Constraining theories of gravity by GINGER experiment

Abstract

The debate on gravity theories to extend or modify general relativity is very active today because of the issues related to ultraviolet and infrared behavior of Einstein’s theory. In the first case, we have to address the quantum gravity problem. In the latter, dark matter and dark energy, governing the large-scale structure and the cosmological evolution, seem to escape from any final fundamental theory and detection. The state of the art is that, up to now, no final theory, capable of explaining gravitational interaction at any scale, has been formulated. In this perspective, many research efforts are devoted to test theories of gravity by space-based experiments. Here, we propose straightforward tests by the GINGER experiment, which, being Earth based, requires little modeling of external perturbation, allowing a thorough analysis of the systematics, crucial for experiments where sensitivity breakthrough is required. Specifically, we want to show that it is possible to constrain parameters of gravity theories, like scalar–tensor or Horava–Lifshitz gravity, by considering their post-Newtonian limits matched with experimental data. In particular, we use the Lense–Thirring measurements provided by GINGER to find out relations among the parameters of theories and finally compare the results with those provided by LARES and Gravity Probe B satellites.

Renormalizability of Alternative Theories of Gravity: Differences between Power Counting and Entropy Argument

“…The presence of higher order terms yields several interesting aspects, as well as massive gravitational waves [26][27][28] or modifications of the Newtonian potential [29][30][31]. Other theories leading to higher than fourth-order field equations can be constructed by the general action:…”

“…With the purpose of studying the Bekenstein-Hawking entropy provided by f (G) = f 0 G k gravity, let us rewrite the spherically symmetric solution (31) as:…”

Renormalizability of alternative theories of gravity: differences between power counting and entropy argument

“…With the purpose to study the Bekenstein-Hawking entropy provided by f (G) = f 0 G k gravity, let us rewrite the spherically symmetric solution (31) as:…”

Linearized Field Equations and Extra Force in $f(R,{\bf T}^{(n)})$ Extended Gravity

“…In all cases, the variation of the extended action with respect to the metric tensor provides extra terms in the higher-order field equations, which can be recast as an effective energy-momentum tensor of the gravitational field. In this way, dark energy and dark matter can be mimicked by geometric contributions [34][35][36] and additional potentials arise in the weak field limit [37]. Moreover, from the one-loop effective action of GR, it turns out that renormalizability requires higher-order corrections to allow the UV divergences canceling out.…”