HE Seminar - 10/18/24 - Emilian Dudas - Ecole Polytechnique

This week's High Energy Theory Seminar was presented by Dr. Emilian Dudas from the Ecole Polytechnique in France. The title of his talk is, “On Energy and Particle Production in Cosmology: The Particular Case of the Gravitino .”

Abstract: The number of particles produced in cosmology, defined from the Fock space of the instantaneous hamiltonian, is ambiguous. The energy computed from the energy-momentum tensor should be physical. We compare the corresponding Fock spaces and relate them through a Bogolyubov transformation. For the spin 3/2, one finds two puzzles. The first is that the two corresponding Fock spaces do not match even in the limit of high momenta. The second is that whereas we provide evidence for the equivalence theorem between longitudinal gravitinos and the goldstino in terms of an exact matching between the lagrangians and the instantaneous hamiltonians, the energy operator is not captured in a simple way by the goldstino action.