Long-lived quasinormal modes, shadows and particle motion in four-dimensional quasi-topological gravity.
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| Title: | Long-lived quasinormal modes, shadows and particle motion in four-dimensional quasi-topological gravity. |
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| Authors: | Lütfüoğlu, Bekir Can1 (AUTHOR) bekir.lutfuoglu@uhk.cz |
| Source: | European Physical Journal C -- Particles & Fields. May2026, Vol. 86 Issue 5, p1-15. 15p. |
| Subjects: | Black holes, Particle motion, Perturbation theory, Gravitation, Geodesics |
| Abstract: | We investigate massive scalar perturbations and several characteristics of particle motion in the spacetime of regular black holes arising in four-dimensional quasi-topological gravity. Quasinormal modes are computed using high-order WKB approximations with Padé resummation and verified through time-domain integration. For moderate values of the scalar-field mass, the time-domain profiles confirm the WKB results with excellent accuracy. As the mass increases, the damping rate decreases substantially, indicating the approach to the quasi-resonant regime of long-lived modes. For sufficiently large masses, the late-time signal becomes dominated by oscillatory power-law tails, which mask the quasi-resonant mode in the time-domain profile. In addition, we analyze photon motion and circular geodesics, including the photon-sphere radius, shadow size, Lyapunov exponent, and ISCO characteristics. These quantities exhibit only moderate deviations from their Schwarzschild values, unlike the Hawking temperature of the black hole. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | We investigate massive scalar perturbations and several characteristics of particle motion in the spacetime of regular black holes arising in four-dimensional quasi-topological gravity. Quasinormal modes are computed using high-order WKB approximations with Padé resummation and verified through time-domain integration. For moderate values of the scalar-field mass, the time-domain profiles confirm the WKB results with excellent accuracy. As the mass increases, the damping rate decreases substantially, indicating the approach to the quasi-resonant regime of long-lived modes. For sufficiently large masses, the late-time signal becomes dominated by oscillatory power-law tails, which mask the quasi-resonant mode in the time-domain profile. In addition, we analyze photon motion and circular geodesics, including the photon-sphere radius, shadow size, Lyapunov exponent, and ISCO characteristics. These quantities exhibit only moderate deviations from their Schwarzschild values, unlike the Hawking temperature of the black hole. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 14346044 |
| DOI: | 10.1140/epjc/s10052-026-15807-9 |
