Power suppression from disparate mass scales in effective scalar field theories of inflation and quintessence

Abstract

A scalar potential coupled to other fields of large disparate masses will exhibit power suppression of the quantum loop corrections from these massive fields. Quintessence fields in the dark energy regime and inflaton fields during inflation often have a very large background field value. Thus any other field with its mass dependent on the quintessence/inflaton background field value through a moderate coupling will become very massive during the dark energy/inflation phase and its quantum corrections to the scalar effective potential will be suppressed. This concept is developed in this paper using the decoupling theorem. The problem then reduces to a quantitative question of the size of suppression effects within the parameter space of coupling constants, scalar field background value and renormalization scale. Some numerical examples are presented both for inflation and quintessence, but the approach is general and can be applied to any scalar field effective potential. The consequences to dark energy of the decoupling effect developed here is that the quintessence field need not just be an incredibly weakly interacting field, often included as an add-on to generate dark energy and having no other purpose. Instead, this quintessence field could play a central role in the particle physics dynamics at early times and then the other fields simply decouple from it at late times before the onset of the dark energy phase. For inflation a consequence is coupling of the inflaton to other heavy fields can be much larger.