Speaker
Description
Similar to atomic hydrogen, precision laser spectroscopy of atomic deuterium can be used to determine physical constants and to test Quantum Electrodynamics. A combination of the 1S-2S transition frequency with additional measurements in deuterium allows a determination of the deuteron radius independent of the proton radius (1). These determinations are however discrepant with results obtained in muonic deuterium (2), similar to the proton radius puzzle in hydrogen. Contrary to hydrogen (e.g. (3)), no recent measurements in deuterium are available.
In contrast to hydrogen, precision spectroscopy of the same transition in deuterium is complicated by the simultaneous excitation of unresolved hyperfine components, possibly leading to quantum interference between unresolved lines (4). Since these effects depend on laser polarization, we developed an active fiber-based retroreflector with a polarization monitor (5). Furthermore, we find that in our case the quantum interference is strongly suppressed. We performed a preliminary measurement of the 2S-6P transition in deuterium, which demonstrates the feasibility of determining this transition frequency with a similar precision as for hydrogen.
References
(1) R. Pohl et al., Metrologia 54, L1 (2017)
(2) R. Pohl et al., Science 353, 669–673 (2016)
(3) A. Brandt et al., Phys. Rev. Lett 128, 023001 (2022)
(4) Th. Udem et al., Ann. Phys. 531, 1900044 (2019)
(5) V. Wirthl et al., Opt. Express 29(5), 7024-7048 (2021)
