much appreciated and not the least bit “offensive.”
    We were concerned about just this sort of reaction, that’s why we tried the outline. Since that didn’t work, let me attach the slides for a short talk I had planned to give in Vaxjo last month (I instead gave the quantum Cheshire Cat talk posted in the “Other…[Read more]

  • Peter,
    Your understanding of SEPRB agrees with mine, so I’m hoping you’ve got it right 😉

    In the context of Evans’ paper in this forum, we might depict the holism of EPRB you describe as an undirected space-like link between its space-like separated outcomes (a la the undirected links in Evans’ Fig 4). One could attribute a direction to that li…[Read more]

  • The argument that retrocausality in a block universe violates faithfulness is essentially reflected by an anonymous referee in footnote 3 of our paper http://www.ijqf.org/wps/wp-content/uploads/2015/06/IJQF2015v1n3p2.pdf:

    “I do not see how anything truly ‘retrocausal,’ in a dynamical sense, can occur given global time-symmetric constraints on…[Read more]

  • Raul told me today that he doesn’t see any connection between Aharonov qCC and Denkmayr (alleged) qCC because Denkmayr doesn’t have a displaced pointer state. A weak values theorist (who asked not to be cited) agreed with our analysis saying “weakly enough” in Denkmayr should have read “linearly” because weak measurement requires linear…[Read more]

  • We update our Relational Blockworld (RBW) explanation of quantum physics and argue that it provides a realist psi-epistemic account of quantum mechanics as called for by Leifer. The paper is posted at http://www.ijqf.org/wps/wp-content/uploads/2015/03/Stuckey-et-al-2015-Revised-v2.pdf and will appear in the next issue of IJQF. The paper is 41 pp…[Read more]

  • I’ve had extensive contact with Raul Correa since last fall about his paper and ours. He failed to tell me that he got his paper accepted in New J Phys, but he apologized this week 🙂

    Correa et al explain how Aharonov’s proposed quantum Cheshire Cat (qCC) experiment with photons can be understood via interference. When they discuss the Denkmayr…[Read more]

  • In a July 2014 Nature Communications paper, Denkmayr et al. made the spectacular claim that in their interferometer experiment “the neutron and its spin are spatially separated.” They support their claim via their so-called “weak values” in this experiment, thus they claim to have successfully carried out the quantum Cheshire Cat experim…[Read more]

  • The hidden variables in RBW are the (graphical) spacetimesource element and the adynamical global constraint. We take a God’s eye (4D) view, so our hidden variables don’t “bring about events.” Per Geroch,

    “There is no dynamics within space-time itself: nothing ever moves therein; nothing happens; nothing changes. In particular, one does not…[Read more]

  • We’d be interested in how you classify RBW per your taxonomy, Dieter. Along those lines, Silberstein and I will try to explain the principle of superposition per RBW, as an example of your 3b (hidden variable, psi-epistemic) classification. [Sorry, we’re not sure how to do this for a general 3b case.]

    In our view, the fundamental ont…[Read more]

  • PTI certainly qualifies as “outside our comfort zone!” I did not mean to imply otherwise. [RBW is itself a form of direct action, so we took the liberty of referencing your IJQF paper for that in http://www.ijqf.org/archives/2087.%5D Have you yet extrapolated PTI’s implications for physics? I would like to see a PTI approach to quantum gravity, for example.

  • Mark Stuckey changed their profile picture 6 years, 7 months ago

  • I agree with Zeh, as I posted elsewhere http://www.ijqf.org/archives/2144, that “It is even more unfortunate that this confusion seems to be accompanied by a certain amount of prejudice (for or against some kinds of proposals).” I also agree “that we cannot decide between all these possibilities without any novel empirical evidence.” So, my…[Read more]

  • (*This is good stuff. It really helps to position what you’re doing against what others are doing.*)

    Thanks for taking the time to read and comment on the paper, as always Peter.

    (*I think it’s right to say that the difference between yourselves and Price & Wharton is largely a matter of stress. They stress the backwards causation, you s…[Read more]

  • Rovelli is correct that psi-ontology versus psi-epistemology is at the heart of the confusion about quantum theory. Psi-ontology has to deal with the measurement problem and collapse of the wave function, as Rovelli points out, while psi-epistemology leaves us asking, “Knowledge ABOUT WHAT?” Likewise, quantum information theory per Gri…[Read more]

  • We update our Relational Blockworld (RBW) explanation of quantum physics and argue that it provides a realist psi-epistemic account of quantum mechanics as called for by Leifer. RBW accomplishes this by employing discrete graphical amalgams of space, time and sources (“spacetimesource elements”) and an adynamical global constraint as ‘hidden variables’ that avoid the need for counterfactual definiteness in a realist account. Instead of an equation of motion governing time-evolved entities, the adynamical global constraint is used for computing the graphical transition amplitude whence a probability amplitude for our fundamental spacetimesource element. We begin with a largely conceptual and philosophical introduction to RBW’s most prominent features, i.e., adynamism, relationalism/contextualism, and the unmediated exchange of energy. This conceptual introduction includes a simple interferometer computation of the relative intensities found in a weak measurement that we compare with the authors’ computation per weak values. We use this to contrast our adynamical explanation of the experiment with the apparently dynamical, retro-time-evolved explanation of the authors’ Two State Vector Formalism. Next we use spacetimesource elements instead of paths in Dowker’s GHZ set-up to contrast RBW with Sorkin’s Many Histories account. We argue that rather than multiple paths per Many Histories, what is called for is no paths per RBW. The adynamical interpretation of these two quantum experiments, afforded by the global perspective, suggests that quantum mechanics might be underwritten adynamically. Thus, in the second part of the paper, we motivate an adynamical global constraint using coupled harmonic oscillators and then apply it to an analysis of the twin-slit experiment. This illustrates how the adynamical global constraint of our “modified lattice gauge theory” underwrites quantum field theory whence quantum mechanics. We conclude with a brief dismissal of the measurement problem and an RBW explanation of entanglement, environmental decoherence, quantum non-commutivity, quantum versus classical behavior, and the Born rule. 
    Here is the paper: Stuckey et al 2015 Revised. The paper has been revised per referee comments and Replies on the blog.

    • This paper has been sent out to peer review.

    • This is good stuff. It really help to position what you’re doing against what others are doing.

      I think it’s right to say that the difference between yourselves and Price & Wharton is largely a matter of stress. They stress the backwards causation, you stress the acausal constraints. But they have the acausal constraints too, and you have the backwards causation (construed in a sufficiently deflationary manner).

      A small point: on p.6 you suggest that any account that uses the statistical independence loophole is retrocausal. I don’t think that can be right, because you can at least envision a conspiratorial theory with only past-to-future causation (Bell’s “superdeterminism”). But what you say immediately after that sentence sounds right: global constraint models are retrocausal under a suitable analysis of causation.

      On the difference between your model and TSVF: I guess I don’t see the TSVF as particularly dynamical. Granted, you’ve got these two vectors that evolve forwards and backwards in time. I don’t know how DFBV describe them, but it looks to me like they’re a kind of heuristic — what’s real is the discontinuous photon trajectory (where the two vectors overlap). That is, you could construe DFBV and yourselves as proposing alternative methods of constructing one and the same thing. (Although I’m not exactly sure what the end result of your construction is — see below).

      On the specter of instrumentalism: What exactly is the ACGC a constraint on? Waves, particles, both? No — you say “neither”. You don’t mean “nothing”, right? In some places you say the source-sink energy transfer is unmediated, but then it does start to smell of instrumentalism — the constraint is just a constraint on the detector clicks. In other places you say the constraint is a constraint on a spacetimesource element — which looks like a spatiotemporal entity (or at least an entity that has a spatiotemporal aspect).

      (Incidentally, it’s not so clear that TSVF answers “waves” to the above question. They would certainly say “photons”, but it’s not clear what a photon is for them. It’s whatever is represented by the regions of overlap of the two waves. Maybe it’s a spacetimesource element!)

    • (*This is good stuff. It really helps to position what you’re doing against what others are doing.*)

      Thanks for taking the time to read and comment on the paper, as always Peter.

      (*I think it’s right to say that the difference between yourselves and Price & Wharton is largely a matter of stress. They stress the backwards causation, you stress the acausal constraints. But they have the acausal constraints too, and you have the backwards causation (construed in a sufficiently deflationary manner).*)

      This part of the paper is due in part to valuable input from Ken Wharton who explained that our use of future boundary conditions is a form of retrocausation. In fact, Price refers to the “global constraint” nature of his Helsinki model and Wharton’s L = 0 constraint is spatiotemporally global (“all at once” to use his term).

      (*A small point: on p.6 you suggest that any account that uses the statistical independence loophole is retrocausal. I don’t think that can be right, because you can at least envision a conspiratorial theory with only past-to-future causation (Bell’s “superdeterminism”). But what you say immediately after that sentence sounds right: global constraint models are retrocausal under a suitable analysis of causation.*)

      We agree and will make that more clear.

      (*On the difference between your model and TSVF: I guess I don’t see the TSVF as particularly dynamical. Granted, you’ve got these two vectors that evolve forwards and backwards in time. I don’t know how DFBV describe them, but it looks to me like they’re a kind of heuristic — what’s real is the discontinuous photon trajectory (where the two vectors overlap). That is, you could construe DFBV and yourselves as proposing alternative methods of constructing one and the same thing. (Although I’m not exactly sure what the end result of your construction is — see below).*)

      TSVF is dynamical as we defined it because TSVF adds a new dynamical mechanism to the block universe whereas we do not – we use an adynamical global constraint (AGC) that requires no new dynamics, heuristic or otherwise. If TSVF embraced your deflationary interpretation of their account “as proposing alternative methods of constructing one and the same thing [an adynamical global constraint],” we would certainly welcome that. In that case, we would suggest to DFBV they should consider abandoning the redundant explanatory aspect of the two-vector formalism and rather state that their backward and forward-time-evolved wavefunctions (or whatever they are) constitute a spatiotemporally global constraint. Perhaps Lev Vaidman will offer input, in which case we will revise the paper accordingly. In any case one doesn’t need both a new dynamical mechanism and an AGC, and in the paper we argue why the latter ought to be fundamental. Given your take on TSVF it sounds like you agree.

      (*On the specter of instrumentalism: What exactly is the AGC a constraint on? Waves, particles, both? No — you say “neither”. You don’t mean “nothing”, right? In some places you say the source-sink energy transfer is unmediated, but then it does start to smell of instrumentalism — the constraint is just a constraint on the detector clicks. In other places you say the constraint is a constraint on a spacetimesource element — which looks like a spatiotemporal entity (or at least an entity that has a spatiotemporal aspect).*)

      The AGC constrains the probability amplitude for our beables, i.e., spacetimesource elements, which are spatiotemporal 4D ontological entities. Hopefully, we have clarified the role of the AGC in the non-mathematical outline of the twin-slit analysis below. The spatiotemporal distribution of detector clicks is in accord with the distribution of spacetimesource elements per the probability amplitude obtained in accord with the AGC. Again, a spacetimesource element isn’t *in* spacetime, it’s *of* spacetime, even while a distribution of detector clicks is viewed in the spacetime context of the experimental equipment and process from initiation to termination. This is RBW’s version of OSR in a block universe.

      (*Incidentally, it’s not so clear that TSVF answers “waves” to the above question. They would certainly say “photons”, but it’s not clear what a photon is for them. It’s whatever is represented by the regions of overlap of the two waves. Maybe it’s a spacetimesource element!*)

      We should probably allow someone in the TSVF program to answer that. Again, if they will provide us with input, we will gladly revise our paper accordingly.

      (*I still can’t follow the details of the derivation of two-slit interference. Time to go back to school…*)

      You are the exemplar target audience, so if you can’t follow the section on twin-slit, then we need to outline the formalism here. The computation is in three parts and the goal is to produce a non-relativistic, source-to-source QFT probability amplitude ψ for the spacetimesource element in the twin-slit experiment per our “modified lattice gauge theory” (MLGT). First, we use the transition amplitude for the Klein Gordon (KG) action in the non-relativistic limit to produce a propagator D(x – x’) between point sources from the generating function W(J). Next, we relate D(x – x’) to the probability amplitude ψ of the Schrödinger Equation (SE), even though the SE is homogeneous (has no source terms). Lastly, we discretize the transition amplitude of the non-relativistic KG action with source terms and use the adynamical global constraint (AGC) to find our MLGT counterpart to W(J), and thus ψ, for the spacetimesource element. A modification to the discretization process is required by the AGC since there is an undifferenced (non-relational) term ψ* in the non-relativistic KG action. The AGC also tells us which eigenmode of our difference matrix is relevant. Essentially, the second and third parts justify and explain our use of the propagator D(x – x’) between point sources in non-relativistic QFT in computing the probability amplitude ψ for the spacetimesource element of the twin-slit experiment. [We should have limited the plots for the example to the physical range –π to π, as well.] This non-mathematical summary suffices to convey the content of that section conceptually, so we should have provided it in the paper.

      Hopefully, the referees will give us a chance to make these corrections 🙂

    • A referee report has been received.