Stable Casimir equilibria and quantum trapping
Something repulsive in the Casimir effect
Two uncharged objects (metal plates for instance) will experience an attractive force between them, the magnitude of which increases as they are brought closer together. This force, or Casimir effect, is caused by vacuum fluctuations of the electromagnetic field. Effectively, more modes outside than between the objects results in the objects being pushed together. Zhao et al. show that the extent of the electromagnetic fluctuations can be controlled by coating one of the objects with a dielectric (Teflon), which changes the Casimir effect to a repulsive force at small distances. This then cancels out the force between plates and produces a point of stable equilibrium.
Science, this issue p. 984
Abstract
The Casimir interaction between two parallel metal plates in close proximity is usually thought of as an attractive interaction. By coating one object with a low–refractive index thin film, we show that the Casimir interaction between two objects of the same material can be reversed at short distances and preserved at long distances so that two objects can remain without contact at a specific distance. With such a stable Casimir equilibrium, we experimentally demonstrate passive Casimir trapping of an object in the vicinity of another at the nanometer scale, without requiring any external energy input. This stable Casimir equilibrium and quantum trapping can be used as a platform for a variety of applications such as contact-free nanomachines, ultrasensitive force sensors, and nanoscale manipulations.
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Supplementary Material
Summary
Materials and Methods
Figs. S1 to S10
Table S1
Movie S1
Resources
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Information & Authors
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Published In
Science
Volume 364 | Issue 6444
7 June 2019
7 June 2019
Copyright
Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
This is an article distributed under the terms of the Science Journals Default License.
Submission history
Received: 20 February 2019
Accepted: 17 May 2019
Published in print: 7 June 2019
Acknowledgments
R.Z. thanks J. Pendry for helpful theoretical discussion at Imperial College London before he joined UC Berkeley. Funding: This work was primarily supported by the U.S. Office of Naval Research (ONR) MURI program (grant N00014-17-1-2588), the King Abdullah University of Science and Technology Office of Sponsored Research (OSR) (award OSR-2016-CRG5-2950-03), and the Gordon and Betty Moore Foundation. We also acknowledge the AFM user facility at the Molecular Foundry, supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (contract DE-AC02-05CH11231). Author contributions: R.Z., S.Y., and X.Z. conceived the project. R.Z. performed theoretical investigations. R.Z., L.L., S.Y., and W.B. designed the trapping experiments. R.Z., L.L., and S.Y. performed the trapping measurements. R.Z., L.L., S.Y., and W.B. fabricated the samples. S.Y. performed the zeta potential measurement. W.B. and Y.X. performed AFM measurements with assistance from P.A. All authors contributed to manuscript preparation and discussion. X.Z. and Y.W. guided the research. Competing interests: The authors declare no competing interests. Data and materials availability: All data are available in the manuscript or the supplementary materials.
Authors
Funding Information
Office of Naval Research: N00014-13-1-0649
the King Abdullah University of Science and Technology Office of Sponsored Research: OSR- 2016-CRG5-2950-03
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