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 …

The Swampland program aims to determine the constraints that an effective field theory must
satisfy to be consistent with a UV embedding in a quantum gravity theory. Different …

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 …

A bstract In this paper, we propose a new Swampland condition, the Trans-Planckian
Censorship Conjecture (TCC), based on the idea that in a consistent quantum theory of …

It has been notoriously difficult to construct a meta-stable de Sitter (dS) vacuum in string
theory in a controlled approximation. This suggests the possibility that meta-stable dS …

The recently introduced swampland criterion for de Sitter [17] can be viewed as a
(hierarchically large) bound on the smallness of the slow roll parameter 𝜖 V. This leads us to …

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 …

These lecture notes provide a pedagogical introduction, with exercises, to the techniques
used in attempts to construct vacua with stabilized moduli in string theory. The reader is only …

When the universe is treated as a quantum system, it is described by a wave function. This
wave function is a function not only of the matter fields, but also of spacetime. The no …

We give a brief overview of the string landscape and techniques used to construct string
compactifications. We then explain how this motivates the notion of the swampland and …