Observations of the Cosmic Microwave Background(CMB) have cemented the notion that the large-scale Universe is both statistically homogeneous and isotropic. But is it invariant also under mirror reflections? Recently, observations of CMB polarization (through birefringence) and the distribution of galaxies (through four-point functions, or trispectra) have challenged this notion, and give tentative evidence for new parity-violating processes at work in the early or late Universe. In this talk, the speaker will discuss these measurements, focusing primarily on the parity-violating signature seen in the BOSS galaxy sample. He will present an overview of how the measurements are made and interpreted before commenting on possible explanations for the signal, both in terms of new physics (from inflation or modified gravity) and systematics (in the observations or analysis). He will further outline the possibilities for solving this cosmic controversy with new data in the coming years.
頻道：Zoom ID:942-338-0685 ← gravity
講者：Oliver Philcox (Columbia University)
Copernicus Webinar and Colloquium Series: to promote scientific discussions during this pandemic, they are organizing an online seminar series, i.e. Copernicus Webinar Series, seeking the most outstanding speakers to introduce innovative ideas and important progress in the field of gravity and cosmology. This series is named after the famous Polish Astronomer, Nicolaus Copernicus, whose discovery eventually marked the dawn of modern science.