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The gravitational Vavilov-Cherenkov effect

Alberto Saa·Marcelo Schiffer
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Abstract

In this essay we show that an uncharged black-hole moving superluminally in a transparent dielectric medium violates Hawking's area theorem. The violation is overcome through the emission of radiation. Since modes cannot emerge from the black hole itself, this radiation must originate from a collective effect in the medium, in complete analogy with the Vavilov-Cherenkov effect. However, because the black-hole is uncharged, the emission mechanism must be different. We discuss the physical origin of the effect and obtain a Newtonian estimative. Then we obtain the appropriate equations in the relativistic case and show that the field which is radiated away is a combination of gravitational and electromagnetic degrees of freedom. Possible astrophysical relevance for the detection of primordial black-holes and binary systems is discussed.

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Alberto Saa, Marcelo Schiffer. 1998-05-20. The gravitational Vavilov-Cherenkov effect. https://doi.org/10.1142/s0217732398001637

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