Constraining f(R) theories with the energy conditions

TL;DR

This paper introduces a method using energy conditions to constrain f(R) gravity theories by relating them to current cosmological parameters, providing practical limits on theory parameters.

Contribution

It presents a novel approach to constrain f(R) theories using the weak energy condition and current cosmological derivatives, including the snap parameter.

Findings

Method effectively limits f(R) theory parameters.

Constraints derived for specific f(R) models.

Error analysis demonstrates robustness of the approach.

Abstract

A new method to constrain gravitational theories depending on the Ricci scalar is presented. It is based on the weak energy condition and yields limits on the parameters of a given theory through the current values of the derivatives of the scale factor of the Friedmann-Robertson-Walker geometry. A further constraint depending on the current value of the snap is also given. Actual constraints (and the corresponding error propagation analysis) are calculated for two examples, which show that the method is useful in limiting the possible $f(R)$ theories.