Atom Chip Diffraction of Bose-Einstein Condensates: The Role of Inter-Atomic Interactions

TL;DR

This paper demonstrates through simulations that inter-atomic interactions significantly influence the diffraction patterns of Bose-Einstein condensates on atom chips, affecting experimental interpretations and device calibrations.

Contribution

It reveals the impact of interactions on diffraction, showing they alter phase evolution and diffraction patterns, which was not fully understood before.

Findings

Interactions broaden and depopulate non-central diffraction orders

Interactions reduce the spatial width of the diffracted cloud

Experiments cannot be fully explained by non-interacting theories

Abstract

We use supercomputer simulations to show that inter-atomic interactions can strongly affect the phase evolution of Bose-Einstein condensates that are diffracted from atom chips, thereby explaining recent experiments. Interactions broaden and depopulate non-central diffraction orders and so, counter-intuitively, they actually reduce the spatial width of the diffracted cloud. This means, more generally, that the experiments cannot be fully described by non-interacting theories and, consequently, interferometers that use many interacting atoms to enhance sensitivity require complex calibration. We identify device geometries required to approximate non-interacting behavior.