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High Energy Physics - Theory, hep-th,Astrophysics, Cosmology and Extragalactic Astrophysics, astro-ph.CO,General Relativity and Quantum Cosmology, gr-qc,High Energy Physics - Phenomenology, hep-ph
Abstract:
Many cosmological models assume or imply that the total size of the universe
is very large, perhaps even infinite. Here we argue instead that the universe
might be comparatively small, in fact not much larger than the currently
observed size. A concrete implementation of this idea is provided by the
no-boundary proposal, in combination with a plateau-shaped inflationary
potential. In this model, opposing effects of the weighting of the wave
function and of the criterion of allowability of the geometries conspire to
favour small universes. We point out that a small size of the universe also
fits well with swampland conjectures, and we comment on the relation with the
dark dimension scenario.
