Rapid growth of superradiant instabilities for charged black holes in a cavity

Degollado, Juan Carlos; Herdeiro, Carlos; Rúnarsson, Helgi Freyr

doi:10.1103/physrevd.88.063003

Cited by 117 publications

(125 citation statements)

References 33 publications

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“…The numerical methods employed in this problem are based on the shooting method, which is also called the direct integration (DI) method [31][32][33][34]. It is shown that the DI method is specially suited to find a stationary field configuration with the mirror-like boundary condition.…”

Section: Numerical Procedures and Resultsmentioning

confidence: 99%

Scalar clouds in charged stringy black hole-mirror system

Zhao

et al. 2015

Eur. Phys. J. C

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It was reported that massive scalar fields can form bound states around Kerr black holes (Herdeiro and Radu, Phys. Rev. Lett. 112:221101, 2014). These bound states are called scalar clouds; they have a real frequency ω = m H , where m is the azimuthal index and H is the horizon angular velocity of Kerr black hole. In this paper, we study scalar clouds in a spherically symmetric background, i.e. charged stringy black holes, with the mirror-like boundary condition. These bound states satisfy the superradiant critical frequency condition ω = q H for a charged scalar field, where q is the charge of the scalar field, and H is the horizon's electrostatic potential. We show that, for the specific set of black hole and scalar field parameters, the clouds are only possible for specific mirror locations r m . It is shown that analytical results of the mirror location r m for the clouds perfectly coincide with numerical results in the q Q 1 regime. We also show that the scalar clouds are also possible when the mirror locations are close to the horizon. Finally, we provide an analytical calculation of the specific mirror locations r m for the scalar clouds in the q Q 1 regime.

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Section: Numerical Procedures and Resultsmentioning

confidence: 99%

Scalar clouds in charged stringy black hole-mirror system

Zhao

et al. 2015

Eur. Phys. J. C

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“…This means that the RN black holes are stable under the perturbations of massive charged scalar fields. Soon after, Degollado et al [41,42] found that the same system can be made unstable by adding a mirror-like boundary condition like the case of the Kerr black hole. However, whether all of the charged black holes have similar properties to the RN black hole is still an interesting question that deserves further studies.…”

Section: Introductionmentioning

confidence: 99%

Superradiant instability of charged scalar field in stringy black hole mirror system

Zhao

2014

Eur. Phys. J. C

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It has been shown that the mass of a charged scalar field in the background of a charged stringy black hole is never able to generate a potential well outside the event horizon to trap the superradiant modes. This is to say that the charged stringy black hole is stable against massive charged scalar perturbations. In this paper we will study the superradiant instability of the massless scalar field in the background of charged stringy black hole due to a mirror-like boundary condition. The analytical expression of the frequencies of unstable superradiant modes is derived by using the asymptotic matching method. It is also pointed out that the black hole mirror system becomes extremely unstable for a large charge q of the scalar field and a small mirror radius r m .

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“…We will show that the variation of the clouds' properties with the mirror location and "quantum numbers" labeling the cloud is qualitatively similar for both acoustic and scalar clouds. Let us remark that superradiance of scalar fields around BHs in a cavity has been studied in the past, for both Kerr [20,27,28] and Reissner-Nordström geometries [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Acoustic clouds: Standing sound waves around a black hole analogue

et al. 2015

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Under certain conditions sound waves in fluids experience an acoustic horizon with analogue properties to those of a black hole event horizon. In particular, a draining bathtub-like model can give rise to a rotating acoustic horizon and hence a rotating black hole (acoustic) analogue. We show that sound waves, when enclosed in a cylindrical cavity, can form stationary waves around such rotating acoustic holes. These acoustic perturbations display similar properties to the scalar clouds that have been studied around Kerr and Kerr-Newman black holes; thus they are dubbed acoustic clouds. We make the comparison between scalar clouds around Kerr black holes and acoustic clouds around the draining bathtub explicit by studying also the properties of scalar clouds around Kerr black holes enclosed in a cavity. Acoustic clouds suggest the possibility of testing, experimentally, the existence and properties of black hole clouds, using analog models.

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Rapid growth of superradiant instabilities for charged black holes in a cavity

Cited by 117 publications

References 33 publications

Scalar clouds in charged stringy black hole-mirror system

Scalar clouds in charged stringy black hole-mirror system

Superradiant instability of charged scalar field in stringy black hole mirror system

Acoustic clouds: Standing sound waves around a black hole analogue

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