Integrated Mach–Zehnder interferometer forBose–Einstein condensates

摘要

Particle-wave duality enables the construction of interferometers for matter waves, whichcomplement optical interferometers in precision measurement devices. This requires thedevelopment of atom-optics analogues to beam splitters, phase shifters and recombiners.Integrating these elements into a single device has been a long-standing goal. Here wedemonstrate a full Mach–Zehnder sequence with trapped Bose–Einstein condensatesconfined on an atom chip. Particle interactions in our Bose–Einstein condensate matter waveslead to a nonlinearity, absent in photon optics. We exploit it to generate a non-classical statehaving reduced number fluctuations inside the interferometer. Making use of spatiallyseparated wave packets, a controlled phase shift is applied and read out by a non-adiabaticmatter-wave recombiner. We demonstrate coherence times a factor of three beyond what isexpected for coherent states, highlighting the potential of entanglement as a resource formetrology. Our results pave the way for integrated quantum-enhanced matter-wave sensors.