http://arxiv.org/abs/1509.06736
Recent measurements of the temperature field of Cosmic Microwave Background (CMB) indicates tantalising evidence for violation of Statistical Isotropy (SI) that constitutes a fundamental tenet of contemporary cosmology. Both CMB space based missions, WMAP and Planck have observed a $7\%$ departure in the SI temperature field at large angular scales. However, due to higher cosmic variance at low multipoles, the significance of this measurement is not expected to improve any from future CMB temperature measurement. We demonstrate that weak lensing of the CMB due to scalar perturbations produces a corresponding SI violation in $B$ modes of CMB polarization at smaller angular scales where the smaller cosmic variance leads to readily measurable effects for proposed future CMB missions. Due to much lower cosmic variance at small angular scales and high sensitivity of future missions, this effect is measurable at more than $7\sigma$. Such measurements could unambiguously establish the presence of SI violation in the Universe and further, can precisely determine any scale dependence of the observed hemispherical asymmetry.
S. Mukherjee and T. Souradeep
Wed, 23 Sep 15
8/63
Comments: 6 pages, 3 figures
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