Precise determination of the isotope shift of ${}^{88}$Sr - ${}^{87}$Sr optical lattice clock by sharing perturbations

TL;DR

This paper precisely measures the isotope shift between two strontium isotopes using an innovative interleaved optical lattice clock technique that cancels common perturbations, achieving high accuracy and reducing uncertainties.

Contribution

The study introduces a method for accurately determining isotope shifts by sharing perturbations in an interleaved optical lattice clock setup, significantly reducing measurement uncertainties.

Findings

Isotope shift between ${}^{88}$Sr and ${}^{87}$Sr is 62,188,134.004 Hz.

Achieved fractional uncertainty of $2 imes 10^{-17}$ in frequency measurement.

Method effectively cancels common perturbations, improving measurement precision.

Abstract

We report on the isotope shift between ${}^{88}$Sr and ${}^{87}$Sr on the ${}^1S_0 - {}^3P_0$ clock transitions. The interleaved operation of an optical lattice clock with two isotopes allows the canceling out of common perturbations, such as the quadratic Zeeman shift, the clock-light shift, and the blackbody radiation shift. The isotope shift is determined to be 62 188 134.004(10) Hz, where the major uncertainty is introduced by the collisional shift that is distinct for each isotope. Our result allows us to determine the frequency of $^{88}$Sr-$^{87}$Sr optical lattice clocks with a fractional uncertainty of $2\times 10^{-17}$. The scheme is generally applicable for measuring the isotope shift with significantly reduced uncertainty.