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Measurement of the Casimir force between dissimilar metals

R. S. Decca·D. López·E. Fischbach·D. E. Krause
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Abstract

The first precise measurement of the Casimir force between dissimilar metals is reported. The attractive force, between a Cu layer evaporated on a microelectromechanical torsional oscillator, and an Au layer deposited on an Al$_2$O$_3$ sphere, was measured dynamically with a noise level of 6 fN/$\sqrt{\rm{Hz}}$. Measurements were performed for separations in the 0.2-2 $μ$m range. The results agree to better than 1% in the 0.2-0.5 $μ$m range with a theoretical model that takes into account the finite conductivity and roughness of the two metals. The observed discrepancies, which are much larger than the experimental precision, can be attributed to a lack of a complete characterization of the optical properties of the specific samples used in the experiment.

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R. S. Decca, D. López, E. Fischbach, D. E. Krause. 2003-07-31. Measurement of the Casimir force between dissimilar metals. https://doi.org/10.1103/physrevlett.91.050402

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