Corrected thermodynamics and radiation predictions of modified black bounce compact objects

Abstract

We study the thermodynamic properties and radiation characteristics of a regular compact object obtained by applying the Simpson-Visser (SV) regularisation to the Schwarzschild modified gravity black hole. The resulting SV-MOG spacetime, whose lapse function involves both the MOG coupling parameter alpha and the black-bounce parameter l, smoothly interpolates between a regular black hole, a one-way wormhole, and a traversable wormhole depending on the parameter l. We derive the Hawking temperature and heat capacity for the black hole branch, identifying second-order phase transitions signaled by sign changes in CV, and, for the horizonless wormhole branch where no causal horizon and hence no genuine Hawking radiation exists we instead construct a physically well-defined effective temperature from the Lyapunov exponent of the unstable photon sphere. Quantum gravitational corrections to the entropy are incorporated via logarithmic terms parameterized by coefficients beta1, beta2, whose theoretically preferred ranges in loop quantum gravity and string theory we discuss, and we show that deviations from the Bekenstein-Hawking area law become significant at small horizon radii. A linear scalar-perturbation analysis further shows that the effective radial potential remains non-negative throughout the black-hole exterior and across the wormhole throat, indicating stability against monopole perturbations independently of the thermodynamic stability inferred from the heat capacity.