Casimir Sign Reversal from Finite-Range Bogoliubov Fluctuations
The study investigated zero-temperature Casimir effects for a 3D Bose fluid with finite-range corrections to its spectrum. While simple expansions suggested a low-coupling zero, full calculations revealed genuine sign reversals in the stable regime near roton softening due to finite-momentum contributions. This indicates that nonuniversal interactions can lead to oscillatory Casimir forces.