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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.

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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.

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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.

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Correspondence to Jeff Steinhauer.

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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

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