Integrability of Kerr-Newman spacetime with cloud strings, quintessence and electromagnetic field

Cao, Wenfu; Liu, Wenfang; Wu, Xiaoxia

doi:10.1103/physrevd.105.124039

Cited by 13 publications

(13 citation statements)

References 51 publications

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“…Some works on the circular orbits of particles can be seen in Refs. [36,[63][64][65][66][67], e.g., the issues on the spherical photon orbits around a Kerr BH [63], the dynamics of charged particles moving around Kerr BH with inductive charge and external magnetic field [65], the equivalence between two charged black holes in dynamics of orbits outside the event horizons [36], and the precessing and periodic orbits around hairy black holes in Horndeskis theory [67], were discussed. These studies can be utilized to distinguish different BHs, investigate the properties of spacetime in strong gravitational fields, and subsequently test theories of gravitational interaction.…”

Section: Stability Analysis Of Particles' Circular Orbits Around a Bl...mentioning

confidence: 99%

Properties of Spherically Symmetric Black Holes in the Generalized Brans–Dicke Modified Gravitational Theory

Yang

et al. 2023

Entropy

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The many problems faced by the theory of general relativity (GR) have always motivated us to explore the modified theory of GR. Considering the importance of studying the black hole (BH) entropy and its correction in gravity physics, we study the correction of thermodynamic entropy for a kind of spherically symmetric black hole under the generalized Brans–Dicke (GBD) theory of modified gravity. We derive and calculate the entropy and heat capacity. It is found that when the value of event horizon radius r+ is small, the effect of the entropy-correction term on the entropy is very obvious, while for larger values r+, the contribution of the correction term on entropy can be almost ignored. In addition, we can observe that as the radius of the event horizon increases, the heat capacity of BH in GBD theory will change from a negative value to a positive value, indicating that there is a phase transition in black holes. Given that studying the structure of geodesic lines is important for exploring the physical characteristics of a strong gravitational field, we also investigate the stability of particles’ circular orbits in static spherically symmetric BHs within the framework of GBD theory. Concretely, we analyze the dependence of the innermost stable circular orbit on model parameters. In addition, the geodesic deviation equation is also applied to investigate the stable circular orbit of particles in GBD theory. The conditions for the stability of the BH solution and the limited range of radial coordinates required to achieve stable circular orbit motion are given. Finally, we show the locations of stable circular orbits, and obtain the angular velocity, specific energy, and angular momentum of the particles which move in circular orbits.

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Section: Stability Analysis Of Particles' Circular Orbits Around a Bl...mentioning

confidence: 99%

Properties of Spherically Symmetric Black Holes in the Generalized Brans–Dicke Modified Gravitational Theory

Yang

et al. 2023

Entropy

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“…The seven pieces have analytical solutions as explicit functions of proper time τ. According to the result of Cao et al (2022), the sum of the seven split pieces, i.e., the Hamiltonian H of Equation (31), is integrable. Notice that each of the seven split pieces is integrable or not, irrespective of whether the sum of the seven split pieces is integrable.…”

Section: Reissner-nordström Spacetime With Extra Sourcesmentioning

confidence: 99%

Explicit Symplectic Methods in Black Hole Spacetimes

Wang

Sun

et al. 2022

ApJ

Self Cite

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Many Hamiltonian problems in the solar system are separable into two analytically solvable parts, and thus serve as a great chance to develop and apply explicit symplectic integrators based on operator splitting and composing. However, such constructions are not in general available for curved spacetimes in general relativity and modified theories of gravity because these curved spacetimes correspond to nonseparable Hamiltonians without the two-part splits. Recently, several black hole spacetimes such as the Schwarzschild black hole were found to allow for the construction of explicit symplectic integrators, since their corresponding Hamiltonians are separable into more than two explicitly integrable pieces. Although some other curved spacetimes including the Kerr black hole do not have such multipart splits, their corresponding appropriate time-transformation Hamiltonians do. In fact, the key problem in obtaining symplectic analytically integrable decomposition algorithms is how to split these Hamiltonians or time-transformation Hamiltonians. Considering this idea, we develop explicit symplectic schemes in curved spacetimes. We introduce a class of spacetimes whose Hamiltonians are directly split into several explicitly integrable terms. For example, the Hamiltonian of a rotating black ring has a 13-part split. We also present two sets of spacetimes whose appropriate time-transformation Hamiltonians have the desirable splits. For instance, an eight-part split exists in a time-transformed Hamiltonian of a Kerr–Newman solution with a disformal parameter. In this way, the proposed symplectic splitting methods can be used widely for long-term integrations of orbits in most curved spacetimes we know of.

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“…However, not all external electromagnetic fields must admit the onset of chaotic motion. Recently, the authors of [121] proved the integrability of charged particles by moving around the Kerr-Newman black hole surrounded by cloud strings, quintessence, and an electromagnetic field. If the cosmological constant Λ included in the model is nonvanishing, then the fourth constant is absent and chaos may occur.…”

Section: Orbital Dynamics Influenced By the Electromagnetic Parametermentioning

confidence: 99%

Chaos in a Magnetized Brane-World Spacetime Using Explicit Symplectic Integrators

Huang

2022

Universe

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A brane-world metric with an external magnetic field is a modified theory of gravity. It is suitable for the description of compact sources on the brane such as stars and black holes. We design a class of explicit symplectic integrators for this spacetime and use one of the integrators to investigate how variations of the parameters affect the motion of test particles. When the magnetic field does not vanish, the integrability of the system is destroyed. Thus, the onset of chaos can be allowed under some circumstances. Chaos easily occurs when the electromagnetic parameter becomes large enough. Dark matter acts as a gravitational force, so that chaotic motion can become more obvious as dark matter increases. The gravity of the black hole is weakened with an increasing positive cosmological parameter; therefore, the extent of chaos can be also strengthened. The proposed symplectic integrator is applied to a ray-tracing method and the study of such chaotic dynamics will be a possible reference for future studies of brane-world black hole shadows with chaotic patterns of self-similar fractal structures based on the Event Horizon Telescope data for M87* and Sagittarius A*.

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Integrability of Kerr-Newman spacetime with cloud strings, quintessence and electromagnetic field

Cited by 13 publications

References 51 publications

Properties of Spherically Symmetric Black Holes in the Generalized Brans–Dicke Modified Gravitational Theory

Properties of Spherically Symmetric Black Holes in the Generalized Brans–Dicke Modified Gravitational Theory

Explicit Symplectic Methods in Black Hole Spacetimes

Chaos in a Magnetized Brane-World Spacetime Using Explicit Symplectic Integrators

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