Abstract
Casimir forces between surfaces immersed in bromobenzene have recently been measured by Munday et al. [Nature (London) 454, 07610 (2009)]. Attractive Casimir forces were found between gold surfaces. The forces were repulsive between gold and silica surfaces. We show the repulsion is due to retardation effects. The van der Waals interaction is attractive at all separations. The retardation-driven repulsion sets in at around 3 nm. To our knowledge, retardation effects have never been found at such a small distance before. Retardation effects are usually associated with large distances.
- Received 21 October 2011
DOI:https://doi.org/10.1103/PhysRevA.85.010701
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