# Ricci Subtraction for Cosmological Coleman-Weinberg Potentials

## TL;DR

This paper explores a novel subtraction method involving the Ricci scalar to address quantum corrections in inflation models, revealing that it causes rapid end to inflation due to an induced scalar degree of freedom.

## Contribution

It introduces and analyzes Ricci scalar subtraction as a new approach to mitigate Coleman-Weinberg corrections in inflationary potentials.

## Key findings

- Ricci scalar subtraction induces a new scalar degree of freedom.
- This approach causes inflation to end almost immediately.
- The method is not effective for controlling quantum corrections in inflation.

## Abstract

We reconsider the fine-tuning problem of scalar-driven inflation arising from the need to couple the inflaton to ordinary matter in order to make reheating efficient. Quantum fluctuations of this matter induce Coleman-Weinberg corrections to the inflaton potential, depending (for de Sitter background) in a complex way on the ratio of the inflaton to the Hubble parameter. These corrections are not Planck-suppressed and cannot be completely subtracted because they are not even local for a general geometry. A previous study showed that it is not satisfactory to subtract a local function of just the inflaton and the {\it initial} Hubble parameter. This paper examines the other allowed possibility of subtracting a local function of the inflaton and the Ricci scalar. The problem in this case is that the new, scalar degree of freedom induced by the subtraction causes inflation to end almost instantly.