Probing many-body effects in harmonic traps with twisted light

JOHANNA FUKS; QUINTEIRO ROSEN, GUILLERMO F.; APPEL, H; P. I. TAMBORENEA

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2023 vol. 107

1098-0121

We explore the potential of twisted light, a structured beam carrying orbital angular momentum, as a tool to unveil many-body effects in parabolically confined systems. According to the Generalized Kohn Theorem, the dipole response of such a multi-particle system to a spatially homogeneous probe is indistinguishable from the response of a system of non-interacting particles. Twisted light however can excite internal degrees of freedom, resulting in the appearance of new peaks in the multipole spectrum which are not present when the probe is a plane wave. We also demonstrate the ability of the proposed twisted light probe to capture the transition of interacting fermions into a strongly correlated regime in a one-dimensional harmonic trap. We report that by suitable choice of the probe?s parameters, the transition into a strongly correlated phase manifests itself as an approaching and ultimate superposition of peaks in the second-order quadrupole response. These features are observed in exact calculations for two electrons, and well reproduced in adiabatic Time-Dependent Density-Functional Theory simulations.