Institute for Advanced Study/Princeton University Early Universe/Cosmology Lunch Discussion

Topic 1: N-point Correlation Functions — Work in Progress and Outlook Topic 2: Anisotropies of icosahedral inflation

Abstract 1: Gravitational evolution induces nonlinearities in the large-scale structure at late times in the Universe. Information that was fully captured by the two-point statistics at the early times gets spread into higher-order statistics. Whilst current standard cosmological analyses have focused on two-point statistics, higher-order statistics consequently help further to tighten constraints and break parameter degeneracies. In this talk, I will present our recent progress on the N-point Correlation Function (NPCF), including an analytical Gaussian covariance formalism, aspect of using GPU to accelerate the NPCF measurement algorithm, and layout our ideas for using the NPCF in probing fundamental physics in the future.

Abstract 2: In this talk, I will present recent work done on analyzing the unique observational imprints of icosahedral inflation. Icosahedral inflation is a special case of solid inflation, in which the dynamics of the system are driven by a triplet of scalars satisfying internal icosahedral symmetry. This model is motivated by a hunt for an intrinsically anisotropic symmetry that gives isotropic background stress tensor and two-point function, and indeed the model predicts a completely isotropic scalar power spectrum while introducing anisotropic corrections to the tensor power spectrum and the bispectrum. A mixed scalar-tensor two-point function is also allowed. Observationally, it is possible to have a maximally anisotropic scalar bispectrum, and non-zero T-B and E-B correlations for the CMB temperature-polarization spectrum. These statistical anisotropies also give rise to non-zero bipolar spherical harmonics and bipolar power spectrum, which are calculated and will be discussed in the talk.

Date & Time

October 18, 2021 | 12:30pm – 2:00pm


Zoom; IAS, West Seminar Room


Jiamin Hou and Guanhao Sun

Speaker Affiliation

University of Florida and Columbia University