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 …

We review recent trends in inflationary dynamics in the context of viable modified gravity
theories. After providing a general overview of the inflationary paradigm emphasizing on …

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 …

The Swampland program aims to distinguish effective theories which can be completed into
quantum gravity in the ultraviolet from those which cannot. This article forms an introduction …

We report on the implications for cosmic inflation of the 2018 release of the Planck cosmic
microwave background (CMB) anisotropy measurements. The results are fully consistent …

CMB-S4 Science Case, Reference Design, and Project Plan Page 1 CMB-S4 Science Case,
Reference Design, and Project Plan CMB-S4 Collaboration July 9, 2019 arXiv:1907.04473v1 …

Axions and other very light axion-like particles appear in many extensions of the Standard
Model, and are leading candidates to compose part or all of the missing matter of the …

The Simons Observatory (SO) is a new cosmic microwave background experiment being
built on Cerro Toco in Chile, due to begin observations in the early 2020s. We describe the …

Several pulsar timing arrays including NANOGrav, EPTA, PPTA, and CPTA have recently
reported the observation of a stochastic background of gravitational wave spectrum in the …

Axions comprise a broad class of particles that can play a major role in explaining the
unknown aspects of cosmology. They are also well-motivated within high energy physics …