Observable physical modes of modified gravity

Electron-Cyclotron-Maser Observable Modes

We investigated wave amplification through the Electron-Cyclotron-Masermechanism. We calculated absorption and emission coefficients without any approximations, also taking into account absorption by the ambient thermal plasma. A power-law energy distribution for the fast electrons was used, as is indicated by X-ray and microwave observations. We developed a model for the saturation length and ...

Modes of log gravity

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. The physical modes of a recently proposed D-dimensional ''critical gravity'', linearized about its anti-de Sitter v...

Modified gravity and cosmology

Viscosity in Modified Gravity

A bulk viscosity is introduced in the formalism of modified gravity. It is shown that, based on a natural scaling law for the viscosity, a simple solution can be found for quantities such as the Hubble parameter and the energy density. These solutions may incorporate a viscosity-induced Big Rip singularity. By introducing a phase transition in the cosmic fluid, the future singularity can nevert...

Observational Tests of Modified Gravity

Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the Universe. Modified gravity theories have richer observational consequences for large scale structures than conventional dark energy models, in that different observables are not described by a single growth factor even in the linear regime. We examine the relationships betw...