Theory HEP Seminar

de Sitter state in string theory

Archana Maji

Indian Institute of Technology Bombay

Various no-go theorems and swampland criterion proposed over the past few decades has ruled out classical de Sitter vacua in string theory. Due to the absence of a well defined Wilsonian effective action such time dependent vacua with de Sitter isometries are not allowed even in the presence of quantum corrections. It was shown that a de Sitter solution can still be realised in type IIB string theory as a Glauber-Sudarshan (GS) state, i.e. as a coherent state, over a supersymmetric Minkowski background. We will discuss the chain of dualities leading to a GS state in SO(32) heterotic string theory with de Sitter isometries. The path integral analysis in M theory with respect to such a state leads to an asymptotic series which requires implementation of Borel resummation techniques and hence resurgence plays an important role in our construction. This in turn allows us to write an expression of the cosmological constant arising completely non-perturbatively and provides strong hints towards its positivity.