Quasinormal modes in two-photon autocorrelation and the geometric-optics approximation

Qian, Wei-Liang; Lin, Kai; Kuang, Xiao-Mei; Wang, Bin; Yue, Rui-Hong

doi:10.1140/epjc/s10052-022-10155-w

Cited by 10 publications

(6 citation statements)

References 33 publications

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“…Intriguingly, unstable null geodesics have been revealed to be closely related to a class of quasinormal modes of perturbations in the black hole spacetime [9,10,16,[48][49][50][51][52]. In [9], null geodesics were first found to be connected with quasinormal modes in Schwarzschild and slowly rotating Kerr black holes.…”

Section: Jhep06(2022)060mentioning

confidence: 99%

Quasinormal modes of black holes with multiple photon spheres

Guo

Wang

Yang

et al. 2022

J. High Energ. Phys.

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For a static and spherically symmetric black hole, a photon sphere is composed of circular null geodesics of fixed radius, and plays an important role in observing the black hole. Recently, in an Einstein-Maxwell-scalar model with a non-minimal coupling between the scalar and electromagnetic fields, a class of hairy black holes has been found to possess two unstable and one stable circular null geodesics on the equatorial plane, corresponding to three photon spheres outside the event horizon. In this paper, we study quasinormal modes of the scalar field, which are associated with these circular null geodesics, in the hairy black hole spacetime. In the eikonal regime with l ≫ 1, the real part of the quasinormal modes is determined by the angular velocity of the corresponding circular geodesics. The imaginary part of the quasinormal modes associated with the unstable circular null geodesics encodes the information about the Lyapunov exponent of the corresponding circular geodesics. Interestingly, we find long-lived and sub-long-lived modes, which are associated with the stable and one of the unstable circular null geodesics, respectively. Due to tunneling through potential barriers, the damping times of the long-lived and sub-long-lived modes can be exponentially and logarithmically large in terms of l, respectively.

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Section: Jhep06(2022)060mentioning

confidence: 99%

Quasinormal modes of black holes with multiple photon spheres

Guo

Wang

Yang

et al. 2022

J. High Energ. Phys.

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show abstract

“…As a null vector in the effective metric, the propagation vector of the discontinuity can be viewed as that of a photon. The latter is feasible because the classical notion of a photon's geodesic can be established by approximating the perturbation equation of the electromagnetic field at the geometric-optics limit [37][38][39]. More specifically, at the lowest order, the propagation vector of the waveform manifestly follows the trajectory of a null geodesic.…”

Section: Introductionmentioning

confidence: 99%

Black hole shadow in f(R) gravity with nonlinear electrodynamics*

liu¹,

Qian²,

Chen³

et al. 2023

Chinese Phys. C

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By analyzing the propagation of discontinuity in the nonlinear electrodynamics, we investigate numerically the related black hole shadows of the recently derived rotating black hole solutions in f(R) gravity. In such a context, the geodesic motion of the relevant perturbations is governed by an effective geometry, which is closely related to the underlying spacetime metric. We derive the effective geometry, and the latter is used to determine the trajectory of the propagation vector of an arbitrary finite discontinuity in the electrodynamic perturbations, namely, the photon. Subsequently, the image of the black hole is evaluated using the ray-tracing technique. Moreover, we discuss the physical relevance of metric parameters, such as the nonlinear coupling, spin, and charge, by studying their impact on the resultant black hole shadows.

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“…The measurements are performed in terms of the electromagnetic signals, largely dictated by the strong gravitational lensing. The classical geometric-optics limit [2][3][4] of the electromagnetic waves, referred to as photons, follow the null geodesics of the black hole metric in question. The latter can be derived by analyzing the wavefront propagation at the high frequency limit by treating the amplitude variation as an insignificant quantity.…”

Section: Introductionmentioning

confidence: 99%

Effect of nonlinear electrodynamics on shadows of slowly rotating black holes*

Tang¹,

liu²,

Qian³

et al. 2023

Chinese Phys. C

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In this work, we investigate the effect of nonlinear electrodynamics on the shadows of charged, slowly rotating black holes with the presence of a cosmological constant. Rather than the null geodesic of the background black hole spacetime, the trajectory of a photon, as perturbations of the nonlinear electrodynamic field, is governed by an effective metric. The latter can be derived by analyzing the propagation of a discontinuity of the electromagnetic waveform. Subsequently, the image of the black hole and its shadow can be evaluated using the backward ray-tracing technique. We explore the properties of the resultant black hole shadows of two different scenarios of nonlinear electrodynamics, namely, the logarithmic and exponential forms. In particular, the effects of nonlinear electrodynamics on the optical image are investigated, besides the dependence on other metric parameters, such as the black hole spin and charge. The resulting black hole image and shadow display rich features that potentially lead to observational implications.

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Quasinormal modes in two-photon autocorrelation and the geometric-optics approximation

Cited by 10 publications

References 33 publications

Quasinormal modes of black holes with multiple photon spheres

Quasinormal modes of black holes with multiple photon spheres

Black hole shadow in f(R) gravity with nonlinear electrodynamics*

Effect of nonlinear electrodynamics on shadows of slowly rotating black holes*

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