We explore whether nonstandard dark sector physics might be required to solve the existing
cosmological tensions. The properties we consider in combination are (a) an interaction …

Primordial black holes (PBHs) can generically form in inflationary setups through the
collapse of enhanced cosmological perturbations, providing us access to the early Universe …

Baryon acoustic oscillations (BAO) involve measuring the spatial distribution of galaxies to
determine the growth rate of cosmic structures. We derive constraints on cosmological …

In this work we shall present models of F (R) gravity which realize in a unified way the
inflationary era along with a post-inflationary early dark energy era, with the late-time dark …

In view of growing interest in long range scalar forces in the early universe to generate
primordial black holes, we study in detail the general relativistic formulation of a Fermi gas …

A unification of dark matter and dark energy based on a dynamical spacetime theory is
suggested. By introducing a dynamical spacetime vector field χ μ as a Lagrange multiplier …

We study a cosmological model based on the canonical Hamiltonian transformation theory.
Using a linear-quadratic approach for the free gravitational De Donder–Weyl …

Degenerate scalar-tensor theories of gravity extend general relativity by a single degree of
freedom, despite their equations of motion being higher than second order. In some cases …

The massless Dirac equation is studied in curved space-time on the (2+ 1)-dimensional
graphene sheet in time-dependent geometries. Emergent pseudogauge fields are found …

In this paper, we challenge some inflationary models with the recent new conjecture of the
swampland program, namely, further refining the de Sitter swampland conjecture. So far …