S-Wave Collisional Frequency Shift of a Fermion Clock

TL;DR

This paper demonstrates an s-wave collisional frequency shift in fermionic atomic clocks, revealing unique dependence on pulse areas and implications for optical lattice clock accuracy.

Contribution

It introduces the first observation of fermion clock shifts influenced by pulse areas, highlighting a new control mechanism for optical lattice clocks.

Findings

Fermion clock shift is insensitive to population difference, unlike bosons.

Shift depends strongly on the second pulse area, allowing cancellation.

Shift increases with spatial inhomogeneity of the excitation field.

Abstract

We report an s-wave collisional frequency shift of an atomic clock based on fermions. In contrast to bosons, the fermion clock shift is insensitive to the population difference of the clock states, set by the first pulse area in Ramsey spectroscopy, \theta_1. The fermion shift instead depends strongly on the second pulse area \theta_2. It allows the shift to be canceled, nominally at \theta_2 = \pi/2, but correlations shift the null to slightly larger \theta_2. The shift applies to optical lattice clocks and increases with the spatial inhomogeneity of the clock excitation field, naturally large at optical frequencies.