The teleparallel equivalent of general relativity is an intriguing alternative formulation of general relativity. In this thesis, we examine theories of teleparallel gravity in detail, and explore their relation to a whole spectrum of alternative gravitational models, discussing their position within the hierarchy of Metric Affine Gravity models. Consideration of alternative gravity models is m...

We investigate f (R) theories of gravity within the Palatini approach and show how one can determine the expansion history, H(a), for an arbitrary choice of f (R). As an example, we consider cosmological constraints on such theories arising from the supernova type Ia, large scale structure formation and cosmic microwave background observations. We find that best fit to the data is a non-null le...

In modified theories of gravity including a critical acceleration scale a0, a critical length scale rM = (GM/a0) will naturally arise with the transition from the Newtonian to the dark matter mimicking regime occurring for systems larger than rM . This adds a second critical scale to gravity, in addition to the one introduced by the criterion v < c of the Schwarzschild radius, rS = 2GM/c. The d...

8:50am–9:40am Cliff Burgess (McMaster/Perimeter Institute) Effective field theories and modified gravity: A bad cop wrapped in a wet blanket standing in a cold shower 9:40-10:30 Norbert Wex (MPI, Bonn) Tests of gravity from radio pulsars 10:30-10:50 Coffee break 10:50-11:40 Pedro Ferreira (Oxford) Testing general relativity with cosmology 11:40-12:30 Nicolas Yunes (Montana State) Gravitational ...

We shall investigate the properties of a congruence of geodesics in the framework of Palatini f(R) theories. We shall evaluate the modified geodesic deviation equation and the Raychaudhuri’s equation and show that f(R) Palatini theories do not necessarily lead to attractive forces. Also we shall study energy condition for f(R) Palatini gravity via a perturbative analysis of the Raychaudhuri’s e...

In this study, a numerical examination of the significance of rotation and changeable gravitational field on the start of nanofluid convective movement in an anisotropic porous medium layer is shown. A model that accounts for the impact of Brownian diffusion and thermophoresis is used for nanofluid, while Darcy’s law is taken for the porous medium. The porous layer is subjected to uniform rotat...