Mainz 2026 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 36: Matter Wave Interferometry and Metrology I

Q 36.8: Talk

Wednesday, March 4, 2026, 16:15–16:30, P 11

’Goos-Hänchen’ shifts and tilts in Bragg-Beam splitters with Bose-Einstein condensate — •Abhay Mishra, Adam Abdalla, Oleksandr V. Marchukov, and Reinhold Walser — Institute of Applied Physics, Technical University Darmstadt, Hochschulstr 4a, D-64289, Darmstadt, Germany

The wave optical phenomena of shifts and tilts of finite sized beam interacting with an interface was experimentally proven by F. Goos and H. Hänchen, now collectively known as Goos-Hänchen (GH) effect [1]. This lateral shift of beam was also observed before by Newton [2].

Our work here shows GH shifts in position and momenta of reflected Bose-Einstein condensate (BEC) wavelets emerging from Bragg-beam splitter.These effects become particularly important for precision measurements in long-time atom interferometry, where it can accumulate and result in loss of coherence. Using an analytical picture of superimposing Gaussian wavelets ansatz, we have quantified GH shifts of wavepackets from the expected classical trajectory. It matches with our numerical results of (3+1)D Gross-Pitaeviskii simulations and, significant for QUANTUS collaboration (DLR, grant number 50WM2450E) and broader matter-wave community.

[1] F. Goos and H. Hänchen, Ann. Phys. (Leipzig) 436, 333 (1947).

[2] I. Newton, Opticks, or, A Treatise of the Reflections, Refractions, Inflections and Colours of Light (Prometheus Books, New York, 2003), 4th ed.

[3] McKay, Samuel, et al. Physical Review Letters 134(9),093803 (2025).

Keywords: Goos-H\"anchen; atom interferometry; Bose-Einstein condensates; Bragg-beam splitter; QUANTUS