Speaker
Ms
Junko Ohashi
(Tokyo University of Science)
Description
We study observational signatures of two classes of anisotropic
inflationary models in which an inflaton field couples to
(i) a vector kinetic term $F_{¥mu ¥nu}F^{¥mu ¥nu}$ and
(ii) a two-form kinetic term $H_{¥mu ¥nu ¥lambda}H^{¥mu ¥nu ¥lambda}$.
We compute the corrections from the anisotropic sources to the
power spectrum of gravitational waves as well as the two-point
cross correlation between scalar and tensor perturbations.
The presence of statistical anisotropies generally leads to
a suppressed tensor-to-scalar ratio $r$ and a smaller scalar
spectral index $n_s$. For the potentials of chaotic and natural inflation,
we place observational constraints on the model parameters and
the anisotropic parameter $g_*$ by using the recent Planck bounds
of $n_s$ and $r$.
Since the signs of $g_*$ are different depending on the vector
and two-form field models, the precise measurements of the
anisotropic scalar power spectrum can allow us to
discriminate between the two models further.
The non-linear estimator $f_{NL}$ of
scalar non-Gaussianities in the two-form field model
is generally smaller than that in the vector model for the same
level of anisotropies, so that the former is easier to be
compatible with the Planck bounds of non-Gaussianities
than the latter.
Primary author
Ms
Junko Ohashi
(Tokyo University of Science)
Co-authors
Prof.
Jiro Soda
(Kyoto University)
Prof.
Shinji Tsujikawa
(Tokyo University of Science)
