Contributor info: Prof. Michael Köhl

Moritz Breyer, Daniel Eberz, Andreas Kell, Michael Köhl

SciPost Phys. 18, 053 (2025) · published 14 February 2025 | Toggle abstract · pdf

We study the response of a Fermi superfluid to a rapid change of the interaction strength. For a broad range of quench parameters, the order parameter exhibits damped oscillations, however, we also identify quench regimes in which these oscillations are absent. By comparing our data to a numerical model we find that the damping time constants are explainable by a dephasing in a local density approximation, however, the oscillation frequencies, while being comparable to the superconducting order parameter, display in detail significant differences to the integrable BCS (Bardeen-Cooper-Schrieffer) model.

Tobias Kree, Michael Köhl

SciPost Phys. 15, 034 (2023) · published 27 July 2023 | Toggle abstract · pdf

We demonstrate three-dimensional sculpting of laser beams using two-dimensional holograms. Without relying on initial guesses of the analytic properties or the Fourier transform of the desired light field, we show that an improved numerical phase retrieval algorithm can produce continuous three-dimensional intensity distributions of arbitrary shapes. We benchmark our algorithm against optical bottle beams and double-helix beams and then show the extension to complex optical structures.