Obtaining Precision Constraints on Modified Gravity with Helioseismology

TL;DR

This paper explores how helioseismology can be used to detect or constrain fifth forces predicted by certain dark energy theories, potentially improving existing bounds by over two orders of magnitude.

Contribution

It introduces helioseismology as a novel, precise method to constrain modified gravity theories, specifically applying it to DHOST models and demonstrating its high sensitivity.

Findings

Helioseismic data can significantly tighten constraints on fifth force strength.

Numerical computations of pulsation frequencies reveal observable effects of modified gravity.

Potential to improve constraints on dark energy theory functions by over 100 times.

Abstract

We propose helioseismology as a new, precision probe of fifth forces at astrophysical scales, and apply it on the most general scalar-tensor theories for dark energy, known as Degenerate Higher-Order Scalar-Tensor theories (DHOST). We explain how the effect of the fifth force on the solar interior leaves an observable imprint on the acoustic oscillations, and under certain assumptions we numerically compute the non-radial pulsation eigenfrequencies within modified gravity. We illustrate its constraining power by showing that helioseismic observations have the potential to improve constraints on the strength of the fifth force by more than $2$ orders of magnitude, as $-1.8 \cdot 10^{-3} \leq Y \leq 1.2 \cdot 10^{-3}$ (at $2\sigma$). This in turn would suggest constraints of similar order for the theory's free functions around a cosmological background ($\alpha_{\text{H}}, \beta_{1}$).