Integrated Mach-Zehnder interferometer for Bose-Einstein condensates

摘要

Particle-wave duality enables the construction of interferometers for matterwaves, which complement optical interferometers in precision measurementdevices. This requires the development of atom-optics analogs to beamsplitters, phase shifters, and recombiners. Integrating these elements into asingle device has been a long-standing goal. Here we demonstrate a fullMach-Zehnder sequence with trapped Bose-Einstein condensates (BECs) confined onan atom chip. Particle interactions in our BEC matter waves lead to anon-linearity, absent in photon optics. We exploit it to generate anon-classical state having reduced number fluctuations inside theinterferometer. Making use of spatially separated wave packets, a controlledphase shift is applied and read out by a non-adiabatic matter-wave recombiner.We demonstrate coherence times a factor of three beyond what is expected forcoherent states, highlighting the potential of entanglement as a resource formetrology. Our results pave the way for integrated quantum-enhanced matter-wavesensors.