Objects at finite temperature emit thermal radiation with an outward energy–momentum flow, which exerts an outward radiation pressure. At room temperature, a caesium atom scatters on average less than one of these blackbody radiation photons every 108 years. Thus, it is generally assumed that any scattering force exerted on atoms by such radiation is negligible. However, atoms also interact coherently with the thermal electromagnetic field. In this work, we measure an attractive force induced by blackbody radiation between a caesium atom and a heated, centimetre-sized cylinder, which is orders of magnitude stronger than the outward-directed radiation pressure. Using atom interferometry, we find that this force scales with the fourth power of the cylinder’s temperature. The force is in good agreement with that predicted from an a.c. Stark shift gradient of the atomic ground state in the thermal radiation field1. This observed force dominates over both gravity and radiation pressure, and does so for a large temperature range.

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  1. 1.

    Sonnleitner, M., Ritsch-Marte, M. & Ritsch, H. Attractive optical forces from blackbody radiation. Phys. Rev. Lett. 111, 23601 (2013).

  2. 2.

    Safronova, M. S. et al. Black-body radiation shifts and theoretical contributions to atomic clock research. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57, 94–105 (2010).

  3. 3.

    Nicholson, T. L. et al. Systematic evaluation of an atomic clock at 2 × 10−18 total uncertainty. Nat. Commun. 6, 6896 (2015).

  4. 4.

    Nichols, E. & Hull, G. Pressure due to light and heat radiation. Astrophys. J. 15, 62 (1902).

  5. 5.

    Lebedev, P. N. & Lazarev, P. P. Die Druckkräfte des Lichtes, zwei Abhandlungen (Engelmann, 1913).

  6. 6.

    Burns, J. A., Lamy, P. L. & Soter, S. Radiation forces on small particles in the solar system. Icarus 40, 1–48 (1979).

  7. 7.

    Shestakova, L. I. Solar radiation pressure as a mechanism of acceleration of atoms and first ions with low ionization potentials. Sol. Syst. Res. 49, 139–145 (2015).

  8. 8.

    Ashkin, A. & Dziedzic, J. M. Optical trapping and manipulation of viruses and bacteria. Science 235, 1517–1520 (1987).

  9. 9.

    Phillips, W. D. Nobel Lecture: Laser cooling and trapping of neutral atoms. Rev. Mod. Phys. 70, 721–741 (1998).

  10. 10.

    Cronin, A. D., Schmiedmayer, J. & Pritchard, D. E. Optics and interferometry with atoms and molecules. Rev. Mod. Phys. 81, 1051–1129 (2009).

  11. 11.

    Hornberger, K., Gerlich, S., Haslinger, P., Nimmrichter, S. & Arndt, M. Colloquium: Quantum interference of clusters and molecules. Rev. Mod. Phys. 84, 157–173 (2012).

  12. 12.

    Aspelmeyer, M., Kippenberg, T. J. & Marquardt, F. Cavity optomechanics. Rev. Mod. Phys. 86, 1391–1452 (2014).

  13. 13.

    Dimopoulos, S., Graham, P., Hogan, J. & Kasevich, M. Testing general relativity with atom interferometry. Phys. Rev. Lett. 98, 111102 (2007).

  14. 14.

    Schlippert, D. et al. Ground tests of Einstein’s equivalence principle: from lab-based to 10-m atomic fountains. Preprint at https://arxiv.org/abs/1507.05820 (2015).

  15. 15.

    Tino, G. M. et al. Precision gravity tests with atom interferometry in space. Nucl. Phys. B Proc. Suppl. 243/244, 203–217 (2013).

  16. 16.

    Hamilton, P. et al. Atom-interferometry constraints on dark energy. Science 349, 849–851 (2015).

  17. 17.

    McGuirk, J. M., Foster, G. T., Fixler, J. B., Snadden, M. J. & Kasevich, M. A. Sensitive absolute-gravity gradiometry using atom interferometry. Phys. Rev. A 65, 33608 (2002).

  18. 18.

    Rosi, G., Sorrentino, F., Cacciapuoti, L., Prevedelli, M. & Tino, G. M. Precision measurement of the Newtonian gravitational constant using cold atoms. Nature 510, 518–521 (2014).

  19. 19.

    Canuel, B. et al. Exploring gravity with the MIGA large scale atom interferometer. Preprint at https://arxiv.org/pdf/1703.02490.pdf (2017).

  20. 20.

    Graham, P. W., Hogan, J. M., Kasevich, M. A. & Rajendran, S. New method for gravitational wave detection with atomic sensors. Phys. Rev. Lett. 110, 171102 (2013).

  21. 21.

    Peters, A., Chung, K. & Chu, S. Measurement of gravitational acceleration by dropping atoms. Nature 400, 849–852 (1999).

  22. 22.

    Hamilton, P. et al. Atom interferometry in an optical cavity. Phys. Rev. Lett. 114, 100405 (2015).

  23. 23.

    Jaffe, M. et al. Testing sub-gravitational forces on atoms from a miniature, in-vacuum source mass. Nat. Phys. 13, 938–942 (2017).

  24. 24.

    Micalizio, S., Godone, A., Calonico, D., Levi, F. & Lorini, L. Blackbody radiation shift of the Cs 133 hyperfine transition frequency. Phys. Rev. A 69, 53401 (2004).

  25. 25.

    Henkel, C., Joulain, K., Mulet, J.-P. & Greffet, J.-J. Radiation forces on small particles in thermal near fields. J. Opt. A Pure Appl. Opt. 4, 356 (2002).

  26. 26.

    Antezza, M., Pitaevskii, L. P. & Stringari, S. New asymptotic behavior of the surface-atom force out of thermal equilibrium. Phys. Rev. Lett. 95, 113202 (2005).

  27. 27.

    Obrecht, J. M. et al. Measurement of the temperature dependence of the Casimir–Polder force. Phys. Rev. Lett. 98, 063201 (2007).

  28. 28.

    Bouchendira, R., Cladé, P., Guellati-Khélifa, S., Nez, F. & Biraben, F. New determination of the fine structure constant and test of the quantum electrodynamics. Phys. Rev. Lett. 106, 80801 (2011).

  29. 29.

    Parker, R. H. et al. Controlling the multiport nature of Bragg diffraction in atom interferometry. Phys. Rev. A 94, 53618 (2016).

  30. 30.

    Hohensee, M., Estey, B., Hamilton, P., Zeilinger, A. & Müller, H. Force-free gravitational redshift: proposed gravitational Aharonov–Bohm experiment. Phys. Rev. Lett. 108, 230404 (2012).

  31. 31.

    Treutlein, P., Chung, K. Y. & Chu, S. High-brightness atom source for atomic fountains. Phys. Rev. A 63, 51401 (2001).

  32. 32.

    Scheel, S. & Buhmann, S. Y. Casimir–Polder forces on moving atoms. Phys. Rev. A 80, 42902 (2009).

  33. 33.

    Siegel, R., Howell, J. R. & Menguc, M. P. Thermal Radiation Heat Transfer 5th edn (CRC Press, 2010).

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We thank Randy Putnam for collaboration in the laboratory and Dennis Rätzel for stimulating discussions. This material is based upon work supported by the David and Lucile Packard Foundation, the National Science Foundation under grant no 037166, the Defense Advanced Research Projects Agency grant no 033504, and the National Aeronautics and Space Administration grants nos 041060-002, 041542, 039088, 038706 and 036803. We also acknowledge collaboration with Honeywell Aerospace under DARPA contract no N66001-12-1-4232. O.S. was supported by HFSP fellowship LT000844/2016-C. M.S. was supported by the ERC Advanced Grant (247024 catchIT) and the Royal Society (RP150122). P.H. and M.S. thank the Austrian Science Fund (FWF): J3680, J3703.

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  1. Department of Physics, University of California–Berkeley, Berkeley, CA, USA

    • Philipp Haslinger
    • , Matt Jaffe
    • , Victoria Xu
    • , Osip Schwartz
    •  & Holger Müller
  2. Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

    • Osip Schwartz
    •  & Holger Müller
  3. School of Physics and Astronomy, University of Glasgow, Glasgow, UK

    • Matthias Sonnleitner
  4. Division for Biomedical Physics, Medical University of Innsbruck, Innsbruck, Austria

    • Monika Ritsch-Marte
  5. Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria

    • Helmut Ritsch


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P.H., M.J., V.X., O.S. and H.M. designed the experiment, made the measurements and carried out the data analysis. M.S., M.R.M. and H.R. carried out numerical simulations of the blackbody force. All authors contributed to the manuscript.

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The authors declare no competing financial interests.

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Correspondence to Holger Müller.

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