Complex orientation dependence of Casimir-Polder interaction induced by curvature and optical properties of the surface and the surrounding medium
Phys. Rev. B 112, 205405 – Published 7 November, 2025
DOI: https://doi.org/10.1103/t5t5-kc9j
Abstract
We employ a multiple scattering expansion to systematically derive curvature corrections to the Casimir-Polder (CP) interaction between small anisotropic particles and general magnetodielectric surfaces. Our results, validated against exact solutions, reveal a complex, distance-dependent interplay between material properties and surface curvature in determining stable particle orientations. We demonstrate that even small surface curvature can induce or eliminate switches in the preferred orientation, a quantum effect that is diminished by thermal fluctuations. This work provides a crucial understanding of how to engineer nanoparticle orientation through tuneable parameters, offering significant implications for micro- and nanomechanical device design.
