Analysis of atomic-clock data to constrain variations of fundamental constants

Abstract

We present a new framework to study the time variation of fundamental constants in a model-independent way. 
Model independence implies more free parameters than assumed in previous studies.
Using data from atomic clocks based on $^{87}$Sr, $^{171}$Yb$^+$ and $^{133}$Cs, we set bounds on parameters controlling the variation of the fine-structure constant, $\alpha$, and the electron-to-proton mass ratio, $\mu$. We consider variations on timescales ranging from a minute to almost a day. In addition, we use our results to derive some of the tightest limits to date on the parameter space of models of ultralight dark matter and axion-like particles.

Axio-Chameleons: a novel string-friendly multi-field screening mechanism

“…We choose the matter scale Λ m to ensure the matter interaction (4.7) evades the constraints described in the previous section. To this end we conservatively ask that U (a) not shift particle masses δm ψ /m ψ ≃ U (a) by more than a part in 10 15 so as to not contribute observably to atomic clock measurements on earth (see [84] for a recent…”

171Yb+ optical clock with 2.2 × 10 − 18

“…Another feature of 171 Yb + is the presence of a second favourable optical clock transition, the electric quadrupole (E2) transition 2 S 1/2 → 2 D 3/2 [8], with a narrow enough natural linewidth (3.1 Hz) to make it suitable as a frequency standard, which can be utilised to help determine systematic effects on the E3 transition. Furthermore, the E3 transition has a strong sensitivity to the variation of the fine structure constant, which makes 171 Yb + ideal for testing fundamental physics [9][10][11][12].…”