Cosmology with external fields

par Dr Júlio Fabris (UFES, Vitória, Brazil)

lundi 6 juil. 2015, 14:30 → 15:30 Europe/Paris

Amphithéâtre 5 (CPT)

Scalar fields are usually employed in cosmological contexts. In general, they are dynamics and subjected to the variational principle in a Lagrangian formulation. But, they can also be consider as external fields, being non-dynamical. In this case, its behaviour is dictated by some other considerations or by some constraints. Frequently, these external fields may be considered as an effective way of implement, at classical level, quantum effects in gravitation and cosmology. We discuss some consequences of considering such external scalar fields, mainly in cosmological context. In some specific cases, the achievements of the standard cosmological model can be preserved and, at the same time, some of its problems can be at least alleviated.