Oscillating-magnetic-field effects in high-precision metrology

Abstract

We examine a range of effects arising from ac magnetic fields in high precision metrology. These results are directly relevant to high precision measurements, and accuracy assessments for state-ofthe-art optical clocks. Strategies to characterize these effects are discussed and a simple technique to accurately determine trap-induced ac magnetic fields in a linear Paul trap is demonstrated using 171 Yb + .

Inner-shell clock transition in atomic thulium with a small blackbody radiation shift

“…BBR magnetic field: To estimate the clock transition frequency shift due to the magnetic component of BBR, we follow the analysis given in the work 46 . The corresponding frequency shift of one of the clock levels coupled to another atomic level with magnetic-dipole transition at frequency ω 0 can be found by integrating over the full BBR spectrum as follows:where ε 0 is the vacuum permittivity, T 0 = 300 K, and y = ℏ ω 0 / k B T .…”

Al+27 Quantum-Logic Clock with a Systematic Uncertainty below 10Brewer1, Chen2, Hankin3 et al. 2019Phys. Rev. Lett.55132950View full textAdd to dashboardCite

“…The quadratic Zeeman shift is given by ∆ν/ν = C 2 B 2 , where C 2 is the quadratic Zeeman coefficient and B 2 = B DC 2 + B 2 AC [9,15]. Here B DC is the static magnetic field measured in real-time and B AC is constrained based on microwave frequency measurements made on the 25 Mg + ion as well as the uncertainty in the hyperfine constant A hf s [30]. We have recently made improved measurements of both C 2 and A hf s that are presented elsewhere [31].…”

Laser-cooled ytterbium-ion microwave frequency standard

“…For a perfectly symmetric trap, the magnetic fields generated by these currents will cancel along the nodal line of the trapping field. However, if the ions are not centered, or if the currents are not symmetric, an oscillating magnetic field will cause an AC Zeeman shift [41,42]. The fractional frequency shift from this effect was calculated to be below 1×10 −15 .…”

“…The instability due to fluctuating magnetic fields is small compared to the instability from the shot-noise. There is also an AC second-order Zeeman shift that arises from oscillating magnetic fields [41]. The oscillating magnetic fields are primarily from two sources, 50 Hz mains AC and the RF trap drive.…”