Relational Quantum Mechanics and the Determinacy Problem

Federico Laudisa

Cristian Mariani

Abstract Of the many ways of getting at the core of the weirdnesses in quantum mechanics, there’s one which traces back to Schrödinger’s seminal 1935 paper, and has to do with the apparent fuzzy nature of the reality described by the formalism through the wavefunction $$\psi$$ ψ . This issue, which I will be calling the Determinacy Problem, is distinct from the standard measurement problem of quantum mechanics, despite Schrödinger himself ends up conflating the two. I will argue that the Determinacy Problem is an exquisitely philosophical problem, for as it is standard when facing any phenomenon which appears to have indeterminate or fuzzy characteristics, the solutions available are to either blame the deficiencies of our language, or our lack of knowledge, or to blame the world itself. These three attitudes can already be found in the literature on quantum mechanics, either explicitly or implicitly, and they appear to motivate three very distinct research programs: high-dimensional realism, primitive ontology, and quantum indeterminacy.

Carlo Rovelli C

Carlo Rovelli C

Nikolay Chavarga

The problem of measuring the energy of a quantum system, the process of emission of an electromagnetic field quantum, and their connection with the provisions of the Heisenberg uncertainty principle are considered. It is shown that the processes of measuring the energy of a quantum system and the time of transition between levels are performed not only simultaneously, but in a single act of measurement, and cannot be fulfilled in another way. This contradicts the physical ideas embedded in the uncertainty principle. As an alternative, the concept of "determinacy relations" is proposed.

Francisco Pipa

In this dissertation, I propose two frameworks to address some important scientific and philosophical issues with quantum theory (QT). First, I propose Environmental Determinacy-based Quantum Theory (EnDQT) and argue that contrary to the other well-known quantum theories, it has the great benefit of being a local, non-relational, and non-superdeterministic/non-retrocausal "interpretation" of quantum theory, or quantum theory (QT). EnDQT has the benefit of being conservative, not modifying the fundamental equations of QT, and, in principle, allowing arbitrary systems to be placed in a coherent superposition for an arbitrary amount of time. Also, EnDQT is able to give a local causal explanation of quantum correlations. Via EnDQT, I also argue that i) QT is local in the sense of not being in conflict with relativity but without the need to adopt a relationalist, a superdeterminist, or a retrocausal approach. I also argue that ii) the notorious measurement problem can be addressed without modifying the quantum formalism, adding hidden variables, or adopting relationalism. Second, I propose Generative Quantum Theory (GQT) as a new ontology for quantum theories and show how it can be implemented via GRW, the MWI and single-world relationalist views, Bohmian Mechanics, hybrid classical-quantum theories, and EnDQT. I also distinguish it from the most discussed ontologies for quantum theories, namely, wavefunction realism and primitive ontology, and argue that it has certain benefits that they lack without some of their costs, such as non-locality. Due to the overall benefits of GQT compared with these widely debated ontological frameworks, and given that GQT, contrary to these frameworks, considers the wavefunction more like a predictor and that quantum indeterminacy plays an important explanatory role, I will argue that iii) the wavefunction is more like a predictor for different possibilities rather than a law or a field in a multidimensional space, and that iv) quantum indeterminacy plays a key explanatory role instead of a derivative role in order to understand QT.