In the recent years, primordial black holes (PBHs) have emerged as one of the most
interesting and hotly debated topics in cosmology. Among other possibilities, PBHs could …

It has been a half-decade since the first direct detection of gravitational waves, which
signifies the coming of the era of the gravitational-wave astronomy and gravitational-wave …

We study whether the signal seen by pulsar timing arrays (PTAs) may originate from
gravitational waves (GWs) induced by large primordial perturbations. Such perturbations …

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 …

In this paper, we propose a novel mechanism in Bbb T 2-inflation to enhance the power
spectrum large enough to seed primordial black holes (PBHs) formation. To accomplish this …

The power-law parametrization for the energy density spectrum of gravitational wave (GW)
background is a useful tool to study its physics and origin. While scalar induced secondary …

We examine the possibility of Primordial Black Holes (PBHs) formation in single field models
of inflation. Using the adiabatic or wave function renormalization scheme in the short range …

We construct an analytically solvable simplified model that captures the essential features
for primordial black hole (PBH) production in most models of single-field inflation. The …

In canonical single-field inflation, the production of primordial black holes (PBH) requires a
transient violation of the slow-roll condition. The transient ultra slow-roll inflation is an …

Pulsar timing array collaborations have recently announced the discovery of a stochastic
gravitational wave (GW) background at nanohertz frequencies. We analyze the GW signals …