Monday, June 4 2018
14:30 - 17:00

Alladi Ramakrishnan Hall

The standard model of cosmology and beyond: constraints and forecasts

Dhiraj Hazra

Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Bologna

The standard model of cosmology assumes the primordial perturbations to be
Gaussian and to have a power law spectrum. Supporting observations also
suggest that the Universe consists of baryons, radiation, cold dark matter
and cosmological constant as dark energy. Cosmic Microwave Background (CMB)
temperature and polarization spectra are the best probes till date, to test
most of these assumptions. I will discuss a model independent
reconstruction of the primordial power spectrum directly using the CMB
angular power spectrum data from Planck. Direct reconstruction hints
towards possible features in the data, which in turn indicate non-trivial
inflationary dynamics. I will demonstrate the generation of these features
in the primordial power spectra involving canonical scalar field driven
inflation models, particularly in the Wiggly Whipped Inflation framework. I
will introduce the BI-spectra and Non-Gaussianity Operator (BINGO) for the
efficient numerical computation of the primordial power spectrum and
bi-spectrum. After presenting the recent constraints on the primordial
features, I will discuss the extent to which we will be able to identify
these features with future space based CMB surveys. Introducing poly-reion
(a new free-form parametrization of the history of reionization), I will
present model independent constraints on reionization from CMB and quasar
data. Using this non-standard model of reionization history, I will address
its degeneracies with other cosmological processes in the CMB data. Towards
the end of my talk, in order to examine another assumption of the standard
model, I will discuss a model independent test of the isotropy of the
matter dominated Universe using the Lyman-alpha forest data from the high
redshift quasars.

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