The Equivalence Principle and the Constants of Nature

TL;DR

This paper reviews the reasons behind the specific values of nature's constants, discusses their potential dynamical nature, and emphasizes the importance of testing the Equivalence Principle to detect possible violations.

Contribution

It highlights the connection between the values of fundamental constants, their possible dynamical origin, and the necessity for improved Equivalence Principle tests.

Findings

Coupling constants may have a dynamical origin.

Potential violations of the Equivalence Principle could be observable.

Improved tests are needed to explore these violations.

Abstract

We briefly review the various contexts within which one might address the issue of ``why'' the dimensionless constants of Nature have the particular values that they are observed to have. Both the general historical trend, in physics, of replacing a-priori-given, absolute structures by dynamical entities, and anthropic considerations, suggest that coupling ``constants'' have a dynamical nature. This hints at the existence of observable violations of the Equivalence Principle at some level, and motivates the need for improved tests of the Equivalence Principle.