Relatividade geral com acoplamentos dependentes de escala e dimensões extras: consequências astrofísicas e cosmológicas

Abstract

General relativity extensions seek to resolve observational conflicts or implement new principles keeping the general relativity as a limiting case. Here we consider two classes of extended gravitaty: one in which the constants of general relativity G and Λ are promoted to scale-dependent quantities with direct impact for astrophysics and cosmology; the other deals with effective models for gravity in dimension higher than four, which have special impact for high energy physics, having direct consequences for primordial cosmology. Here we deal with their theoretical development, their observational limits, and possible observational signatures. In particular, the case of constants with scale dependence, we consider tests in the context of the solar system, in which we use the PPN formalism of Will and Nordtvedt, and in cosmology, in which we derive and evaluate the effective gravitational constant, the gravitational slip, fσ8 and other observables. For the second case, we deal with the scalar to tensor ratio and spectral index. With these results, we have obtained limits for both the models studied and opened up possibilities for future developments.