Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Observation of quantum Hawking radiation and its entanglement in an analogue black hole

Abstract

We observe spontaneous Hawking radiation, stimulated by quantum vacuum fluctuations, emanating from an analogue black hole in an atomic Bose–Einstein condensate. Correlations are observed between the Hawking particles outside the black hole and the partner particles inside. These correlations indicate an approximately thermal distribution of Hawking radiation. We find that the high-energy pairs are entangled, while the low-energy pairs are not, within the reasonable assumption that excitations with different frequencies are not correlated. The entanglement verifies the quantum nature of the Hawking radiation. The results are consistent with a driven oscillation experiment and a numerical simulation.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Hawking radiation and entanglement in the gravitational analogy.
Figure 2: The analogue black hole.
Figure 3: Oscillating horizon experiment.
Figure 4: Observation of Hawking/partner pairs.
Figure 5: The measured population of the Hawking radiation.
Figure 6: Observation of entanglement between the Hawking pairs.

References

  1. Bekenstein, J. D. Black holes and entropy. Phys. Rev. D 7, 2333–2346 (1973).

    Article  ADS  MathSciNet  Google Scholar 

  2. Hawking, S. W. Black hole explosions? Nature 248, 30–31 (1974).

    Article  ADS  Google Scholar 

  3. Hawking, S. W. Particle creation by black holes. Commun. Math. Phys. 43, 199–220 (1975).

    Article  ADS  MathSciNet  Google Scholar 

  4. Hawking, S. W. Breakdown of predictability in gravitational collapse. Phys. Rev. D 14, 2460–2473 (1976).

    ADS  MathSciNet  Google Scholar 

  5. Susskind, L. The paradox of quantum black holes. Nature Phys. 2, 665–677 (2006).

    Article  ADS  Google Scholar 

  6. Almheiri, A., Marolf, D., Polchinski, J. & Sully, J. Black holes: complementarity or firewalls? J. High Energy Phys. 2013, 62 (2013).

    Article  MathSciNet  Google Scholar 

  7. Unruh, W. G. Experimental black-hole evaporation? Phys. Rev. Lett. 46, 1351–1353 (1981).

    Article  ADS  Google Scholar 

  8. Garay, L. J., Anglin, J. R., Cirac, J. I. & Zoller, P. Sonic analog of gravitational black holes in Bose–Einstein condensates. Phys. Rev. Lett. 85, 4643–4647 (2000).

    Article  ADS  Google Scholar 

  9. Balbinot, R., Fabbri, A., Fagnocchi, S., Recati, A. & Carusotto, I. Nonlocal density correlations as a signature of Hawking radiation from acoustic black holes. Phys. Rev. A 78, 021603(R) (2008).

    Article  ADS  Google Scholar 

  10. Carusotto, I., Fagnocchi, S., Recati, A., Balbinot, R. & Fabbri, A. Numerical observation of Hawking radiation from acoustic black holes in atomic Bose–Einstein condensates. New J. Phys. 10, 103001 (2008).

    Article  ADS  Google Scholar 

  11. Macher, J. & Parentani, R. Black-hole radiation in Bose–Einstein condensates. Phys. Rev. A 80, 043601 (2009).

    Article  ADS  Google Scholar 

  12. Larré, P.-É., Recati, A., Carusotto, I. & Pavloff, N. Quantum fluctuations around black hole horizons in Bose–Einstein condensates. Phys. Rev. A 85, 013621 (2012).

    Article  ADS  Google Scholar 

  13. Recati, A., Pavloff, N. & Carusotto, I. Bogoliubov theory of acoustic Hawking radiation in Bose–Einstein condensates. Phys. Rev. A 80, 043603 (2009).

    Article  ADS  Google Scholar 

  14. Barceló, C., Liberati, S. & Visser, M. Analogue gravity from Bose–Einstein condensates. Class. Quantum Gravity 18, 1137–1156 (2001).

    Article  ADS  MathSciNet  Google Scholar 

  15. Corley, S. & Jacobson, T. Black hole lasers. Phys. Rev. D 59, 124011 (1999).

    Article  ADS  MathSciNet  Google Scholar 

  16. Jacobson, T. A. & Volovik, G. E. Event horizons and ergoregions in 3He. Phys. Rev. D 58, 064021 (1998).

    Article  ADS  Google Scholar 

  17. Schützhold, R. & Unruh, W. G. Hawking radiation in an electromagnetic waveguide? Phys. Rev. Lett. 95, 031301 (2005).

    Article  ADS  Google Scholar 

  18. Giovanazzi, S. Hawking radiation in sonic black holes. Phys. Rev. Lett. 94, 061302 (2005).

    Article  ADS  MathSciNet  Google Scholar 

  19. Horstmann, B., Reznik, B., Fagnocchi, S. & Cirac, J. I. Hawking radiation from an acoustic black hole on an ion ring. Phys. Rev. Lett. 104, 250403 (2010).

    Article  ADS  Google Scholar 

  20. Elazar, M., Fleurov, V. & Bar-Ad, S. All-optical event horizon in an optical analog of a Laval nozzle. Phys. Rev. A 86, 063821 (2012).

    Article  ADS  Google Scholar 

  21. Solnyshkov, D. D., Flayac, H. & Malpuech, G. Black holes and wormholes in spinor polariton condensates. Phys. Rev. B 84, 233405 (2011).

    Article  ADS  Google Scholar 

  22. Busch, X. & Parentani, R. Quantum entanglement in analogue Hawking radiation: When is the final state nonseparable? Phys. Rev. D 89, 105024 (2014).

    Article  ADS  Google Scholar 

  23. Finazzi, S. & Carusotto, I. Entangled phonons in atomic Bose–Einstein condensates. Phys. Rev. A 90, 033607 (2014).

    Article  ADS  Google Scholar 

  24. Steinhauer, J. Measuring the entanglement of analogue Hawking radiation by the density–density correlation function. Phys. Rev. D 92, 024043 (2015).

    Article  ADS  Google Scholar 

  25. de Nova, J. R. M., Sols, F. & Zapata, I. Violation of Cauchy–Schwarz inequalities by spontaneous Hawking radiation in resonant boson structures. Phys. Rev. A 89, 043808 (2014).

    Article  ADS  Google Scholar 

  26. Doukas, J., Adesso, G. & Fuentes, I. Ruling out stray thermal radiation in analogue black holes. Preprint at http://arXiv.org/abs/1404.4324 (2014).

  27. Boiron, D. et al. Quantum signature of analog Hawking radiation in momentum space. Phys. Rev. Lett. 115, 025301 (2015).

    Article  ADS  Google Scholar 

  28. de Nova, J. R. M., Sols, F. & Zapata, I. Entanglement and violation of classical inequalities in the Hawking radiation of flowing atom condensates. New J. Phys. 17, 105003 (2015).

    Article  ADS  Google Scholar 

  29. Lahav, O. et al. Realization of a sonic black hole analog in a Bose–Einstein condensate. Phys. Rev. Lett. 105, 240401 (2010).

    Article  ADS  Google Scholar 

  30. Shammass, I., Rinott, S., Berkovitz, A., Schley, R. & Steinhauer, J. Phonon dispersion relation of an atomic Bose–Einstein condensate. Phys. Rev. Lett. 109, 195301 (2012).

    Article  ADS  Google Scholar 

  31. Schley, R. et al. Planck Distribution of Phonons in a Bose–Einstein Condensate. Phys. Rev. Lett. 111, 055301 (2013).

    Article  ADS  Google Scholar 

  32. Steinhauer, J. Observation of self-amplifying Hawking radiation in an analogue black-hole laser. Nature Phys. 10, 864–869 (2014).

    Article  ADS  Google Scholar 

  33. Philbin, T. G. et al. Fiber-optical analog of the event horizon. Science 319, 1367–1370 (2008).

    Article  ADS  Google Scholar 

  34. Belgiorno, F. et al. Hawking radiation from ultrashort laser pulse filaments. Phys. Rev. Lett. 105, 203901 (2010).

    Article  ADS  Google Scholar 

  35. Unruh, W. & Schützhold, R. Hawking radiation from ‘phase horizons’ in laser filaments? Phys. Rev. D 86, 064006 (2012).

    Article  ADS  Google Scholar 

  36. Liberati, S., Prain, A. & Visser, M. Quantum vacuum radiation in optical glass. Phys. Rev. D 85, 084014 (2012).

    Article  ADS  Google Scholar 

  37. Nguyen, H. S. et al. Acoustic black hole in a stationary hydrodynamic flow of microcavity polaritons. Phys. Rev. Lett. 114, 036402 (2015).

    Article  ADS  Google Scholar 

  38. Weinfurtner, S., Tedford, E. W., Penrice, M. C. J., Unruh, W. G. & Lawrence, G. A. Measurement of stimulated Hawking emission in an analogue system. Phys. Rev. Lett. 106, 021302 (2011).

    Article  ADS  Google Scholar 

  39. Rousseaux, G., Mathis, C., Maïssa, P., Philbin, T. G. & Leonhardt, U. Observation of negative-frequency waves in a water tank: a classical analogue to the Hawking effect? New J. Phys. 10, 053015 (2008).

    Article  ADS  Google Scholar 

  40. Parentani, R. From vacuum fluctuations across an event horizon to long distance correlations. Phys. Rev. D 82, 025008 (2010).

    Article  ADS  Google Scholar 

  41. Pines, D. & Nozières, Ph. The Theory of Quantum Liquids Vol. I, Section 2.1 (Addison-Wesley, 1988).

    MATH  Google Scholar 

  42. Nozières, Ph. & Pines, D. The Theory of Quantum Liquids Vol. II, Section 3.1 (Addison-Wesley, 1990).

    MATH  Google Scholar 

  43. Pitaevskii, L. & Stringari, S. Bose–Einstein Condensation Section 12.9 (Oxford Univ. Press, 2003).

    MATH  Google Scholar 

Download references

Acknowledgements

I thank R. Parentani, W. Unruh, F. Michel, N. Pavloff and A. Fabbri for helpful comments. This work was supported by the Israel Science Foundation.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jeff Steinhauer.

Ethics declarations

Competing interests

The author declares no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Steinhauer, J. Observation of quantum Hawking radiation and its entanglement in an analogue black hole. Nature Phys 12, 959–965 (2016). https://doi.org/10.1038/nphys3863

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nphys3863

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing