Matter-wave optics is often viewed as a linear analogue of photonics, where noninteracting particles are coherently split, diffracted, and recombined, and interference arises from single-particle coherence. In ultracold quantum gases, however, interactions are intrinsic and can rival or exceed kinetic and optical energy scales. This drives matter-wave optics into a nonlinear regime: diffraction and momentum distributions become interaction-dependent, interference contrast degrades or collapses, and revival dynamics appear. In the mean time, interactions can generate squeezing and entanglement, enabling sensitivities beyond the standard quantum limit. We showcase representative examples—covering diffraction, splitting, and interferometry—that illustrate how interactions reshape the basic elements of matter-wave optics and open new opportunities for nonlinear quantum technologies.
Wu et al. (Fri,) studied this question.