Limits on Violations of Lorentz Symmetry and the Einstein Equivalence Principle using Radio-Frequency Spectroscopy of Atomic Dysprosium

TL;DR

This study uses atomic dysprosium spectroscopy to test Lorentz invariance and the Einstein equivalence principle, setting new limits on possible violations with high precision.

Contribution

It provides the first joint laboratory test of Lorentz invariance and the Einstein equivalence principle for electrons using atomic dysprosium.

Findings

Limits Lorentz violation for electrons at 10^{-17}

Improves bounds on gravitational redshift anomalies to 10^{-8}

Potential sensitivity to Lorentz violation at 9×10^{-20}

Abstract

We report a joint test of local Lorentz invariance and the Einstein equivalence principle for electrons, using long-term measurements of the transition frequency between two nearly degenerate states of atomic dysprosium. We present many-body calculations which demonstrate that the energy splitting of these states is particularly sensitive to violations of both special and general relativity. We limit Lorentz violation for electrons at the level of $10^{-17}$, matching or improving the best laboratory and astrophysical limits by up to a factor of 10, and improve bounds on gravitational redshift anomalies for electrons by 2 orders of magnitude, to $10^{-8}$. With some enhancements, our experiment may be sensitive to Lorentz violation at the level of $9\times 10^{-20}$.