Polymer inflation

TL;DR

This paper explores how polymer quantization of a scalar field influences early universe inflation, revealing a natural emergence of inflationary phases and the possibility of achieving sufficient inflation from sub-Planckian initial conditions.

Contribution

It demonstrates that polymer quantization leads to a generic inflationary phase and allows for significant slow-roll inflation from sub-Planckian initial data, offering new insights into quantum gravity effects on cosmology.

Findings

Identification of a polymer inflation phase almost exactly de Sitter

Polymer corrections modify slow-roll inflation formalism

Inflation can arise from sub-Planckian initial conditions

Abstract

We consider the semi-classical dynamics of a free massive scalar field in a homogeneous and isotropic cosmological spacetime. The scalar field is quantized using the polymer quantization method assuming that it is described by a gaussian coherent state. For quadratic potentials, the semi-classical equations of motion yield a universe that has an early "polymer inflation" phase which is generic and almost exactly de Sitter, followed by a epoch of slow-roll inflation. We compute polymer corrections to the slow roll formalism, and discuss the probability of inflation in this model using a physical Hamiltonian arising from time gauge fixing. We also show how in this model, it is possible to obtain a significant amount of slow-roll inflation from sub-Planckain initial data, hence circumventing some of the criticisms of standard scenarios. These results show the extent to which a quantum gravity motivated quantization method affects early universe dynamics.