BSM-PM: High Precision Laser Spectroscopy of Hydrogen and Deuterium as a Test for New Physics

For this project the internal quantum states of atomic hydrogen and deuterium will be measured using lasers. Hydrogen is the simplest atom and is comprised of only one electron and one proton. Deuterium is similar in that it has only a single electron, but with both a proton and a neutron in its nucleus. Since these atoms are very simple, their theoretical description can be made very precise by including many subtle quantum mechanical processes which are too challenging to include for atoms with many electrons. For one research direction, the energy difference between two quantum levels in hydrogen will be measured with the help of a state-of-the-art atomic clock co-located within the same building. The goal is to measure this energy difference with an uncertainty approaching one part in a quadrillion (a thousand trillion). In a second research direction, the quantum states in hydrogen and deuterium will be directly compared. With advanced theory, this will allow for an investigation of any small interaction between the electron and neutron which has so far gone undetected. These two projects will provide sensitive tests of our best quantum mechanical theories of nature or possibly provide indications of new physical laws. The planned experiments will prepare students to enter the quantum workforce by providing training in atomic, molecular, and optical physics, laser science, and precision measurement. The goal of this project is to perform high-precision laser spectroscopy of atomic hydrogen and deuterium in order to test quantum electrodynamics. The spectroscopy will be performed on a cryogenic and velocity-characterized hydrogen/deuterium beam, and the spectroscopy laser will use cavity-enhanced continuous-wave lasers referenced to an optical frequency comb. One measurement pursued will be the 1S-2S transition in hydrogen, which provides the lynchpin in our theoretical description of hydrogen and allows for the most precise determination of the Rydberg constant. This measurement will use a separated-oscillatory fields method and will be referenced to a ytterbium ion optical atomic clock, collocated in the physics building, to measure this transition with a relative uncertainty of one part per quadrillion. A second measurement will be spectroscopy of the deuterium 2S-nS two-photon transitions (with n between 8 and 10) with relative uncertainties on the order of one part per trillion. This will build on measurements of those same transitions in hydrogen allowing for a sensitive comparison of the two species. This comparison can be used to search for an anomalous interaction between the neutron and electron. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2607661 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Dylan Yost | Institution: Colorado State University, FORT COLLINS, CO | Award Amount: $592,969 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2607661 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2607661.html