The Rényi and Tsallis entropies are discussed as possible alternatives to the Bekenstein-Hawking area-law entropy. It is pointed out how replacing the entropy notion, but not the Hawking temperature and the thermodynamical ...

© 2020 The Authors In the context of a ghost free f(R,G) model, an extended matter bounce scenario is studied where the form of the scale factor is given by a(t)=(a0t2+1)n. The ghost free character of the model is ensured ...

In this work we shall address the ghost issue of F(R,G) gravity, which is known to be plagued with ghost degrees of freedom. These ghosts occur due to the presence of higher than two derivatives in the field equations, and ...

In this work we shall study the implications of a subclass of E-models cosmological attractors, namely of a-attractors, on hydrodynamically stable slowly rotating neutron stars. Specifically, we shall present the Jordan ...

© 2020 The Author(s). We investigated realistic neutron stars in axion R2 gravity. The coupling between curvature and axion field φ is assumed in the simple form ~R2φ. For the axion mass in the range ma ~ 10-11-10-10 eV ...

© 2020 American Physical Society. Some cosmological scenarios with bulk viscosity for the dark energy fluid are considered. Based on some considerations related to hydrodynamics, two different equations of state for dark ...