In addition to facilitating many of the advances in modern physics during the 20th century, the study of atomic hydrogen and other simple two-body systems remains a fresh and exciting topic. By probing hydrogen, one can precisely determine the Rydberg constant, proton charge radius, and ultimately test quantum electrodynamics. Currently, the determination of the proton charge radius through laser spectroscopy of hydrogen and muonic hydrogen (a simple atom consisting of a proton and a muon) is controversial and could indicate some physics beyond the Standard Model. Additional measurements in hydrogen will almost certainly be required to resolve this discrepancy.
In this talk, I will discuss our plans to improve the spectroscopy of hydrogen and other simple atoms. For atomic spectroscopy, the finite temperature of the atomic sample is often the primary limitation in the achievable precision. Therefore, the best measurements are usually made by first laser cooling the atoms. Unfortunately, conventional laser cooling of hydrogen (and other simple atoms) requires very short wavelength lasers, which are challenging to develop. To partially circumvent this challenge, we are developing a two-photon laser-cooling scheme that will use a high power 243 nm laser source to drive the hydrogen 1S-2S transition. Through this, we hope to achieve rapid deceleration and cooling of an atomic hydrogen beam within a 2-D magnetic guide. In addition, I will discuss recent progress towards the development of a more conventional laser cooling scheme using a Lyman-alpha laser source (121.6 nm) that will be used to cool trapped anti-hydrogen (an atom consisting of an anti-proton and a positron) within the ATRAP collaboration. By precisely comparing measurements of hydrogen and anti-hydrogen with laser spectroscopy, we hope to better understand the intrinsic asymmetries between matter and antimatter.
Argonne Physics Division Seminar Schedule