Article | Published:

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

Nature Physics volume 12, pages 959965 (2016) | Download Citation

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.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

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

  2. 2.

    Black hole explosions? Nature 248, 30–31 (1974).

  3. 3.

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

  4. 4.

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

  5. 5.

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

  6. 6.

    , , & Black holes: complementarity or firewalls? J. High Energy Phys. 2013, 62 (2013).

  7. 7.

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

  8. 8.

    , , & Sonic analog of gravitational black holes in Bose–Einstein condensates. Phys. Rev. Lett. 85, 4643–4647 (2000).

  9. 9.

    , , , & Nonlocal density correlations as a signature of Hawking radiation from acoustic black holes. Phys. Rev. A 78, 021603(R) (2008).

  10. 10.

    , , , & Numerical observation of Hawking radiation from acoustic black holes in atomic Bose–Einstein condensates. New J. Phys. 10, 103001 (2008).

  11. 11.

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

  12. 12.

    , , & Quantum fluctuations around black hole horizons in Bose–Einstein condensates. Phys. Rev. A 85, 013621 (2012).

  13. 13.

    , & Bogoliubov theory of acoustic Hawking radiation in Bose–Einstein condensates. Phys. Rev. A 80, 043603 (2009).

  14. 14.

    , & Analogue gravity from Bose–Einstein condensates. Class. Quantum Gravity 18, 1137–1156 (2001).

  15. 15.

    & Black hole lasers. Phys. Rev. D 59, 124011 (1999).

  16. 16.

    & Event horizons and ergoregions in 3He. Phys. Rev. D 58, 064021 (1998).

  17. 17.

    & Hawking radiation in an electromagnetic waveguide? Phys. Rev. Lett. 95, 031301 (2005).

  18. 18.

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

  19. 19.

    , , & Hawking radiation from an acoustic black hole on an ion ring. Phys. Rev. Lett. 104, 250403 (2010).

  20. 20.

    , & All-optical event horizon in an optical analog of a Laval nozzle. Phys. Rev. A 86, 063821 (2012).

  21. 21.

    , & Black holes and wormholes in spinor polariton condensates. Phys. Rev. B 84, 233405 (2011).

  22. 22.

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

  23. 23.

    & Entangled phonons in atomic Bose–Einstein condensates. Phys. Rev. A 90, 033607 (2014).

  24. 24.

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

  25. 25.

    , & Violation of Cauchy–Schwarz inequalities by spontaneous Hawking radiation in resonant boson structures. Phys. Rev. A 89, 043808 (2014).

  26. 26.

    , & Ruling out stray thermal radiation in analogue black holes. Preprint at (2014).

  27. 27.

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

  28. 28.

    , & Entanglement and violation of classical inequalities in the Hawking radiation of flowing atom condensates. New J. Phys. 17, 105003 (2015).

  29. 29.

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

  30. 30.

    , , , & Phonon dispersion relation of an atomic Bose–Einstein condensate. Phys. Rev. Lett. 109, 195301 (2012).

  31. 31.

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

  32. 32.

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

  33. 33.

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

  34. 34.

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

  35. 35.

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

  36. 36.

    , & Quantum vacuum radiation in optical glass. Phys. Rev. D 85, 084014 (2012).

  37. 37.

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

  38. 38.

    , , , & Measurement of stimulated Hawking emission in an analogue system. Phys. Rev. Lett. 106, 021302 (2011).

  39. 39.

    , , , & Observation of negative-frequency waves in a water tank: a classical analogue to the Hawking effect? New J. Phys. 10, 053015 (2008).

  40. 40.

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

  41. 41.

    & The Theory of Quantum Liquids Vol. I, Section 2.1 (Addison-Wesley, 1988).

  42. 42.

    & The Theory of Quantum Liquids Vol. II, Section 3.1 (Addison-Wesley, 1990).

  43. 43.

    & Bose–Einstein Condensation Section 12.9 (Oxford Univ. Press, 2003).

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

Affiliations

  1. Department of Physics, Technion—Israel Institute of Technology, Technion City, Haifa 32000, Israel

    • Jeff Steinhauer

Authors

  1. Search for Jeff Steinhauer in:

Competing interests

The author declares no competing financial interests.

Corresponding author

Correspondence to Jeff Steinhauer.

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nphys3863

Further reading