Mainz 2026 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 50: Matter Wave Interferometry and Metrology II
Q 50.4: Talk
Thursday, March 5, 2026, 11:45–12:00, P 11
Anomalous tilts and shifts of diffraction orders in Bragg beam-splitters — •Adam Abdalla, Abhay Mishra, Oleksandr Marchukov, and Reinhold Walser — TU Darmstadt, Institute of Applied Physics, Darmstadt, Germany
Interferometric measurements can be used for quantum metrology and inertial sensing or fundamental physics in space [1]. Atomic beam-splitters are integral devices for in three-dimensional matter-wave interferometers. In typical interferometric experiments with Bose-Einstein condensates, one has a superposition of several wavelets (diffraction orders) that extend in the longitudinal x-direction over many optical wavelength λL and are much smaller than the Gaussian laser waist w0≫σy,z in the transversal direction [2].
In this contribution, we analyze the Bragg beam splitting of a decentered BEC in real three-dimensional Gaussian laser beams. We find that a Bragg pulse leads to a spatial displacement (shift) of the diffraction wave packets as well as a correction (tilt) to the Bragg momentum 2kL [3]. This is analogous to the Goos-Hänchen effect in optics [4]. The results are supported by (3+1)D simulations of the Gross-Pitaevskii equation. This results will be relevant for any matter-wave interferometers experiments, for example the QUANTUS Collaboration (DLR, grant number 50WM2450E).
[1] D. Becker, et al., Nature 562, 391 (2018)
[2] A. Neumann, et al., Phys. Rev. A 103, 043306 (2021)
[3] A. D. Ludlow, Yun Je, et al., Rev. Mod. Phys. 87, 637 (2015)
[4] F. Goos and H. Hänchen, Annalen der Physik 436, 333 (1947)
Keywords: Matter-wave interferometers; Bragg beam-splitter; Diffraction wavelets; Bose-Einstein condensates; QUANTUS