Particle Physics Seminar: Crunching Away the Cosmological Constant Problem: Dynamical Selection of a Small Λ

Zoom: https://zoom.us/j/97485901126

Abstract: 

The Cosmological Constant (CC) problem is one of the greatest problems in modern physics. I will present the CC problem, as well as its most famous solution, which utilizes the anthropic principle. I will then present a new model that solves the problem with several interesting implications. In the new model, regions of space with a large CC are short-lived and are dynamically driven to crunch soon after the end of inflation. Conversely, regions with a small CC are metastable and long-lived and are the only ones to survive until late times. The model avoids the usual pitfall of eternal inflation by ensuring that after enough time passes, the entire universe crunches. Curiously, in the model, the weak scale arises as the geometric mean of the temperature in our universe today and the Planck scale, hinting at a new “CC miracle”, motivating new physics at the weak scale independent of electroweak physics. The talk is based on the recent preprint arXiv:1912.08840.

Seminar Organizers: Prof. Erez Etzion & Dr. Liron Barak