Abstract The Laser Interferometer Space Antenna (LISA) has two scientific objectives of
cosmological focus: to probe the expansion rate of the universe, and to understand …

We review the landscape of QCD axion models. Theoretical constructions that extend the
window for the axion mass and couplings beyond conventional regions are highlighted and …

A bstract In recent years, several pulsar timing array collaborations have reported first hints
for a stochastic gravitational wave background at nano-Hertz frequencies. Here we …

The first direct measurement of gravitational waves by the LIGO and Virgo collaborations
has opened up new avenues to explore our Universe. This white paper outlines the …

Cosmological gravitational particle production (CGPP) is the creation of particles in an
expanding universe due solely to their gravitational interaction. These particles can play an …

Gravitational waves (GWs) have a great potential to probe cosmology. We review early
universe sources that can lead to cosmological backgrounds of GWs. We begin by …

We investigate the sensitivity of the Laser Interferometer Space Antenna (LISA) to the
anisotropies of the Stochastic Gravitational Wave Background (SGWB). We first discuss the …

We review conceptual aspects of inflationary scenarios able to produce primordial black
holes by amplifying the size of curvature fluctuations to the level required to trigger black …

It is commonly assumed that the energy density of the Universe was dominated by radiation
between reheating after inflation and the onset of matter domination 54,000 years later …

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) …