Measuring the Casimir force gradient from graphene on a SiO_2 substrate

TL;DR

This study measures how graphene affects the Casimir force gradient on a SiO2 substrate, finding a measurable increase consistent with theoretical predictions, using a dynamic atomic force microscope.

Contribution

First experimental measurement of the Casimir force gradient involving graphene on a SiO2 substrate with results aligning with Dirac model predictions.

Findings

Graphene increases the Casimir force gradient by up to 9%.

Experimental results agree qualitatively with additive theoretical models.

The measurement technique demonstrates high sensitivity to graphene's influence.

Abstract

The gradient of the Casimir force between a Si-SiO${}_2$-graphene substrate and an Au-coated sphere is measured by means of a dynamic atomic force microscope operated in the frequency shift technique. It is shown that the presence of graphene leads to up to 9% increase in the force gradient at the shortest separation considered. This is in qualitative agreement with the predictions of an additive theory using the Dirac model of graphene.