Lunch seminar Dmitri Sorokin
|When:||Th 10-03-2016 12:30 - 13:30|
We will review a recent burst of interest to the study of the mechanism of spontaneous breaking of local supersymmetry induced by Volkov-Akulov goldstini in four-dimensional supergravity, related to the possibility of building relevant cosmological models with de Sitter vacua in the framework of supergravity and string theory. We will compare two realizations of this mechanism in the construction of the `de Sitter supergravity' action, one which uses constrained (nilpotent) superfields and another one involving a space-filling 3-brane . The latter can be regarded as a dimensionally reduced relic of anti-D-branes causing supersymmetry breaking and generating de Sitter vacua in corresponding stringy scenarios. We will also show that in the unitary gauge, in which the goldstino field is set to zero, the de Sitter supergravity action coincides with that of a Volkov-Soroka model of 1973.