• Thanks, Richard for this clarification.
    Of course, I think your analysis can also perfectly well apply to an ontic role for the quantum state.
    Under an epistemic view of the quantum state, then it seems to me that if one posits that measurements really do have definite outcomes, then an implicit hidden variable view must be lurking in the…[Read more]

  • This is an interesting situation: assessments of the bearing and validity of the FR proof greatly depend on what quantum theory itself is taken to be. For example, Editor has referred to two different forms of QT:
    (1) QT with collapse postulate — call it “QTCP”
    (2) QT without collapse postulate — call it “QTNCP”
    …and has noted, based on…[Read more]

  • I would just comment here that Brukner’s formulation of the measurement problem presupposes an epistemic interpretation of the quantum state relative to a particular observer. So his analysis and conclusions do not apply to cases in which the quantum state ontologically refers. In particular, he concludes that facts are necessarily…[Read more]

  • The Wigner’s Friend scenario was created to amplify the measurement problem as illustrated by Schrodinger’s Cat. We don’t encounter a Wigner’s Friend dilemma in the first place if we have a means of delineating, in physical terms, what constitutes ‘measurement’ (where that is described by von Neumann’s Process 1 non-unitary transition)…[Read more]

  • Dear Editor: Should I start a new topic to address the measurement problem, which is what is being illustrated by the Wigner’s Friends scenario? In particular, we don’t encounter a Wigner’s Friend dilemma in the first place if we have a means of delineating, in physical terms, what constitutes ‘measurement’ (where that is described by von…[Read more]

  • May I add as a relevant reference:
    Kastner, R. E. On the Status of the Measurement Problem: Recalling the Relativistic Transactional Interpretation
    International Journal of Quantum Foundations, 2017,
    Volume 4, Issue 1, pages 128-141

    • I would just note that RTI is not subject to the recent ‘no-go’ proofs since it does not assert that quantum states are universally applicable; rather it has a natural limiting criterion for the applicability of quantum states. It particular, neither the Geiger counter nor the cat nor Wigner nor his friend (understood as spacetime-locatable obj…[Read more]

  • The Transactional Interpretation involves advanced field states and is therefore considered a form of a ‘retrocausal’ interpretation, although in the relativistic development of TI (RTI), the advanced states (as well as the triggering retarded states) are complex objects and are sub-empirical (i.e., not spacetime processes). It is only the…[Read more]

  • It is not widely recognized that the Transactional Interpretation (TI) is a collapse theory; however, it is one that does not make ad hoc changes to the Schrodinger equation. Collapse is accounted for in TI by taking into account absorber response as a physical process (in the so-called ‘absorber theory’ of fields). Absorber response provides the…[Read more]

  • I would like to discuss the Relativistic Transactional Interpretation, specifically the explicit derivation of the Born Rule for radiative processes as presented in my recent paper with John Cramer (https://arxiv.org/abs/1711.04501).

    It appears clear that TI and RTI provide a physical account of measurement as well as a physical derivation of the Born Rule. Previous objections to TI (such as that of Maudlin) have been unambiguously resolved and/or nullified (e.g., https://arxiv.org/abs/1610.04609). Thus, TI is still perfectly viable and provides long-sought solutions to pressing problems in quantum theory regarding the need for a physically grounded definition of ‘measurement’ and the source of the Born Rule (as well as a solution to the consistency problems for QFT as reflected in Haag’s theorem, http://www.ijqf.org/archives/2004). Curiously, however, TI is still not generally recognized as among the ‘mainstream’ approaches. I look forward to discussing with other IJQF members why that might be. Is it the apparent “action at a distance” of the direct-action theory that is off-putting? Is it because both Wheeler and Feynman abandoned their theory (though Wheeler was later advocating it again in 2003)? Comments welcome.

  • R. E. Kastner, John G. Cramer  3 Feb. 2018

    Abstract: The Transactional Interpretation offers a solution to the measurement problem by identifying specific physical conditions precipitating the non-unitary […]

  • I rebut some erroneous statements and attempt to clear up some misunderstandings in a recent set of critical remarks by Marchildon regarding the Relativistic Transactional Interpretation (RTI) in this Journal, showing that his negative conclusions regarding the transactional model are ill-founded.

    Paper link here: Reply to LM IJQF4

  • At the request of D. Kalamidas I am posting his proposal for FTL signaling which appears in Pramana here: http://rdcu.be/AZYC
    I think it cannot work because it requires a well-defined time order for spacelike separated events, in which the measurement outcomes are assumed to occur for the signaler prior to the recipient, contrary to relativity…[Read more]

  • Just an update that this paper has been accepted in this journal.

  • I recently posted on the arxiv a paper written with John G. Cramer, refuting claims that absorption is not well-defined in the transactional interpretation. Comments welcome. https://arxiv.org/abs/1711.04501
    It should be noted that TI is not in the class of theories termed ‘spontaneous collapse theories’ (even though it has spontaneous col…[Read more]

  • Reasons to consider the Relativistic Transactional Interpretation, which allows for collapse without changing the basic quantum theory (and remedies shortcomings in the original TI):

    On the Status of the Measurement Problem: Recalling the Relativistic Transactional Interpretation

  • ABSTRACT. In view of a resurgence of concern about the measurement problem, it is pointed out that the Relativistic Transactional Interpretation (RTI) remedies issues previously considered as drawbacks or refutations of the original TI. Specifically, once one takes into account relativistic processes that are not representable at the non-relativistic level (such as particle creation and annihilation, and virtual propagation), absorption is quantitatively defined in unambiguous physical terms. RTI therefore provides a well-defined terminus to what appears to be a necessary infinite regress concerning ‘absorption’ when only the non-relativistic level is considered. In addition, specifics of the relativistic transactional model demonstrate that the Maudlin ‘contingent absorber’ challenge to the original TI cannot even be mounted: basic features of established relativistic field theories (in particular, the asymmetry between field sources and the bosonic fields, and the fact that slow-moving bound states, such as atoms, are not offer waves) dictate that the ‘slow-moving offer wave’ required for the challenge scenario cannot exist. It is concluded that issues previously considered obstacles for TI are no longer legitimately viewed as such, and that reconsideration of the transactional picture is warranted in connection with solving the measurement problem.   PDF here: On the Status of the Measurement Problem Arxiv7

  • I hope that the editors of the mentioned volume will consider non-unitary collapse in the transactional picture. I realize that this is not considered a ‘mainstream’ approach, but there are ample peer-reviewed publications on it with no refutations that I’m aware of. A recent peer-reviewed publication on the advantages of collapse for…[Read more]

    • I should add that there has been an attempted refutation, but that was shown to be based on misunderstanding of the model (refs on request)

  • ABSTRACT. It is shown that violation of the Born Rule leads to a breakdown of the correspondence between the quantum electromagnetic field and its classical counterpart. Specifically, the relationship of the quantum coherent state to the  classical electromagnetic field turns out to imply that if the Born Rule were violated, this could result in apparent deviations from the energy conservation law applying to the field and its sources (Poynting’s Theorem). The result, which is fully general and independent of interpretations of quantum theory, suggests that the Born Rule is just as fundamental a law of Nature as are the field conservation laws.

    Born Rule Violation and Maxwell Eqs

    • This paper has been sent out for peer review.

    • I think this paper is not correct. Of course, if one tries to violate the Born rule using only the equations of orthodox quantum theory, then one will get spurious results like an apparent violation of energy conservation. However, it is quite obvious from Rod Sutherland’s retrocausal “weak measurement” completely relativistic Lagrangian formulation of Bohm’s pilot wave/beable theory with the additional post-quantum action-reaction terms between the pilot waves and the beables that the stress-energy current densities are conserved i.e. Tuv^;v = 0 where Tuv = Tuv(pilot wave) + Tuv(be able) + Tuv(pilot wave be able). Kastner’s paper only has, in effect the Tuv(pilot wave) term. There is no consistent way to violate the Born rule without the additional terms. That’s all Kastner has really shown in my opinion. Sutherland has posted his theory elsewhere on this forum.

    • The submitted paper shows that violation of the Born Rule leads to a breakdown of the correspondence between quantum and classical forms of the electromagnetic field. The paper does not argue that energy conservation is violated at the micro-level, so the arguments put forth here don’t refute anything in the paper. It is straightforward that deviation of the photon detection rates from that given by the Born Rule as applied to coherent states results in deviations from Maxwell’s equations. One can see that simply by looking at how, for violations of the Born Rule, the amplitude envelope of the field would stray from the form required for classical correspondence (see https://en.wikipedia.org/wiki/Coherent_states#/media/File:Coherent_state_wavepacket.jpg) . Evidently the commenter thinks that it would be possible to violate the Born Rule and still preserve the quantum/classical correspondence in a different theory. He is welcome to demonstrate how that would work (even though the referenced figure clearly shows that deviations from Born Rule detection rates spoils the amplitude envelope). In any case, that would not refute the submitted paper, because it is not the subject of the paper.

    • A referee report has been received.

    • Ruth misunderstands my claim. The Sutherland action-reaction post-quantum violation of the Born rule vanishes in the limit where the Glauber coherent state solutions apply to the real world. Therefore, her argument is logically inconsistent.

    • Referees agreed with arguments in this paper and it has been accepted. Indeed there is no inconsistency; if there is no Born Rule violation in the limit Dr. Sarfatti discusses, then there is also no ‘real world’ applicability of such Born Rule violations as he has previously argued. The paper simply shows that real world Born Rule violations lead to real world deviations from Maxwell’s equations. This is an elementary result that is not controversial.

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