String theory provides a framework for quantising gravity and unifying it with the other fundamental interactions. A major chal- lenge is to identify our universe among a huge amount of ground states forming the string landscape. In a bottom-up approach, the swampland program consists of defining a set of criteria for low energy effective field theories that have a consistent ultraviolet completion within string theory (or within quantum gravity in general); therefore, those that do not satisfy these criteria belong to the swampland and not to the string landscape. This issue presents the progress made over the recent years on understanding the structure of the string landscape and on providing a complete set of swampland criteria and their consequences.
Topics may include but are not limited to:
LPTHE - CNRS - Faculty of Science, Sorbonne University, Paris, France
ITP - Albert Einstein Centre, University of Bern, Bern, Switzerland
Centre de Physique Théorique, CNRS, École Polytechnique, IP Paris, F-91128 Palaiseau, France
Laboratoire de Physique Théorique et Hautes Energies (LPTHE), UMR 7589,
Sorbonne Université et CNRS, 4 place Jussieu, 75252 Paris Cedex 05, France.