HEP Theory Journal Club

Positive cosmological constant solutions from M theory

Mir Mehedi Faruk

McGill

The classical solutions of String theory do not give rise to a four-dimensional positive curvature spacetime with the isometries of de Sitter spacetime, as a consequence of the Maladacena Nunez No Go theorem. On the other hand, quantum corrections could allow for de Sitter solutions, provided that certain constraints are satisfied (arxiv:1402.5112). Unfortunately, a careful study showed that, generically, such a constrained system does not allow for an effective field theory description in four dimensions. It has been expected that a mild time dependency could allow the establishment of a hierarchy of quantum corrections, and an EFT description could be established (arxiv:1808.07498). We are currently looking into solutions with time dependency to allow spacetime with positive cosmological constant. I will try to summarise some of our contributions from the past few months.