Transactional Interpretation

The most part of the debates on Quantum Mechanics (QM) interpretation come out from the remains of a classical language based upon waves and particles. Such problems can find a decisive clarification in Quantum Field Theory (QFT), where the concept of “classical object” is replaced by an interaction networks. On the other hand, it is simpler to discuss about non-locality in QM than in QFT. We propose here the concept of transaction as a connection between theQM and QFT language as (...) well as the possibility to introduce quantum non-locality ab initio.We also mention the cosmological consequence of a non-local archaic vacuum here defined. (shrink)

This paper takes up Huw Price׳s challenge to develop a retrocausal toy model of the Bell-EPR experiment. I develop three such models which show that a consistent, local, hidden-variables interpretation of the EPR experiment is indeed possible, and which give a feel for the kind of retrocausation involved. The first of the models also makes clear a problematic feature of retrocausation: it seems that we cannot interpret the hidden elements of reality in a retrocausal model as possessing determinate dispositions to (...) affect the outcome of experiments. This is a feature which Price has embraced, but Gordon Belot has argued that this feature renders retrocausal interpretations “unsuitable for formal development”, and the lack of such determinate dispositions threatens to undermine the motivation for hidden-variables interpretations in the first place. But Price and Belot are both too quick in their assessment. I show that determinate dispositions are indeed consistent with retrocausation. What is more, I show that the ontological economy allowed by retrocausation holds out the promise of a classical understanding of spin and polarization. (shrink)

The transactional interpretation of quantum mechanics, following the time-symmetric formulation of electrodynamics, uses retarded and advanced solutions of the Schrödinger equation and its complex conjugate to understand quantum phenomena by means of transactions. A transaction occurs between an emitter and a specific absorber when the emitter has received advanced waves from all possible absorbers. Advanced causation always raises the specter of paradoxes, and it must be addressed carefully. In particular, different devices involving contingent absorbers or various types of interaction-free measurements (...) have been proposed as threatening the original version of the transactional interpretation. These proposals will be analyzed by examining in each case the configuration of absorbers and, in the special case of the so-called quantum liar experiment, by carefully following the development of retarded and advanced waves through the Mach-Zehnder interferometer. We will show that there is no need to resort to the hierarchy of transactions that some have proposed, and will argue that the transactional interpretation is consistent with the block-universe picture of time. (shrink)

This thesis is a study of the notion of time in modern physics, consisting of two parts. Part I takes seriously the doctrine that modern physics should be treated as the primary guide to the nature of time. To this end, it offers an analysis of the various conceptions of time that emerge in the context of various physical theories and, furthermore, an analysis of the relation between these conceptions of time and the more orthodox philosophical views on the nature (...) of time. In Part II I explore the interpretation of nonrelativistic quantum mechanics in light of the suggestion that an overly Newtonian conception of time might be contributing to some of the difficulties that we face in interpreting the quantum mechanical formalism. In particular, I argue in favour of introducing backwards-in-time causal influences as part of an alternative conception of time that is consistent with the picture of reality that arises in the context of the quantum formalism. Moreover, I demonstrate that this conception of time can already be found in a particular formulation of classical mechanics. One might see that one of the central themes of Part II originates from a failure to heed properly the doctrine of Part I: study into the nature of time should be guided by modern physics and thus we should be careful not to insert a preconceived Newtonian conception of time unwittingly into our interpretation of the quantum mechanical formalism. Thus, whereas Part I is intended as a demonstration of methodology with respect to the study of time, Part II in a sense explores a confusion that can be seen as arising in the absence of this methodology. (shrink)

Beginning with a review the logically first stages in the project of Random Dynamics, hoping for all laws nature being emergent, we also review what can be considered a consequence of Random Dynamics, a model—by myself and Masao Ninomiya—, which in principle predicts the initial conditions in such a way as to minimize a certain functional of the history of the Universe through both past and future. This functional is indeed the imaginary part of the action, which exists (only) in (...) our model of complex action. The main point of the present is to suggest this complex action model to be also helpfull in solving some problems for quantum mechanics. Especially as our model almost makes it possible in principle to calculate the full history of the universe, it even makes it in principle calculable, which one among several measurement results in a quantum experiment will actually be realized!Our “complex action model” thus is a special case of superdeterminism—in Bells way—and does not have true causality, but rather even in some cases true backward causation. In fact we claim in our model that the SSC(Superconducting Supercollider) were stopped by the US Congress due to the backward causation from the big amounts of Higgs particles, which it would have produced, if it had been allowed to run. The noumenon (“das Ding an sich”) in our model is the Feyman path integrand or better some fundamental quantities determined from second order effects of the latter integrand. The quantum mechanics interpretation here is strongly similar to the much criticized “transactional interpretation” by John Cramer (Rev. Mod. Phys. 58:647–688, 1986), but we might respond to some of the criticism. (shrink)

This conference proceedings would be of interest to theoretical and experimental physicists in the areas of foundations of physics, nature of time, foundations of quantum mechanics, quantum measurement, quantum computation. Philosophers of science and physics. Retrocausation, the process whereby the future affects its past, is central to the modern movement to understand the fundamental physical nature of time. This conference volume presents the most recent theoretical and experimental results at the forefront of the nascent field of physical chronology.

Cramer's Transactional Interpretation (TI) is applied to the ``Quantum Liar Experiment'' (QLE). It is shown how some apparently paradoxical features can be explained naturally, albeit nonlocally (since TI is an explicitly nonlocal interpretation). At the same time, it is proposed that in order to preserve the elegance and economy of the interpretation, it may be necessary to consider offer and confirmation waves as propagating in a ``higher space'' of possibilities.

Table of Contents: Preface.- 1. Introduction; Mauricio Suárez.- PART I: PROBABILITIES.- 2. Probability and time symmetry in classical Markov processes; Guido Bacciagaluppi.- 3. Probability assignments and the principle of indifference: An examination of two eliminative strategies; Sorin Bangu.- 4. Why typicality does not explain the approach to equilibrium; Roman Frigg; PART II: CAUSES.- 5. From metaphysics to physics and back: The example of causation; Federico Laudisa.- 6. On explanation in retro-causal interpretations of quantum mechanics; Joseph Berkovitz.- 7. Causal completeness in (...) general probability theories; Balasz Gyenis, Miklós Rédei.- 8. Causal Markov, robustness and the quantum correlations; Mauricio Suárez, Iñaki San Pedro.- PART III: PROPENSITIES.- 9. Do dispositions and propensities have a role in the ontology of quantum mechanics? Some critical remarks; Mauro Dorato.- 10. Is the quantum world composed of propensitons?; Nicholas Maxwell.- 11. Derivative dispositions and multiple derivative levels; Ian Thompson. (shrink)

Tim Maudlin’s argument for the inconsistency of Cramer’s Transactional Interpretation (TI) of quantum theory has been considered in some detail by Joseph Berkovitz, who has provided a possible solution to this challenge at the cost of a significant empirical lacuna on the part of TI. The present paper proposes an alternative solution in which Maudlin’s charge of inconsistency is evaded but at no cost of empirical content on the part of TI. However, Maudlin’s argument is taken as ruling out Cramer’s (...) heuristic “pseudotime” explanation of the realization of one transaction out of many. (shrink)

Traditional causation posits that the past alone influences the present. In principle, however, the basic laws of physics permit the future an equal measure of influence: retrocausation. This symposium explores theoretical developments and experimental evidence for retrocausation. It is unique in stressing recent experiments in this exciting and potentially important new field.

The transactional interpretation of quantum mechanics is summarized and various points concerning the transactional interpretation and its relation to the Copenhagen interpretation are considered. Questions concerning mapping the transactional interpretation onto the Copenhagen interpretation, of advanced waves as solutions to proper wave equations, of collapse and the quantum formalism, and of the relation of quantum mechanical interpretations to experimental tests and results are discussed.

We consider several thought and practical experiments, and variations thereof, from which the existence can be inferred of retroactive effects on the assumptions of conservation of linear and angular momentum and of realism defined in a wide sense. Such conclusion is made less counterintuitive by research into the proper physical background of the relativistic length contraction of a moving arrow, viz. the fact that the universe is four-dimensional indeed. In one of the experiments considered, the evidence of retroactivity is more (...) striking and can more easily be actually demonstrated than was the case in earlier proofs. (shrink)

Copenhagen interpretation of quantum mechanics deals with these problems is reviewed. A new interpretation of the formalism of quantum mechanics, the transactional interpretation, is presented. The basic element of this interpretation is the transaction describing a quantum event as an exchange of advanced and retarded waves, as implied by the work of Wheeler and Feynman, Dirac, and others. The transactional interpretation is explicitly nonlocal and thereby consistent with recent tests of the Bell inequality, yet is relativistically invariant and fully causal. (...) A detailed comparison of the transactional and Copenhagen interpretations is made in the context of well-known quantum-mechanical Gedankenexperimenre and "paradoxes." The transactional interpretation permits quantum-mechanical wave functions to be interpreted as real waves physically present in space rather than as "mathematical representations of knowledge" as in the Copenhagen interpretation. The transactional interpretation is shown to provide insight into the complex character of the quantum-mechanical state vector and the mechanism associated with its "collapse." It also leads in a natural way to justification of the Heisenberg uncertainty principle and the Born probability law (P = ii iij*), basic elements of the Copenhagen interpretation. (shrink)

A modified Young double-slit experiment proposed by Wootters and Zurek is considered in which a system P of parallel plates covered with a photographic emulsion has been set up in the region where we would normally expect the central interference fringes. Because under certain conditions P makes it possible to conclude with much more than50% certainty through which of the two slits each particular photon passed, the relevant interference pattern becomes blurred. It is proved that this implies a retroactive effect (...) because the setup of P and the interaction of photons with P appear to influence the momentum transferred to the photons by the edges of the slits at an earlier stage of the experiment. (shrink)

We abandon as redundant the assumption that there exists something more in the physical world than action quanta, which constitute the atoms of the events of which the four-dimensional world consists. We derive metric, energy, matter, etc., from action and the structure formed by the quanta. In the microworld thequantization of space so introduced implies deviations from conventional metrics that make it possible in particular to explain nonlocality. The uncertainty relations, then, in conjunction with the action-based metric, appear to play (...) an essential role in making direct physical contact between emission and absorption events (i.e., retroactivity) possible, which concretely answers Bohr's conjecture that microprocesses constitute “wholes.” All of this appears to afford a realistic explanation of wave-particle “duality,” the EPR and other quantum paradoxes, the hidden variable problem, the “collapse” of wave packets, and the wave interference mechanism with the ¦ ϕ ¦2 rule. (shrink)

Examining the process of action at a distance, we arrive at the following conclusions: (a) The virtual photons and mesons transmitting Coulomb and nuclear forces, respectively, do not arise from “temporary violations of energy conservation,” but, on the contrary, exactly embody the potential energy corresponding to the relevant forceF that they transmit on their collision with the charged particles or nucleons via the formula Δp=FΔt. (b) In the case of an attractive force, the energy of these photons and mesons is (...) negative. The way this comes about is made clear by a more detailed investigation of Feynman's notion of “traveling backward in time.” (c) The action corresponding to, e.g., a virtual photon's appearance is exactly one quantumh, which fact is responsible for the unobservability of such photons. Some consequences of the revised conception of potential energy for, e.g., the tunnel and the Bohm-Aharonov effect are mentioned. (shrink)

The classical electrodynamics of point charges can be made finite by the introduction of effects that temporally precede their causes. The idea of retrocausality is also inherent in the Feynman propagators of quantum electrodynamics. The notion allows a new understanding of the violation of the Bell inequalities, and of the world view revealed by quantum mechanics. Published in The Universe, Visions and Perspectives, edited by N. Dadhich and A. Kembhavi, Kluwer Academic Publishers, 2000, pages 35-50.

This column is about experimental tests of the various interpretations of quantum mechanics. The question at issue is whether we can perform experiments that can show whether there is an "observer-created reality" as suggested by the Copenhagen Interpretation, or a peacock’s tail of rapidly branching alternate universes, as suggested by the Many-Worlds Interpretation, or forward-backward in time handshakes, as suggested by the Transactional Interpretation? Until recently, I would have said that this was an impossible task, but a new experiment has (...) changed my view, and I now believe that the Copenhagen and Many-Worlds Interpretations (at least as they are usually presented) have been falsified by experiment. (shrink)

The attractive feature of the Everett approach is its admirable spirit of approaching the quantum puzzle with a Zen-like "beginner’s mind" in order to try to envision what the pure formalism might be saying about quantum reality, even if that journey leads to a strange place. It is argued that the transactional interpretation of quantum mechanics (TI), appropriately interpreted, shares the same motivation and achieves much more, with far fewer conceptual perplexities, by taking into account heretofore overlooked features of the (...) quantum formalism itself (i.e. advanced states). In particular, TI does not need to talk about brain states, consciousness, or observers (rational or otherwise). In its possibilist variant (“PTI”), it shares the realist virtues of treating state vector branches as genuine dynamical entities, without having to explain how or why all of their associated outcomes actually happen (they don’t), how to account for a plenitude of counterpart observers in some coherent notion of trans-temporal identity of the bifurcating observers (observers don’t bifurcate in TI), nor how the certainty of all outcomes could be consistent with any coherent theory of probability, let alone the Born probability (the Born probability emerges naturally in TI). In short, TI is precisely the one-world interpretation Kent is looking for in his (2010). (shrink)