Multi-path Landau-Zener-Stuckelberg Interferometry with Bose-Einstein Condensates in a Vertical Optical Lattice*

We report on a demonstration of an in-lattice interferometer using multi-path Landau-Zener-Stuckelberg (MPLZS) interference effects in ultracold atoms. We use a {^174}Yb Bose-Einstein Condensate subjected to a vertical lattice made of two counter-propagating laser beams with a tunable frequency difference.  The resulting periodic modulations and resonances in band populations as a function of the Bloch oscillation (BO) period is attributed to coherent splitting of the atomic wavefunction at each encountered avoided crossing of bands, where either a BO or a Landau-Zener (LZ) tunneling event is possible.  While earlier work studied 2-path LZS interferometry with two avoided crossings [1,2], our work extends to multi-path (2^(N-1)) geometries with N up to 10. We also model diabatic losses at large lattice depths where the LZ formula breaks down using a single particle model which agrees with the experimental results. Our observations can inform the choice of atom optics used in atom interferometric sensors and expands on our earlier work applying a quantum transport approach to precision atom interferometry [3,4]. 

[1] S. Kling et al, Phys Rev Lett 105, 215301 (2010) 

[2] A. Zenesini et al Phys Rev A 82, 065601 (2010)

[3] D. Gochnauer et al, Phys Rev A 100, 043611 (2019).

[4] K. McAlpine et al, Phys. Rev. A 101, 023614 (2020)