All cosmological observations to date are consistent with adiabatic, Gaussian and nearly
scale invariant initial conditions. These findings provide strong evidence for a particular …

The stochastic signal detected by pulsar timing arrays (PTAs) has raised great interest in
understanding its physical origin. Assuming the signal is a cosmological gravitational-wave …

We identify a characteristic pattern in the scalar-induced stochastic gravitational wave
background from particle production during inflation. If particle production is sufficiently …

The past two decades have seen transformative advances in cosmology and string theory.
Observations of the cosmic microwave background have revealed strong evidence for …

Primordial non-Gaussianities from multi-field inflation are a leading target for cosmological
observations, because of the possible large correlations generated between long and short …

We study a model of inflation in which a scalar field χ is non-minimally coupled to
Starobinsky's R 2 gravity. After transforming it to the Einstein frame, a new scalar field, the …

All single-field inflationary models invoke varying degrees of tuning in order to account for
cosmological observations. Mechanisms that generate primordial black holes (PBHs) from …

Although cosmic microwave background and large scale structure probe the largest scales
of our Universe with ever-increasing precision, our knowledge about the smaller scales is …

We show that the contribution of the primordial trispectrum to the energy density of the scalar-
induced stochastic gravitational wave background cannot exceed the one from the scalar …

We report on a novel phenomenon of the resonance effect of primordial density
perturbations arisen from a sound speed parameter with an oscillatory behavior, which can …