Integrated Mach-Zehnder interferometer for Bose-Einstein condensates

TL;DR

This paper demonstrates an integrated Mach-Zehnder interferometer using trapped Bose-Einstein condensates on an atom chip, exploiting non-linear interactions to generate non-classical states and enhance coherence times for quantum metrology.

Contribution

It presents the first full integrated matter-wave Mach-Zehnder interferometer with BECs, utilizing non-linear interactions to produce non-classical states and extend coherence times.

Findings

Achieved coherence times three times longer than expected for coherent states.

Generated non-classical states with reduced number fluctuations.

Demonstrated potential for quantum-enhanced matter-wave sensors.

Abstract

Particle-wave duality enables the construction of interferometers for matter waves, which complement optical interferometers in precision measurement devices. This requires the development of atom-optics analogs to beam splitters, phase shifters, and recombiners. Integrating these elements into a single device has been a long-standing goal. Here we demonstrate a full Mach-Zehnder sequence with trapped Bose-Einstein condensates (BECs) confined on an atom chip. Particle interactions in our BEC matter waves lead to a non-linearity, absent in photon optics. We exploit it to generate a non-classical state having reduced number fluctuations inside the interferometer. Making use of spatially separated wave packets, a controlled phase 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 for coherent states, highlighting the potential of entanglement as a resource for metrology. Our results pave the way for integrated quantum-enhanced matter-wave sensors.