The exploration of the universe has recently entered a new era thanks to the multi-
messenger paradigm, characterized by a continuous increase in the quantity and quality of …

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 …

Following the discovery of spacetime anomaly cancellation in 1984 [1], string theory has
undergone rapid development in several directions. The early hope of making direct contact …

We review the status of solitons in superstring theory, with a view to understanding the
strong coupling regime. These solitonic solutions are non-singular field configurations which …

We study the cosmological solutions of the one-loop corrected superstring effective action, in
a Friedmann-Robertson-Walker background, and in the presence of the dilaton and …

We describe string vacuum configurations for which the radii (moduli) of the internal compact
space vary in four-dimensional space-time, focusing on configurations which have the …

Aspects of string cosmology for critical and non-critical strings are discussed emphasizing
the necessity to account for the dilaton dynamics for a proper incorporation of “large-small” …

Dynamical systems theory is especially well-suited for determining the possible asymptotic
states (at both early and late times) of cosmological models, particularly when the governing …

Within a Liouville approach to noncritical string theory, we discuss space–time foam effects
on the propagation of low-energy particles. We find an induced frequency-dependent …

Instantons and soliton solutions of heterotic string theory are investigated with an emphasis
on the worldsheet point of view. The solitons have the structure of a fivebrane in ten …