Casimir Sign Reversal from Finite-Range Bogoliubov Fluctuations

Abstract:We study the zero-temperature Casimir effect of a three-dimensional Bose fluid with finite-range corrections to its Bogoliubov spectrum. Beyond the universal acoustic contribution scaling as $L^{-3}$, the long-distance expansion contains a nonuniversal $L^{-5}$ correction that can compete with the phononic term. We derive this crossover analytically within a minimal isotropic finite-range model and test the asymptotic result against the full dispersion. A regulator-independent Poisson-resummed calculation confirms that sign reversals of the Casimir energy are possible, while showing that the apparent low-coupling zero inferred by balancing only the $L^{-3}$ and $L^{-5}$ terms is not quantitatively controlled. Robust sign changes instead occur in the stable regime close to roton softening, where the Casimir energy acquires an oscillatory finite-momentum contribution. Strongly dipolar atomic gases provide a natural motivation for microscopic interaction lengths in the nanometric regime. We further discuss how the resulting nonlinear force law could be probed through the frequency response of a driven nanomechanical resonator.

Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Theory (hep-th); Quantum Physics (quant-ph)

arXiv:2610.20897 [cond-mat.quant-gas]

(or arXiv:2610.20897v1 [cond-mat.quant-gas] for this version)

https://doi.org/10.48550/arXiv.2610.20897 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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