LOEB LECTURE - ARVANITAKI, Asimina, "The Cosmic Neutrino Background (CνB)" - 03/20/23

Harvard University, Department of Physics
Morris Loeb Lecture Series in Physics
March 20, 2023

ASIMINA ARVANITAKI
(Perimeter Institute)
"The Cosmic Neutrino Background (CνB): Its distribution on the surface of the Earth and its manipulation on laboratory scales"

Abstract:
The CνB is a cosmological relic analogous to the CMB, and contains information about the universe when it was just one-second-old. I will argue that reflection of relic neutrinos from the surface of the Earth creates a significant local neutrino-antineutrino asymmetry in a shell seven meters thick around the Earth's surface. This asymmetry far exceeds the expected primordial lepton asymmetry. The resulting gradient of the net neutrino density provides a way-out of a forty-year-old “no-go” theorem on the vanishing of O(G_Fermi) neutrino forces on matter.

These forces can be further enhanced by using 1-100 meter structures with shape reminiscent of a sea-urchin: they consist of rods of width w and length L w periodically arranged on the surface of the sphere of radius R~L. Such a structure functions as a diffraction grating for relic neutrinos and the induced neutrino-antineutrino asymmetry at its center may point to a new class of experiments to detect the CνB in a laboratory setting. At the same time, such structures can be used to similarly manipulate dark matter. The simplicity of this proposal suggests there may be significant improvements that escape us.

Bio:
Asimina Arvanitaki (PhD Stanford University, 2008) is the Stavros Niarchos Foundation Aristarchus Chair in Theoretical Physics at Perimeter Institute, where she has been a faculty member since 2014. She previously held research positions at the Lawrence Berkeley National Laboratory at the University of California, Berkeley (2008-11), and the Stanford Institute for Theoretical Physics at Stanford University (2011-14).

Asimina is a particle physicist who specializes in designing new experiments to test fundamental theories beyond the Standard Model. These experiments rely on the latest developments in metrology, such as atomic clocks, and the optical trapping and cooling of macroscopic objects. She recently pioneered a new experiment that can look for new spin-dependent forces in nature at an unprecedented level of precision. Arvanitaki also works on theoretical challenges raised by experimental results, such as a model of particle physics influenced by string theory called "split SUSY." In 2016, she received an Early Researcher Award from the Ministry of Research and Innovation of Ontario.