Nuclear Limits on Non-Minimally Coupled Gravity

TL;DR

This paper uses nuclear physics constraints, specifically energy conditions in helium nuclei, to set extremely tight bounds on non-minimally coupled gravity theories, significantly improving previous limits.

Contribution

It introduces a novel method to constrain modified gravity theories using nuclear physics, achieving bounds over thirty orders of magnitude stronger than prior constraints.

Findings

Derived a new limit of |5| < 57 10^{-12} m^2 on the coupling parameter 5.

Showed nuclear physics can impose strong constraints on alternative gravity models.

Demonstrated the effectiveness of energy conditions in nuclear matter to test gravitational theories.

Abstract

We explore alternate theories of gravity where the gravitational term in the Lagrangian $\frac{R}{8\pi G}$ is replaced by a function $f_1(R)$ and the matter Lagrangian is multiplied by a function $f_2(R)$. We argue that nuclear physics can provide strong experimental constraints on such theories. In particular using energy conditions on the pressure in the $^4$He nucleus, for $f_1(R)=\frac{R}{8\pi G}$ and $f_2(R)=1+\lambda R$, we find a limit of $|\lambda| < 5\times 10^{-12}\, \hbox{m}^2$, more than thirty orders of magnitude stronger than the previous limit.