Entanglement-enhanced interferometry using single-atom resolved Twin-Fock states in 87Rb BECs

Abstract

Atom interferometers are among the most sensitive tools in quantum metrology but are typically limited by the standard quantum limit (SQL). Entangled input states can surpass this bound and approach Heisenberg scaling. We present a metrology-ready 87Rb platform that combines sub-500 ms Bose-Einstein condensate (BEC) production in time-averaged optical potentials with state-resolved, single-atom-resolved detection. We create high-fidelity Twin-Fock states via spin-changing collisions and observe Hong-Ou-Mandel-type atomic interference of up to 10 atoms. Using these states' near-perfect number correlations for heralding, interferometry can be perfomed with large Dicke states for sub-SQL metrology at total atom numbers of 1000 and beyond.