Varying Constants, Gravitation and Cosmology

By Jean-Philippe Uzan. Living Reviews in Relativity, 2010

699 citations recorded by the source corpus.

Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/690b0a68729e936a9e4060c02db586662bd17b4f

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Citations in the corpus

Fundamental physics with the Square Kilometre Array (2018, background): “In summary, constraints on the variation of α at various red- shifts will significantly advance our basic understanding of nature, and might provide clues to new physics beyond the standard model (Uzan, 2011).”
General Relativity and Cosmology: Unsolved Questions and Future Directions (2016, neutral): “Solar System tests Metric coupling Quadrupolar shift of nuclear energy levels Isotropy [340–342] Lunar laser ranging and orbiting gyroscopes Universality of freefall [343] and structure of metric Space-borne clocks Gravitational redshift [344] Shift in perihelion of planets Structure of metric [345]”
Maximal freedom at minimum cost: linear large-scale structure in general modifications of gravity (2014, neutral): “refs [98, 99] and references therein) 1.”
Testing Relativistic Gravity with Radio Pulsars (2014, background): “r eld(s). More specically, in the T 1( 0; 0) theory of [57, 58], LLR tests for a variation of the gravitational constant that is given by G_ G = 2 1 + 0 1 + 2 0 0’_ 0 (68) (see equation (167) of [139]). For the eective gravitational constant between two strongly self-gravitating bodies (as measure”
Highly charged ions: Optical clocks and applications in fundamental physics (2018, background): “…studies of quasar spectra and observation of the H I 21 cm line, atomic clocks, the Oklo natural nuclear reactor, meteorite dating, stellar physics, cosmic microwave background, and big bang nucleosynthesis (see e.g. reviews (Chin et al., 2009; Kozlov and Levshakov, 2013; Uzan, 2011)).”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “A coupling to the electromagnetic sector leads to spacetime variations of Nature’s fundamental constants, which are constrained both by local atomic clock experiments and by astrophysical observations [1185].”