Squeezed Matter-Wave Interferometer and Momentum Exchange Interaction in a High-Finesse Cavity

An entanglement-enhanced matter-wave interferometer is demonstrated in a high-finessecavity with 1.7 −0.5 +0.5 dB directly observed phase resolution below the standard quantum limit. By exploiting the interaction between matter-wave and cavity, we also demonstrate a cavity-medicated momentum exchange interaction.