Towards a Common Origin of Quantum Mechanics and Spacetime

Garnet N. Ord

The modern concept of spacetime usually emerges from the consideration of moving clocks on the assumption that world-lines are continuous. In this paper we start with the assumption that natural clocks are digital and that events are discrete. By taking different continuum limits we show that the phase of non-relativistic quantum mechanics and the odd metric of spacetime both emerge from the consideration of discrete clocks in relative motion. From this perspective, the continuum limit that manifests itself in 'spacetime' is an infinite mass limit. The continuum limit that gives rise to the Schrödinger equation retains a finite mass as a beat frequency superimposed on the 'Zitterbewegung' at the Compton frequency. We illustrate this in a simple model in which a Poisson process drives a relativistic clock that gives rise to a Feynman path integral, where the phase is a manifestation of the twin paradox. The example shows that the non-Euclidean character of spacetime and the wave-particle duality of quantum mechanics share a common origin. They both emerge from the necessity that clocks age at rates that are path dependent.

James B. Hartle

Vesselin Petkov

Eizo Nakaza

Conventional relativity places four-dimensional spacetime connected by Lorentz transformations, and fourdimensional spacetime curved by gravity, at the foundation of physical spacetime, whereas quantum mechanics places Hilbert space at the foundation of state description. As long as these two structures are simultaneously treated as fundamental realities, relativistic quantum theory and quantum gravity must begin with the problem of how a dynamically curved spacetime is to be quantized and made consistent with Hilbert-space states. Nakaza New Relativity Theory (NNRT) changes this very point of departure. NNRT takes universal time and universal three-dimensional space as physical spacetime and connects the real motions of all inertial systems by the Galilean Transformation (GT), while relocating the Lorentz transformation, time dilation, length contraction, and the gravitational metric to the observational and measurement layer obtained through electromagnetic phase. The successful mathematics and experimental values of conventional relativity are therefore retained, but the ontology in which curved and deformable four-dimensional spacetime is the unique physical spacetime is not retained. This paper uses NNRT as a new entry into quantum mechanics and repositions Hilbert space not as physical space, but as a mathematical representation space that preserves states, phases, probabilities, and correlations. Using the atomic clock as a concrete example, the paper further presents a continuous observational chain in which quantum levels generate a frequency scale and the resulting phase signal is compared between systems through relative motion and gravitational fields. Accordingly, the conventional entry point—how to quantize a physically real curved four-dimensional spacetime and incorporate it into Hilbert space—loses its premise within NNRT, and quantum theory and relativity are reconstructed as distinct representational and observational structures arising from a common universal physical spacetime. Schrödinger’s cat, EPR/Bell correlations, time dilation, length contraction, the twin problem, and the reification of the gravitational metric can then be organized as manifestations of a common ontological operation: identifying a mathematical representation with physical reality itself. The significance of this paper is therefore not to add another interpretation alongside conventional relativity, but to absorb its successful mathematics into the observational layer of NNRT and, by turning the ontological point of departure, to provide a new formulation of foundational problems that includes quantum mechanics.

Roger Boudet

Meir Hemmo, Orly Shenker

n their contribution to this book, McQueen and Vaidman argue that common sense requires that explanations in physics be not only causal1 but also local. Their main claim is that the Many Worlds Interpretation (MWI) of quantum mechanics (originally due to Everett) provides local explanations of the outcomes of experiments that in other interpretations of quantum mechanics seem to require (some sort of) nonlocality. Particles in the MWI leave traces both in the world where they exist but also in other worlds in which they do not exist. So the explanation is said to be local because spacetime splits together with the particles so that there is no influence at space-like separation within a world, but the causal influence literally travels across ‘parallel’ worlds. This seems to stretch the concept of locality beyond common sense, if not beyond breaking point, even if one understands causation weakly in terms of counterfactual dependence rather than by straightforward physical interaction.