Name: I-Chin Wang
 Institution: Department of Physics, NTNU
 Title: Effects of a pre-inflation radiation-dominated epoch to CMB anisotropy
 Key Words: quadrupole,inflaton fluctuations,CMB anisotropy
 Abstract: We consider that the pre-inflation era is radiation-dominated,
transiting smoothly to the inflationary era. We work out in detail
the dynamics of inflaton fluctuations across the phase transition
and the proper choices of initial vacuum states. It is found that
this phase transition can suppress long-wavelength quantum
fluctuations of inflaton. This may attribute to the large-scale
CMB anisotropy a lower power than predicted in the standard
$\\Lambda$CDM model. In constraining this transitional effect by
WMAP anisotropy data, we use the WMAP best-fit scale-invariant
$\\Lambda$CDM model with the density power spectrum replaced by the
one found in this work. We find that the transition occurs at
least about $10$ e-folds before the comoving scales comparable to
our present horizon size cross the Hubble radius during inflation.