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arXiv · 2609.23609

Casimir force in a water nanolayer confined by graphene sheets

Wijnand Broer·Jure Dobnikar
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Abstract

Casimir forces, arising from quantum and thermal fluctuations, depend strongly on the electromagnetic susceptibilities of the interacting materials. Here, we theoretically investigate the Casimir force between two graphene sheets separated by a nanometer-thin layer of liquid water. We find that, at thicknesses up to 3.4 nm, the confinement reduces the Casimir force by up to 26 % compared to the bulk case. At larger thicknesses, the bulk model underestimates the Casimir force by up to 42 % due to the interface effect. This effect does not decrease monotonically as a function of the layer thickness: it increases up to a maximum at 70 nm and it slowly declines to the bulk limit only at 2 microns. We separately assess the effect of nanoscale confinement on the electronic response of graphene, which has no effect on the Casimir force.

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Wijnand Broer, Jure Dobnikar. 2026-09-20. Casimir force in a water nanolayer confined by graphene sheets. https://arxiv.org/abs/2609.23609

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