Fundamental Constants in Physics and Their Time Variation

Abstract

In this Special Issue, we present a collection of fresh new articles, together with some review works, written by first-rate researchers in the field that offer the state-of-the-art on the subject of Fundamental Constants in Physics and Their Time Variation. There is no doubt that this is one of the hottest subjects in modern theoretical and experimental physics, with potential implications in all fundamental areas of physics research, such as particle physics, gravitation, astrophysics and cosmology.The history of this subject traces back mainly to Dirac's pioneering work in the thirties on the "large number hypothesis" [1] , from which a time evolution of the gravitational constant G was suggested, and later on the first discussions on new forms of the principle of equivalence emerged [2] and finally triggered the Jordan, Fierz and Brans-Dicke approach to gravity [3], in which General Relativity was extended to accommodate variations in G. It also triggered subsequent speculations by Gamow [4] and others on the possible variation of the fine structure constant.

Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies

“…Indeed, the possibility of doing these measurements deep into the matter era is particularly useful, since most other cosmological datasets (coming from type Ia supernovas, galaxy clustering, etc) are limited to lower redshifts. Recent reviews of the range of theoretical models so far explored are given in [1628] and in the comprehensive article by [1050]. Such a broad theoretical landscape necessarily results in a correspondingly broad range of expectations, all with important implications, but few with tight quantitative predictions.…”

Running Vacuum in the Universe: current phenomenological status

“…It can also provide an explanation for the possible (slow) time-evolution of the fundamental constants of Nature [21]. This is a field which probably holds many surprises in the future [22]. The natural impact from the RVM on this issue occurs thanks to the cosmological exchange of energy between vacuum, matter and the possible interplay with the Newtonian coupling G. Because µ ∼ H in Eq.…”

“…The incoming new era devoted to testing the micro and macro connection has just started. Most likely it will hint at the missing link between the physics of the very small and the physics of the very large [22], i.e. the (long soughtfor) overarching interconnection of the subatomic quantum mechanical world with the large scale structure of the Universe -and, ultimately, perhaps, the clue at solving the CC problem!…”