Wed, Aug 19 2024, 10am
Jiangwan S140
Astro Seminar: Probing the Origin of Big Bang Cosmology: Cosmological Collider Physics and Primordial Standard Clocks
Prof. Xingang Chen (Harvard-Smithsonian Center for Astrophysics)
Abstract: Despite the tremendous success of the hot big bang model, its mysterious initial conditions imply the existence of a proceeding primordial epoch beyond the scope of the current standard model of cosmology. The high energy scale of this primordial epoch excites massive fields, imprinting their signatures on primordial fluctuations which eventually seeded the structure of the entire universe. These imprints can reveal the nature of particle physics beyond the reach of terrestrial colliders. Additionally, some of these signals encode critical information about the primordial epoch itself, helping us determine whether this epoch is inflationary or non-inflationary. We review the theoretical and observational aspects of these two research programs and the intricate relationships between them.
Bio: Xingang Chen is a theoretical cosmologist at the Harvard-Smithsonian Center for Astrophysics. He earned his Bachelor's degree from Fudan University in 1996 and his Ph.D. from Columbia University in 2003. From 2009 to 2013, he was a Stephen Hawking Advanced Fellow at the University of Cambridge. Chen proposed and advanced the field of Primordial Standard Clocks, whose signals can be used to observationally differentiate between various primordial universe scenarios proposed to explain the origin of Big Bang Cosmology. Together with Yi Wang, Chen pioneered the research field now commonly known as Cosmological Collider Physics, which explores how the properties of elementary particles at subatomic scales manifest as statistical properties of our Universe on the largest scales through cosmic inflation. He has also made important contributions to the innovation and classification of mechanisms of primordial non-Gaussianities and primordial features in early universe cosmology.
