Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present ...

We have quantized a flat cosmological model in the context of the metric f(R) models, using the causal Bohmian quantum theory. The equations are solved and then we have obtained how the quantum corrections influence the classical equations.

1. Laertes is about to stab Hamlet. Claudius, watching from the wings, desperately wants Laertes to stab Hamlet and has implanted a device in Laertes’ brain that, if activated, will force him to stab Hamlet. Claudius intends to activate the device if it appears that Laertes will change his mind at the last moment. Laertes, however, stabs Hamlet of his own accord and Claudius’s device is never a...

We construct spherically symmetric and static solutions in F ( R ) $F(R)$ gravity coupled with electromagnetic fields. The include new types of black holes electric magnetic charges. show that the higher-derivative terms make curvature singularity much softer than charged Einstein's general relativity. calculate some thermodynamical quantities obtained like entropy, Hawking radiation, quasi-loc...