Observation of the thermal casimir force

ABSTRACT Quantum theory predicts the existence of the Casimir force between macroscopic bodies, a force arising from the zero-point energy of electromagnetic field modes around them. A

thermal Casimir force, due to thermal rather than quantum fluctuations of the electromagnetic field at finite temperature, was theoretically predicted long ago. Here we report the

experimental observation of the thermal Casimir force between two gold plates. We measured the attractive force between a flat and a spherical plate for separations between 0.7 μm and 7 μm.

An electrostatic force caused by potential patches on the plates’ surfaces is included in the analysis. Previous measurements of the quantum-fluctuation-induced force have been unable to

clearly settle the question of whether the correct low-frequency form of the dielectric constant dispersion for calculating Casimir forces is the Drude model or the plasma model. Our

experimental results are in excellent agreement (reduced _χ_2 of 1.04) with the Casimir force calculated using the Drude model, including the _T_=300 K thermal force, which dominates over

the quantum fluctuation-induced force at separations greater than 3 μm. The plasma model result is excluded in the measured separation range. Access through your institution Buy or subscribe

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RADIATIVE LOSS OF COHERENCE IN FREE ELECTRONS: A LONG-RANGE QUANTUM PHENOMENON Article Open access 26 January 2024 FINGERPRINTS OF NONEQUILIBRIUM STATIONARY DISTRIBUTIONS IN DISPERSION

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of Solids_ (Academic, 1998). Download references ACKNOWLEDGEMENTS The authors thank V. Yashchuk for performing the surface roughness measurements, and acknowledge discussions with S. Eckel

and F. Intravaia. This work was supported by the DARPA/MTOs Casimir Effect Enhancement project under SPAWAR Contract No. N66001-09-1-2071. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS *

Department of Physics, Yale University, New Haven, Connecticut 06520-8120, PO Box 208120, USA A. O. Sushkov & S. K. Lamoreaux * Department of Physics, Seattle University, 901 12th

Avenue, Seattle, Washington 98122, USA W. J. Kim * Theoretical Division MS B213, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA D. A. R. Dalvit Authors * A. O. Sushkov

View author publications You can also search for this author inPubMed Google Scholar * W. J. Kim View author publications You can also search for this author inPubMed Google Scholar * D. A.

R. Dalvit View author publications You can also search for this author inPubMed Google Scholar * S. K. Lamoreaux View author publications You can also search for this author inPubMed Google

Scholar CONTRIBUTIONS A.O.S. performed data analysis and prepared the manuscript. W.J.K. carried out optical property measurements, theoretical force calculations, and programming for data

acquisition. D.A.R.D. provided theoretical support and calculations. S.K.L. performed data acquisition, programming and calibrations. CORRESPONDING AUTHOR Correspondence to A. O. Sushkov.

ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Sushkov,

A., Kim, W., Dalvit, D. _et al._ Observation of the thermal Casimir force. _Nature Phys_ 7, 230–233 (2011). https://doi.org/10.1038/nphys1909 Download citation * Received: 17 September 2010

* Accepted: 17 December 2010 * Published: 06 February 2011 * Issue Date: March 2011 * DOI: https://doi.org/10.1038/nphys1909 SHARE THIS ARTICLE Anyone you share the following link with will

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