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 Transactional Interpretation (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. 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 the Transactional Interpretation are no longer legitimately viewed as such, and that reconsideration of the model is warranted in connection with solving the measurement problem.

Unitary-Only Quantum Theory Cannot Consistently Describe the Use of Itself: On the Frauchiger–Renner Paradox

“…Under RTI, the time of collapse is well-defined to within the uncertainty principle, which is an appropriate constraint on the precision of any such prediction (Kastner and Cramer 2018). RTI also yields a natural criterion for the micro/macro transition zone that is consistent with the fact that we never see flagrantly macroscopic superpositions (Kastner 2018).…”

The Weirdness Theorem and the Origin of Quantum Paradoxes

“…5 All these interpretations "do not view the quantum state as an intrinsic property of an individual system and they do not believe that a deeper reality is required to make sense of quantum theory" [12, p. 72]. Opposite to this tradition stand -ontic views such as the many world interpretation [13,14], hidden variable theories like Bohmian mechanics [15,16], collapse theories [17][18][19][20], or the transactional interpretations [21][22][23][24], the common trait being that quantum states are regared as descriptions of physical systems. 4 Notice that, in our perspective, the non-boolean structure is a consequence of algorithmic rationality as it follows from 'the weirdness theorem': the non-boolean structure arising from the non-standard evaluation functionals.…”

“…As a start, let us consider the case of classical probability. In CPT, under the reasonable assumption that since agents are expressing beliefs about physical systems, the underlying notion of dependence/independence should be compatible with that of a generative model, 23 structural judgements of independence/dependence are expressed via products: given factorised gambles…”

“…We do not aim to review all literature on hidden variable models. Clearly, it would be interesting to place our work within the ' -ontic/ -epistemic' interpretation of QT[12,92,93] agreeing with the Born's rule but not preserving the structure of functional dependencies in QT 23. There are other definitions of dependence/independence, such as epistemic irrelevance[53], that are not compatible with a notion of generative model.…”

Unitary Interactions Do Not Yield Outcomes: Attempting to Model “Wigner’s Friend”

“…RTI contains quantitatively well-defined physical non-unitarity that does not involve any ad hoc change to quantum theory, and is empirically equivalent at the level of the Born probabilities to standard unitary-only quantum theory. While it is not the purpose of this paper to advocate any particular alternative formulation of quantum theory, the interested reader may consult Kastner (2018), (2020a) and ( 2021) for some details.…”