String Theory Seminars
Quantum infra-red effects in de Sitter space (through Skype)
by Hiroyuki Kitamoto (KEK, Japan)
Friday, July 27, 2012
from
to
(Asia/Kolkata)
at Colaba Campus ( A304 )
at Colaba Campus ( A304 )
Description |
Quantum field theory in de Sitter space is necessary to investigate physics in the past and present exponentially expanding universes from a microscopic view point. In particular, we focus on the quantum effects at the super-horizon scale. It is because there is a dS symmetry breaking mechanism and physical quantities may acquire time dependence as quantum effects. Gravitational field is an attractive candidate which induces such infra-red effects. I talk mainly about our recent works of soft graviton effects on the local dynamics of matter fields at the sub-horizon scale. We show that soft gravitational effects do not spoil Lorentz invariance in scalar, Dirac and gauge field theories. In the interacting field theory with quartic, Yukawa and gauge interactions, we find that the effective couplings are time dependent and the evolutions are physical as their relative scaling exponents are gauge invariant. |