The String Theory Swampland in the Euclid, Square Kilometer Array, and Vera Rubin Observatory Era

Abstract

Abstract This article aims to draw the attention of astronomers to the ability of future cosmological surveys to put constraints on string theory. The fact that “quantum gravity” might be constrained by large-scale astrophysical observations is a remarkable fact that has recently concentrated a great amount of interest. In this work, we focus on future observatories and investigate their capability to put string theory, which is sometimes said to be “unfalsifiable,” under serious pressure. We show that the combined analysis of the Square Kilometer Array, Euclid, and the Vera Rubin observatory—together with Planck results—could substantially improve the current limits on the relevant string swampland parameter. In particular, our analysis leads to a nearly model-independent prospective upper bound on the quintessence potential, , in strong contradiction of the so-called de Sitter conjecture. Some lines of improvements for the very long run are also drawn, together with generic prospective results, underscoring the efficiency of this approach. The conjectures used in this work are discussed pedagogically, together with the cosmological models chosen in the analysis.