Superradiant instability of the Kerr brane
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Superradiant instability of the Kerr brane. / Ishibashi, Akihiro; Pani, Paolo; Gualtieri, Leonardo; Cardoso, Vitor.
I: Journal of High Energy Physics, Bind 2015, Nr. 9, 209, 29.09.2015.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Superradiant instability of the Kerr brane
AU - Ishibashi, Akihiro
AU - Pani, Paolo
AU - Gualtieri, Leonardo
AU - Cardoso, Vitor
PY - 2015/9/29
Y1 - 2015/9/29
N2 - We consider linear gravitational perturbations of the Kerr brane, an exact solution of vacuum Einstein's equations in dimensions higher than four and a low-energy solution of string theory. Decomposing the perturbations in tensor harmonics of the trans-verse Ricci-flat space, we show that tensor- and vector-type metric perturbations of the Kerr brane satisfy respectively a massive Klein-Gordon equation and a Proca equation on the four-dimensional Kerr space, where the mass term is proportional to the eigenvalue of the harmonics. Massive bosonic fields trigger a well-known superradiant instability on a Kerr black hole. We thus establish that Kerr branes in dimensions D a parts per thousand yen 6 are gravi-tationally unstable due to superradiance. These solutions are also unstable against the Gregory-Laflamme instability and we discuss the conditions for either instability to occur and their rather different nature. When the transverse dimensions are compactified and much smaller than the Kerr horizon, only the superradiant instability is present, with a time scale much longer than the dynamical time scale. Our formalism can be also used to discuss other types of higher-dimensional black objects, taking advantage of recent progress in studying linear perturbations of four-dimensional black holes.
AB - We consider linear gravitational perturbations of the Kerr brane, an exact solution of vacuum Einstein's equations in dimensions higher than four and a low-energy solution of string theory. Decomposing the perturbations in tensor harmonics of the trans-verse Ricci-flat space, we show that tensor- and vector-type metric perturbations of the Kerr brane satisfy respectively a massive Klein-Gordon equation and a Proca equation on the four-dimensional Kerr space, where the mass term is proportional to the eigenvalue of the harmonics. Massive bosonic fields trigger a well-known superradiant instability on a Kerr black hole. We thus establish that Kerr branes in dimensions D a parts per thousand yen 6 are gravi-tationally unstable due to superradiance. These solutions are also unstable against the Gregory-Laflamme instability and we discuss the conditions for either instability to occur and their rather different nature. When the transverse dimensions are compactified and much smaller than the Kerr horizon, only the superradiant instability is present, with a time scale much longer than the dynamical time scale. Our formalism can be also used to discuss other types of higher-dimensional black objects, taking advantage of recent progress in studying linear perturbations of four-dimensional black holes.
KW - Classical Theories of Gravity
KW - Black Holes
KW - Black Holes in String Theory
KW - BLACK-HOLE
KW - PERTURBATIONS
KW - STRINGS
KW - DIMENSIONS
KW - EQUATION
U2 - 10.1007/JHEP09(2015)209
DO - 10.1007/JHEP09(2015)209
M3 - Journal article
VL - 2015
JO - Journal of High Energy Physics (Online)
JF - Journal of High Energy Physics (Online)
SN - 1126-6708
IS - 9
M1 - 209
ER -
ID: 300072682