Opportunities and challenges involving repulsive Casimir forces in nanotechnology
Calum Shelden · Benjamin Spreng · Jeremy N. Munday
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Calum Shelden, Benjamin Spreng and Jeremy Munday of the University of California, Davis survey the whole effort to turn the Casimir force around. The force comes from the electromagnetic field’s own fluctuations, and between two metal surfaces a few hundred nanometres apart it pulls them together. That pull is now an engineering problem: as switches, mirrors and sensors shrink to the scale where the vacuum has a say, the moving parts of micro- and nanoelectromechanical systems stick to their neighbours or collapse onto them. So a real research programme has grown up around making the same force push instead of pull, and this review sorts it into four families — put a liquid between the surfaces, use magnetic materials, drive the system out of thermal equilibrium, or shape the surfaces into special geometries. The authors weigh each on how close it is to a working experiment. The prize they name is a levitating component with almost no friction at all.
Why it matters hereChapter 2 treats the vacuum as a medium whose pressure can be engineered by material design, and repulsion is the cleanest demonstration of that: the same field that pulls can be made to push by changing what it is pushing on. Chapter 6 needs exactly that asymmetry, because every route to drawing useful work from the field starts with surfaces that do not simply snap together.
What it claims
01The Casimir force arises from quantum electrodynamic fluctuations and appears as an attraction between metallic surfaces separated by only hundreds of nanometres.Abstract, Applied Physics Reviews 11, 041325
Settled physics02As device architectures scale down to the nano- and microscale, quantum phenomena exert increasing influence on how those devices behave, and attractive Casimir interactions routinely cause the components of nano- and microelectromechanical systems to adhere to one another or collapse.Abstract, Applied Physics Reviews 11, 041325
Settled physics03Because of that, substantial research effort has gone into manipulating the Casimir force with the specific aim of taking it from attractive to repulsive, and the authors treat that as an established engineering goal rather than a speculation.Abstract, Applied Physics Reviews 11, 041325
Published and peer-reviewed04Four primary strategies have been proposed for engineering a repulsive Casimir force: placing a liquid medium between the surfaces, using magnetic materials, imposing thermodynamic nonequilibrium conditions, and adopting specialised geometries.Abstract, Applied Physics Reviews 11, 041325
Published and peer-reviewed05The payoff the authors name is twofold: repulsion would mitigate component collapse in nanodevices, and it would open the way to quantum levitation and to devices with ultralow friction.Abstract, Applied Physics Reviews 11, 041325
Designed, not yet built06The review’s own contribution is to weigh the four approaches against each other on experimental feasibility and to discuss how each might actually be implemented — which sets the open question as which route reaches a working device first, rather than whether vacuum repulsion is possible at all.Abstract, Applied Physics Reviews 11, 041325
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The way in
https://doi.org/10.1063/5.0218274LICENCE. Published as Applied Physics Reviews, volume 11, issue 4, article 041325, December 2024, by Calum Shelden, Benjamin Spreng and Jeremy N. Munday of the Department of Electrical and Computer Engineering, University of California, Davis. Licence checked directly: Crossref carries no licence statement, and OpenAlex and Unpaywall both report the article closed with no repository copy anywhere, so no text is reproduced here. AUTHORS. The registry record for this sheet had listed a single author; the full three-author list above was taken from the Crossref record on 2026-09-08 and the given names from OpenAlex. SOURCE READ. The publisher’s full text is behind a paywall and the authors have posted no preprint, which was checked against arXiv by title and by author on 2026-09-08. The summary and the claims below are therefore the site’s own, written from the complete author abstract as carried by Crossref, together with the bibliographic record; every locator says Abstract, because that is what was read. The companion primary papers by the same group, which were read in full for their own sheets, are listed at the foot of this page.
How to cite it
Calum Shelden, Benjamin Spreng, Jeremy N. Munday (2024) Opportunities and challenges involving repulsive Casimir forces in nanotechnology. doi:10.1063/5.0218274
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