The anamorphic universe

TL;DR

The paper introduces 'anamorphic' cosmology, a novel approach combining contracting and expanding phases to explain the universe's smoothness, flatness, and density perturbations, avoiding issues of multiverse and measure problems.

Contribution

It presents the first framework of anamorphic cosmology, capable of generating nearly scale-invariant spectra with a single field and avoiding multiverse and measure problems.

Findings

Anamorphic models can produce nearly scale-invariant density perturbations.

They avoid multiverse and measure problems common in inflation.

Models incorporate a smoothing phase with unique contracting and expanding features.

Abstract

We introduce "anamorphic" cosmology, an approach for explaining the smoothness and flatness of the universe on large scales and the generation of a nearly scale-invariant spectrum of adiabatic density perturbations. The defining feature is a smoothing phase that acts like a contracting universe based on some Weyl frame-invariant criteria and an expanding universe based on other frame-invariant criteria. An advantage of the contracting aspects is that it is possible to avoid the multiverse and measure problems that arise in inflationary models. Unlike ekpyrotic models, anamorphic models can be constructed using only a single field and can generate a nearly scale-invariant spectrum of tensor perturbations. Anamorphic models also differ from pre-big bang and matter bounce models that do not explain the smoothness. We present some examples of cosmological models that incorporate an anamorphic smoothing phase.