We review applications of string theory to cosmology, from primordial times to the present-
day accelerated expansion. Starting with a brief overview of cosmology and string …

Primordial black holes (PBHs) generated by gravitational collapse of large primordial
overdensities can be a fraction of the observed dark matter. In this paper, we introduce a …

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

We propose a new model-independent mechanism for producing primordial black holes
from a period of multi-field inflation. This requires an enhancement of primordial fluctuations …

A bstract We show that a scalar excited state with large occupation numbers during inflation
leads to an enhancement of tensor modes and a characteristic pattern of order-one …

We argue that field trajectories, which lead to cosmic acceleration and feature rapid turns
near the boundary of the moduli space, are in the Swampland. We obtain this result by …

Several pulsar timing array (PTA) collaborations recently announced the first detection of a
stochastic gravitational wave (GW) background, leaving open the question of its source. We …

Stochastic inflation is an effective theory describing the super-Hubble, coarse-grained,
scalar fields driving inflation, by a set of Langevin equations. We previously highlighted the …

We study rapid-turn trajectories in a class of two-field cosmological models, whose scalar
manifold is the Poincaré disk. Background solutions in multi-field inflation, with field-space …

Strongly non-geodesic, or rapidly turning trajectories in multifield inflation have attracted
much interest recently from both theoretical and phenomenological perspectives. Most …