Precision tests of General Relativity with Matter Waves

TL;DR

This paper reviews how matter-wave interferometers and clocks can test Einstein's Equivalence Principle, highlighting their sensitivity to EEP violations and proposing new experimental approaches with isotopes.

Contribution

It demonstrates the equivalence of clocks and matter-waves in testing EEP and compares their sensitivities, suggesting novel experiments with unstable isotopes.

Findings

Matter-wave interferometers and clocks are similarly sensitive to EEP violations.

Comparisons of lithium isotopes are highly sensitive to EEP anomalies.

Using unstable isotopes can enhance EEP test sensitivity.

Abstract

We review the physics of atoms and clocks in weakly curved spacetime, and how each may be used to test the Einstein Equivalence Principle (EEP) in the context of the minimal Standard Model Extension (mSME). We find that conventional clocks and matter-wave interferometers are sensitive to the same kinds of EEP-violating physics. We show that the analogy between matter-waves and clocks remains true for systems beyond the semiclassical limit. We quantitatively compare the experimentally observable signals for EEP violation in matter-wave experiments. We find that comparisons of $^{6}$Li and $^{7}$Li are particularly sensitive to such anomalies. Tests involving unstable isotopes, for which matter-wave interferometers are well suited, may further improve the sensitivity of EEP tests.