Primordial Non-Gaussianity

Abstract

Our current understanding of the Universe is established through the pristine\nmeasurements of structure in the cosmic microwave background (CMB) and the\ndistribution and shapes of galaxies tracing the large scale structure (LSS) of\nthe Universe. One key ingredient that underlies cosmological observables is\nthat the field that sources the observed structure is assumed to be initially\nGaussian with high precision. Nevertheless, a minimal deviation from\nGaussianityis perhaps the most robust theoretical prediction of models that\nexplain the observed Universe; itis necessarily present even in the simplest\nscenarios. In addition, most inflationary models produce far higher levels of\nnon-Gaussianity. Since non-Gaussianity directly probes the dynamics in the\nearly Universe, a detection would present a monumental discovery in cosmology,\nproviding clues about physics at energy scales as high as the GUT scale.