Variation of fundamental constants and white dwarfs

Abstract

Theories that attempt to unify the four fundamental interactions and alternative theories of gravity predict time and/or spatial variation of the fundamental constants of nature. Different versions of these theories predict different behaviours for these variations. As a consequence, experimental and observational bounds are an important tool to check the validity of such proposals. In this paper, we review constraints on the possible variation of the fundamental constants from astronomical observations and geophysical experiments designed to test the constancy of the fundamental constants of nature over different timescales. We also focus on the limits that can be obtained from white dwarfs, which can constrain the variation of the constants with the gravitational potential.

Machine learning meets the redshift evolution of the CMB temperature

“…They are not given by the theory and must be obtained experimentally. For a review on the variation of fundamental constants see [71]. Here we will probe the interesting case where the fine structure constant α = e 2 c is not invariant and we will express its relative variation as ∆α/α.…”

Bounds on the Horndeski gauge-gravity coupling

“…Here our aim is to use these observations to constrain the Horndeski non-minimal coupling parameter. These types of observations are also used to constrain other fundamental constants [35,36]. The typical values for the mass and radius of a white dwarf are…”

Constraining a possible time-variation of the speed of light along with the fine-structure constant using strong gravitational lensing and Type Ia supernovae observations

“…Besides, constraints on the variation in α in the early universe can be obtained from cosmic microwave background measurements [38][39][40][41][42] and primordial nucleosynthesis [43]. Moreover, other limits can be established from white dwarfs [44,45] and Galaxy clusters [28][29][30][31][32]; among many others.…”