Events Daily

Friday, October 29, 2021

A technical analog of the cosmological constant problem and a solution thereof
Guanhao Sun, Columbia
Event Type: Informal HEP Talk
Time: 1:00 PM - 2:00 PM
Location: 726 Broadway, 940, CCPP Seminar
Abstract: The near vanishing of the cosmological constant is one of the most puzzling open problems in theoretical physics. I will talk about a system, the so-called framid, that features a technically similar problem. Its stress-energy tensor has a Lorentz-invariant expectation value on the ground state, yet there are no standard, symmetry-based selection rules enforcing this, since the ground state spontaneously breaks boosts. I will verify the Lorentz invariance of the expectation value in question with explicit one-loop computations. These, however, yield the expected result only thanks to highly nontrivial cancellations, which are quite mysterious from the low-energy effective theory viewpoint.

Intellectually Stimulating Craic
Iraj Eshghi, New York University
Event Type: Other
Time: 6:00 PM - 8:00 PM
Location: 726 Broadway, 940, CCPP Seminar