Anisotropic non-Gaussianity from Rotational Symmetry Breaking Excited Initial States

Understand

If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations.

• This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation.
• The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be $|B| \lesssim 0.06$.
• The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations.