Measurement of Differential Static Polarizability and Frequency of an Inner-Shell Orbital Clock Transition in Lattice-Trapped 174Yb

TL;DR

This study precisely measures an inner-shell orbital transition in lattice-trapped 174Yb atoms, revealing its low polarizability and establishing a frequency ratio with the well-known clock transition, advancing the search for new physics beyond the Standard Model.

Contribution

The paper reports the first high-resolution observation and measurement of the 431 nm inner-shell orbital transition in 174Yb, including its differential static polarizability and frequency ratio with the standard clock transition.

Findings

Observed 4.3 Hz linewidth spectra of the transition.

Measured the differential static polarizability as -2.10(4) kHz/(kV/cm)^2.

Determined the transition frequency to be approximately 695.175 THz.

Abstract

Additional clock transitions of ytterbium atoms based on inner-shell orbital transition could benefit the search for new physics beyond the Standard Model. Observation of these transitions with high resolution is a prerequisite for making precise frequency measurements. Here, we observe 4.3 Hz-linewidth spectra of the inner-shell orbital transition at 431 nm in lattice-trapped 174Yb. With high-resolution spectra, we precisely determine the differential static polarizability of the transition to be -2.10(4) kHz/(kV/cm)^2. The magnitude of this polarizability is approximately 1/17 of that of the well-known clock transition in 171Yb at 578 nm, indicating a reduced sensitivity to blackbody radiation. We carry out a frequency ratio measurement between the two clock transitions of ytterbium atoms with an uncertainty of 9E-15. The frequency of the 431 nm transition is determined to be 695 175 030 801 776.5(6.3) Hz. These results represent a step forward in future studies on the search for new physics beyond the Standard Model.