Multi-path Landau-Zener-Stuckelberg Interferometry with Bose-Einstein Condensates in Optical Lattices

We report on multi-path Landau-Zener-Stuckelberg (MPLZS) interference effects in the transport of ultracold atoms in a tilted optical lattice, resulting in periodic modulations and resonances in band populations as a function of tilt. These effects are a result of coherent splitting of the atomic wavefunction at each encountered avoided crossing of bands, where either a Bloch oscillation or a Landau-Zener (LZ) tunneling event is possible. We use a {^174}Yb Bose-Einstein condensate subjected to an accelerating lattice made of two counter-propagating laser beams with tunable frequency difference. 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 100. We also model diabatic losses at large lattice depths where the  LZ formula breaks down. 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]. These investigations can be applied towards a contrast interferometer in a vertical geometry for a precision measurement of the fine-structure constant [5].

[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)

[5] B. Plotkin-Swing et al, Phys Rev Lett 121, 133201 (2018).