Equivalence Principle and Gravitational Redshift

Understand

We investigate leading order deviations from general relativity that violate the Einstein equivalence principle in the gravitational standard model extension.

• We show that redshift experiments based on matter waves and clock comparisons are equivalent to one another.
• Consideration of torsion balance tests, along with matter wave, microwave, optical, and M\"ossbauer clock tests, yields comprehensive limits on spin-independent Einstein equivalence principle-violating standard model extension terms at the $10^{-6}$ level.