Causal Description of Measurement in Quantum Mechanics

David Thomas Pegg

Rodolfo Gambini, Rafael A. Porto

We have recently introduced a realistic, covariant, interpretation for the reduction process in relativistic quantum mechanics. The basic problem for a covariant description is the dependence of the states on the frame within which collapse takes place. A suitable use of the causal structure of the devices involved in the measurement process allowed us to introduce a covariant notion for the collapse of quantum states. However, a fully consistent description in the relativistic domain requires the extension of the interpretation to quantum fields. The extension is far from straightforward. Besides the obvious difficulty of dealing with the infinite degrees of freedom of the field theory, one has to analyze the restrictions imposed by causality concerning the allowed operations in a measurement process. In this paper we address these issues. We shall show that, in the case of partial causally connected measurements, our description allows us to include a wider class of causal operations than the one resulting from the standard way for computing conditional probabilities. This alternative description could be experimentally tested. A verification of this proposal would give a stronger support to the realistic interpretations of the states in quantum mechanics. 1

Rodolfo Gambini, Rafael A Porto

We have recently introduced a realistic, covariant, interpretation for the reduction process in relativistic quantum mechanics. The basic problem for a covariant description is the dependence of the states on the frame within which collapse takes place. A suitable use of the causal structure of the devices involved in the measurement process allowed us to introduce a covariant notion for the collapse of quantum states. However, a fully consistent description in the relativistic domain requires the extension of the interpretation to quantum fields. The extension is far from straightforward. Besides the obvious difficulty of dealing with the infinite degrees of freedom of the field theory, one has to analyse the restrictions imposed by causality concerning the allowed operations in a measurement process. In this paper we address these issues. We shall show that, in the case of partial causally connected measurements, our description allows us to include a wider class of causal operations than the one resulting from the standard way of computing conditional probabilities. This alternative description could be experimentally tested. A verification of this proposal would give stronger support to the realistic interpretations of the states in quantum mechanics.

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Serkan Eksioglu

Kang, Tae Hyuk

Causal–Continuity Stabilization Theory (CCST): Thermodynamic Stability and Branch-Internal Descriptive Continuity in Everettian Dynamics. DOI: https://doi.org/10.17605/OSF.IO/D6JN7. Causal–Continuity Stabilization Theory (CCST) is an interpretive framework that addresses the persistence of macroscopic descriptive continuity within fully unitary Everettian quantum mechanics. Rather than invoking ontological selection, probabilistic collapse, or inter-branch transition, CCST reframes continuity as a stability property of a finite physical substrate subject to irreversible thermodynamic and dynamical constraints. The theory introduces Thermodynamic Strain as a path-dependent measure of cumulative irreversible burden required to maintain coherent macroscopic descriptive structure across decoherence and branching. CCST remains fully compatible with standard quantum mechanics and preserves the physical reality of all branches, while providing an explicit stability-based criterion for when continuous macroscopic description remains physically well posed.