ACP Seminar (Astronomy - Cosmology - Particle Physics)

Speaker: Takahiro Tanaka (YITP)
Title: Natural selection of inflationary vacuum required by infra-red regularity and gauge-invariance.
Date (JST): Wed, May 18, 2011, 13:30 - 15:00
Place: Seminar Room A
Abstract: It has been an issue of debate whether the inflationary infrared (IR)
divergences are physical or not. Our claim is that, at least, in
single-field models, the answer is "No," and that the spurious IR
divergence is originating from the careless treatment of the gauge
modes. However, if we explicitly calculate the IR loop correction even
for genuine gauge-invariant quantities, we encounter divergent
expression. To remove this divergence, we also need to require the gauge
invariance in the choice of the initial vacuum, which is a new concept
that has not been considered in conventional calculations.