This talk focuses on recent developments in test of fundamental physics, especially the matter-antimatter asymmetry and searches for dark matter and exotic interactions, using atoms. Recently, exotic spin-dependent interactions, predicted by many theoretical extensions of the Standard Model of particle physics, has attracted much attention in the community of physicists. Such theories are associated with the spontaneous breaking of continuous symmetries, leading to massless or very light Nambu-Goldston bosons such as the axion, axion-like-particles (ALPs), and hidden photons which are also candidates for cold dark matter.  These exotic spin-dependent interactions can be described as the interaction of the effective magnetic field with the spin, which can be detected by sensitive magnetometers. I will present several novel experimental approaches to search for exotic spin-dependent interactions using various magnetometers, e.g., spin-exchange relaxation-free magnetometer, diamond quantum magnetometer, and polarized helium-3 gas. Additionally, I will also discuss the recent development of the cosmic axion searches at LANL using a LC circuit in a strong magnetic field detecting by a RF optically pumped magnetometer. 

Biography:

Dr. Pinghan Chu joined Prof. Jen-Chieh Peng’s group in University of Illinois at Urbana-Champaign in 2006 working on the “dressed spin technique” in the neutron EDM experiment. After receiving his PhD degree in 2011, he worked on the search for exotic spin-dependent interactions with Prof. Haiyan Gao at Duke University. In 2014, he joined Dr. Steve Elliott’s group at Los Alamos National Laboratory (LANL) working on neutrinoless double-beta decays in 76Ge using high-purity germanium detectors. He became a scientist staff in LANL in 2019. Since then, he has worked on different topics including exotic spin-dependent interactions, neutrino physics, rare nuclear decay and dark matter searches.