Progress towards a spin-squeezed dual-species atom interferometric accelerometer for testing the Equivalence Principle

We present progress towards a terrestrial dual-species atom interferometric accelerometer designed to test the Weak Equivalence Principle (WEP) with high precision. Our scheme utilizes ⁸⁵Rb and ⁸⁷Rb atoms and aims to surpass the standard quantum limit (SQL) by employing a Generalized Echo Squeezing Protocol (GESP) and Large Momentum Transfer (LMT) Bragg pulses. While space-borne implementations of this architecture could eventually reach Eötvös parameter sensitivities of ∼10^-20, our current terrestrial experiment targets ∼10^-15. We report on the design and construction of the experimental apparatus, with a focus on the optical dipole trap and the high-finesse optical squeezing resonator.