Metric-scalar gravity with torsion and the measurability of the non-minimal coupling

TL;DR

This paper examines how non-minimal torsion-scalar couplings affect the Newtonian potential and finds that, for reasonable parameters, the resulting corrections are very small, questioning their measurability.

Contribution

It introduces a semi-classical analysis of the gravitational Darwin term with non-minimal torsion-scalar couplings, highlighting their minimal impact on observable effects.

Findings

Correction to Newtonian potential is very small for reasonable couplings.

Redefinition of the gravitational Darwin term due to torsion-scalar couplings.

Measurability of non-minimal couplings is limited by small effects.

Abstract

The "measurability" of the non-minimal coupling is discussed by considering the correction to the Newtonian static potential in the semi-classical approach. The coefficient of the "gravitational Darwin term" (GDT) gets redefined by the non-minimal torsion-scalar couplings. Based on a similar analysis of the GDT in the effective field theory approach to non-minimal scalar we conclude that for reasonable values of the couplings the correction is very small.