Exiting Inflation with a Smooth Scale Factor

Abstract

The expectation that the physical expansion of space occurs smoothly may be expressed mathematically as a requirement for continuity in the time derivative of the metric scale factor of the Friedmann-Robertson-Walker cosmology. We explore the consequences of imposing such a smoothness requirement, examining the forms of possible interpolating functions between the end of inflation and subsequent radiation- or matter-dominated eras, using a straightforward geometric model of the interpolating behavior. We quantify the magnitude of the cusp found in a direct transition from the end of slow roll inflation to the subsequent era, analyze the validity several smooth interpolator candidates, and investigate equation-of-state and thermodynamic constraints. We find an order-of-magnitude increase in the size of the universe at the end of the transition to a single-component radiation or matter era. We also evaluate the interpolating functions in terms of the standard theory of preheating and determine the effect on the number of bosons produced.

arXiv comment48 pages

References in corpus (11)

• Towards the Theory of Reheating After Inflation
• The Temperature of the Cosmic Microwave Background
• Inflation Dynamics and Reheating
• Reheating in Inflationary Cosmology: Theory and Applications
• Inflationary Cosmology
• Planck 2018 results. III. High Frequency Instrument data processing and frequency maps
• Recent Advances on Inflation
• Causality and the speed of sound
• Causal Representations of Neutron-Star Equations of State
• Particle physics models of inflation
• Accounting for the time evolution of the equation of state parameter during reheating