Erlangen 2018 – scientific program
Q 31.6: Talk
Tuesday, March 6, 2018, 15:15–15:30, K 1.013
Plasma vs Drude modelling of the Casimir force: beyond the proximity force approximation — •Michael Hartmann1, Gert-Ludwig Ingold1, and Paulo A. Maia Neto2 — 1Universität Augsburg, Institut für Physik, 86135 Augsburg — 2Instituto de Física, UFRJ, Rio de Janeiro, Brazil
We calculate the Casimir force and its gradient between a spherical and a planar gold surface . Significant numerical improvements allow us to extend the range of accessible parameters into the experimental regime. We compare our numerically exact results with those obtained within the proximity force approximation (PFA) employed in the analysis of all Casimir force experiments reported in the literature so far. Special attention is paid to the difference between the Drude model and the dissipationless plasma model at zero frequency. It is found that the correction to PFA is too small to explain the discrepancy between the experimental data and the PFA result based on the Drude model. However, it turns out that for the plasma model, the corrections to PFA lie well outside the experimental bound obtained by probing the variation of the force gradient with the sphere radius . The corresponding corrections based on the Drude model are significantly smaller but still in violation of the experimental bound for small distances between plane and sphere.
 M. Hartmann et al., Phys. Rev. Lett. 119, 043901 (2017)
 D. E. Krause et al., Phys. Rev. Lett. 98, 050403 (2007)