Emergence of classical time from a universal wavefunction

P. Cameron

José Luis Gaona-Reyes, Lucía Menéndez-Pidal, Mir Faizal +1 more

A bstract Assuming that Quantum Mechanics is universal and that it can be applied over all scales, then the Universe is allowed to be in a quantum superposition of states, where each of them can correspond to a different space-time geometry. How can one then describe the emergence of the classical, well-defined geometry that we observe? Considering that the decoherence-driven quantum-to-classical transition relies on external physical entities, this process cannot account for the emergence of the classical behaviour of the Universe. Here, we show how models of spontaneous collapse of the wavefunction can offer a viable mechanism for explaining such an emergence. We apply it to a simple General Relativity dynamical model for gravity and a perfect fluid. We show that, by starting from a general quantum superposition of different geometries, the collapse dynamics leads to a single geometry, thus providing a possible mechanism for the quantum-to-classical transition of the Universe. Similarly, when applying our dynamics to the physically-equivalent Parametrised Unimodular gravity model, we obtain a collapse on the basis of the cosmological constant, where eventually one precise value is selected, thus providing also a viable explanation for the cosmological constant problem. Our formalism can be easily applied to other quantum cosmological models where we can choose a well-defined clock variable.

Sung-Sik Lee

Laurn Larson, Laurn Larson

Spacetime is not a fundamental arena but a representational interface that becomes valid only when a quantum state's internal relational structure satisfies specific conditions. This work synthesizes established results from quantum foundations, decoherence theory, and emergent spacetime research into a coherent ontology identifying when a wavefunction "licenses" a spacetime description. Three structural conditions must be jointly satisfied: (1) entanglement is sufficiently structured to support connected geometry; (2) entanglement is not so dense as to erase locality through volume-law scrambling; and (3) decoherence suppresses phase relationships enough to produce WKB-stable classical histories. A fourth structural condition: the Higgs field's vacuum expectation value, sets the classical mass spectrum and stabilizes decoherence. When all conditions hold, a subsystem is forced into a classical mode of representation characterized by locality, geometry, causal order, and sequential time. The Big Bang is reframed as the relational event at which these conditions were first satisfied, rather than a temporal origin. The rendering model is then extended to examine cosmological parameters as interface requirements, classical end-time scenarios as failures of the interface (not the substrate), and the metaphysical implications of a universe whose deepest ontology is non-geometric, nonlocal, and non-temporal. Drawing on philosophical traditions from Plato to Bergson alongside modern quantum gravity, the paper concludes that reality is correlation: spacetime is the classical world's shadow of a deeper relational whole, and the wavefunction is the universe.

Bernhard Baumgartner

Ibarrola Echeverría, Iker

This paper develops the operational and phenomenological structure of the Universal Correlational Lattice (UCL), a theoretical framework in which physical laws emerge from a fundamental network of correlational relations rather than from predefined spacetime geometry or wavefunction-based postulates. The UCL is formulated as a correlational substrate composed of sites connected by universal kernels that encode relational structure, internal evolution, and effective dynamics. Within this framework, spacetime, quantum fields, and classical observables are not assumed a priori, but arise as emergent, coarse-grained descriptions of deeper correlational processes. A central focus of this work is the clarification of how the theory operates operationally, i.e. how physical predictions, observables, and effective parameters are extracted from the correlational lattice without invoking traditional quantum-mechanical axioms such as fundamental wavefunctions, intrinsic probabilistic postulates, or instantaneous collapse. Probability appears instead as an emergent, contextual measure associated with partial access to the correlational network and with effective coarse-graining, rather than as a fundamental ingredient of the theory. The paper also develops the phenomenological layer of the UCL, showing how effective quantities—such as masses, coupling strengths, correlation lengths, decoherence scales, and metric-like structures—arise from the properties of the underlying kernels. These effective quantities reproduce familiar physical behavior in appropriate limits, while remaining compatible with a fundamentally deterministic and relational substrate. Special attention is given to: The role of internal times and their evolution as one-parameter flows within correlational sites. The emergence of effective temporal ordering without assuming a global external time. The interpretation of uncertainty, decoherence, and measurement as emergent phenomena linked to incomplete correlational resolution. The distinction between operational predictions and ontological commitments within the framework. This work positions the UCL as a unifying structural framework capable of reproducing known phenomenology while offering a conceptually coherent alternative to standard quantum-mechanical and spacetime-based foundations. The emphasis is placed on clarity of interpretation, operational consistency, and direct connection to measurable effective quantities.