This research program is aimed at performing precision co-magnetometry using atomic physics tools to enable sensitive searches for new physics beyond the Standard Model of particle physics. These experiments will employ a dual-species maser operating simultaneously with optically-pumped Xenon-129 and Helium-3 gas. By using one of the noble-gas masers as a co-magnetometer, and stabilizing its maser frequency by comparison to an atomic clock, one can precisely control the magnetic field environment of the second noble-gas maser and then employ this maser as a very sensitive sensor for new physics that couples to the noble gas nucleus, with no significant contribution from the atomic electrons. The experiments to be carried out include a sensitive test of Lorentz symmetry (one of the fundamental aspects of the theory of relativity) and CPT (Charge conjugation, Parity, and Time reversal) symmetry for the neutron.
Broader impacts of the program include the application of the atomic physics based precision measurement techniques of this research into the development of novel tools for magnetometry and bioimaging. Magnetic resonance imaging (MRI) at low magnetic fields of hyperpolarized noble gas inhaled into human lungs and atom-like Nitrogen Vacancy (NV) color centers in diamond, which may provide sensitive magnetometers to monitor electromagnetic activity in neuronal networks, are two examples.
In this project we developed, implemented, and tested upgrades of a kind of atomic clock that uses two types of noble has (3He and 129Xe). This "noble gas maser" may enable a sensitive test of fundamental properties of spacetime for the neutron, as well as an improved search for the effects of novel ‘torsion’ effects of gravity. We also pursued theoretical investigations of possible new spacetime effects that we may be able to search for in future experiments using sensitive measurements of the polarization of light. Note that these high-precision experiments employ sensitive measurements tools such as atomic clocks to provide a complementary, small-scale approach to answering "big science" questions such as whether there is a preferred reference frame to the universe, and how can we reconcile the (at times) inconsistent predictions of quantum theory and relativity. As a broader impact of this research, we continued development of precision optically-probed and polarized electronic spins associated with nitrogen vacancy (NV) color centers found in diamond. We explored possible experimental applications of NV-diamond to searches for short-range anomalous forces as evidence of new fundamental physics. Our work also aided the development of NV-diamond magnetometers, which may have wide-ranging impact in both the physical and life sciences. Students and postdoctoral researchers were active participants in all phases of this research: design, construction, and execution of experiments; detailed calculations; analysis of data; presentation of results at scientific meetings; and writing scientific papers. In addition, the Principal Investigator (Dr. Walsworth) described the scientific process and results from this NSF-supported research in a wide variety of presentations ranging from scientific conferences and seminars to public lectures.
