Atomic clocks with suppressed blackbody radiation shift

TL;DR

This paper proposes a novel atomic clock concept that significantly reduces blackbody radiation shifts by using a synthetic frequency derived from two clock transitions, enabling highly stable timekeeping near room temperature.

Contribution

The authors introduce a new method to suppress blackbody radiation shifts in atomic clocks using a synthetic frequency from two transitions, enhancing stability independently of environmental temperature.

Findings

Blackbody radiation shift can be suppressed by 1-3 orders of magnitude.

Synthetic frequency is largely immune to temperature fluctuations.

Implementation with ion 171Yb+ can achieve 10^{-18} fractional stability.

Abstract

We develop a nonstandard concept of atomic clocks where the blackbody radiation shift (BBRS) and its temperature fluctuations can be dramatically suppressed (by one to three orders of magnitude) independent of the environmental temperature. The suppression is based on the fact that in a system with two accessible clock transitions (with frequencies v1 and v2) which are exposed to the same thermal environment, there exists a "synthetic" frequency v_{syn} (v1-e12 v2) largely immune to the BBRS. As an example, it is shown that in the case of ion 171Yb+ it is possible to create a clock in which the BBRS can be suppressed to the fractional level of 10^{-18} in a broad interval near room temperature (300\pm 15 K). We also propose a realization of our method with the use of an optical frequency comb generator stabilized to both frequencies v1 and v2. Here the frequency v_{syn} is generated as one of the components of the comb spectrum and can be used as an atomic standard.