Correlated adiabatic and isocurvature CMB fluctuations after the WMAP
by Jussi Valiviita in Cosmo-03 in Ambleside, U.K., 25th August 2003.
Abstract
In multi-field inflation models, correlated adiabatic and isocurvature fluctuations are
produced and in addition to the usual adiabatic fluctuation with a spectral index n_ad1
there is another adiabatic component with a spectral index n_ad2 generated by entropy
perturbation during inflation, if the trajectory in the field space is curved. Allowing
n_ad1 and n_ad2 to vary independently we find that the WMAP data favour models where the two
adiabatic components have opposite spectral tilts. This leads naturally to a running
adiabatic spectral index. The WMAP data with a prior n_iso < 1.84 for the isocurvature
spectral index gives f_iso < 0.84 for the isocurvature fraction of the initial power
spectrum at k_0 = 0.05 Mpc^{-1}. We also comment on a degeneration between the correlation
component and the optical depth tau. Moreover, the measured low quadrupole in the TT angular
power could be achieved by a strong negative correlation, but then one would need a large tau
to fit the TE spectrum.
- 13 overheads with complete explanations as a
ps file or a
pdf file.
- Some useful links and references
- This talk is based on:
J. Valiviita and V. Muhonen,
Phys. Rev. Lett. 91, 131302 (2003)
[arXiv:astro-ph/0304175].
- Quite the similar talk in Blois: J. Valiviita,
[arXiv:astro-ph/0310206].
- Ruling out pure CDM isocurvature fluctuations:
K. Enqvist, H. Kurki-Suonio and J. Valiviita,
Phys. Rev. D 65, 043002 (2002)
[arXiv:astro-ph/0108422].
- Constraints on uncorrelated models with Boomerang and Maxima data:
K. Enqvist, H. Kurki-Suonio and J. Valiviita,
Phys. Rev. D 62, 103003 (2000)
[arXiv:astro-ph/0006429].
Last modified: Thu Oct 23 17:49:55 EEST 2003