In this paper, we computed the logarithmic corrections of entropy for the near-extremal Kerr-Newman black holes in $$ \mathcal{N} $$ = 2 supergravity theory applying the Euclidean path integral approach in near-horizon geometry. In the near-horizon extremal Kerr geometry, analogous to the AdS × $\textit{S}$ structure, there exists a set of normalizable zero modes associated with reparameterization of boundary time. The one-loop approximation to the Euclidean near-horizon extremal Kerr partition function exhibits an infrared divergence because of the path integral over these zero modes. Carrying out the leading finite temperature correction in the near-horizon extremal Kerr scaling limit, we control this divergence. Further, treating the near-horizon geometry of the near-extremal black hole as a perturbation around its extremal counterpart, we computed the corresponding corrections using a modified heat kernel approach. This method incorporates both extremal and near-extremal contributions and represents a novel solution within the context of charged rotating black holes in $$ \mathcal{N} $$ = 2 supergravity theories.

India

Ashes Modak

Aditya Singh

Binata Panda

Logarithmic corrections for near-extremal Kerr-Newman Black holes

We investigate the information paradox in the four-dimensional Kerr–Newman black hole by employing the recently proposed island paradigm. To accurately capture the behavior of entanglement entropy in Kerr–Newman spacetime, we analyze the form of quantum fields in the near-horizon limit. We demonstrate the field can be effectively described by a reduced two-dimensional field theory. Under the framework of this reduced two-dimensional theory, the entanglement entropy of radiation satisfies the Page curve. We also examine the impact of angular momentum and charges on the Page time and the scrambling time. A step further, we concentrate on analyzing the near extremal case. Resort to the Kerr/CFT correspondence, the near-horizon geometry of near extremal Kerr–Newman black holes can be taken account for a warped AdS geometry. In this scenario, the low-energy effective degrees of freedom are dominated by the Schwarzian zero mode, resulting in a one-loop correction to the partition function. The entanglement entropy is subsequently recalculated under the thermodynamic with corrections. Through explicit calculations, we finally find that the Page time and the scrambling time exhibits quantum delays. This strongly suggests that the near extremal geometry is governed by the Schwarzian dynamics, in which quantum fluctuations result in a reduced rate of information leakage. Moreover, we provide a rigorous discussion on the validity of the island formula and compute the entanglement entropy in Kerr–Newman AdS spacetime as a supplementary example. Our findings further substantiate information conservation and extend the island paradigm to the most general class of stationary spacetime.

China

Ming-Hui Yu

Xian-Hui Ge

Islands in Kerr–Newman black holes

Near-extremal black holes have a long AdS throat in their near-horizon region. Quantum fluctuations in the throat region are effectively governed by a quantum version of Jackiw-Teitelboim gravity with matter and are strongly coupled at low temperatures. We investigate how these quantum fluctuations affect the spectrum of emission of particles during Hawking radiation. We systematically consider the cases of Kerr and Kerr-Newman black holes for emission of scalar particles and discuss photon and graviton emission from the Kerr background. We find that at very low temperatures the quantum fluctuations radically change the nature of particle emission. Unlike the generic suppression of particle emission in the Reissner-Nordström case, we uncover that for particles with non-vanishing angular momentum, the quantum-corrected emission can be substantially enhanced with respect to the standard semiclassical result.

Sabyasachi Maulik

United States

Xin Meng

Italy

Leopoldo Pando Zayas

Quantum-corrected Hawking radiation from near-extremal Kerr-Newman black holes

We investigate the influence of a scalar field on particle dynamics and electromagnetic phenomena in the spacetime of a gravitational compact object described by the Fisher-Janis-Newman-Winicour (FJNW) solution. The motion of test particles is analyzed using the Hamilton-Jacobi formalism, with particular attention to the innermost stable circular orbit (ISCO). We further explore photon motion and black hole shadows, deriving analytic expressions for the photon sphere radius and critical impact parameter. Applying these results to Event Horizon Telescope (EHT) observations of M87 and Sgr A, we show that the predicted shadow sizes remain consistent with the measured values within the 1 <italic>&#963;</italic> confidence interval, thereby constraining the scalar parameter. In addition, we obtain the analytical solution of Maxwell&#8217;s equations for the vector potential produced by a stationary current loop in the FJNW background. The resulting magnetic field exhibits a uniform structure in the interior region, reminiscent of the Wald solution, while in the exterior region it behaves like a dipolar field. We find that the external magnetic field strength decreases with increasing scalar parameter, in contrast to the tidal charge scenario of relativistic stars.

Uzbekistan

Bekzod Rahmatov

Bobur Turimov

Sardor Murodov

Khurshida Khaknazarova

Sulton Usanov

Murodbek Vapayev

Zebo Avezmuratova

Magnetic field by current loop in the Janis-Newman-Winicour spacetime

Thailand

David Senjaya

Erratum to: Revisiting Kerr–Newman black hole’s charged scalar cloud: flux balance

In this paper, we investigate Lyapunov exponents associated with chaotic motions of both massless and massive particles in the vicinity of a Kerr-Newman AdS black hole. Our exploration focuses on their correlations with the black hole phase transition and the chaos bound. The results demonstrate that these exponents serve as effective probes of the phase transition, with the chaotic Lyapunov exponent of the massless particle offering a more precise characterization. Further calculations indicate that critical exponents linked to these Lyapunov exponents are uniformly 1/2. Notably, the violation of the chaos bound occurs irrespective of whether a phase transition is taking place. Through comparative analysis, we identify a critical radius, and the violation consistently arises when the black hole’s radius is less than this critical radius. Moreover, this violation is observed in the spacetime of the stable small black hole during the phase transition.

Chuang Yang

Malaysia

Chuanhong Gao

Deyou Chen

Xiaoxiong Zeng

Lyapunov exponents, phase transition and chaos bound in Kerr-Newman AdS spacetime

In the present study, we investigate the quasibound states and scalar cloud of relativistic charged scalar fields bound to a Kerr–Newman black hole. We present the exact eigensolutions of the governing Klein–Gordon equation with non-minimal coupling in the black hole background. By imposing boundary conditions on the quasibound states, we are able to find the exact complex quasibound state frequencies of the corresponding radial wave functions in terms of the confluent Heun polynomial. The quantization formula obtained here allows us to determine the exact resonance frequency of a charged scalar cloud, thereby revisiting and extending the earlier result derived through the asymptotic matching approach. Our analysis shows that a stationary configuration can exist only when the charge coupling satisfies $$qr_Q<0$$ . In this case, the scalar cloud remains stationary due to a flux balance: an outgoing flux from the Cauchy horizon compensates for the ingoing particle flux at the event horizon. This mechanism distinguishes scalar clouds from ordinary quasibound states, where such a compensating flux is absent.

Revisiting Kerr–Newman black hole’s charged scalar cloud: flux balance

The production of multiple Higgs bosons at the CERN LHC provides a direct way to measure the trilinear and quartic Higgs self-interaction strengths as well as potential access to beyond the standard model effects that can enhance production at large transverse momentum $\textit{p}$ . The largest event fraction arises from the fully hadronic final state in which every Higgs boson decays to a bottom quark-antiquark pair ( $$\text{b}\overline{\text{b} }$$ ). This introduces a combinatorial challenge known as the $\textit{jet assignment problem}$: assigning jets to sets representing Higgs boson candidates. Symmetry-preserving attention networks (SPA-Nets) have been developed to address this challenge. However, the complexity of jet assignment increases when simultaneously considering both $$\text{H}\to \text{b}\overline{\text{b} }$$ reconstruction possibilities, i.e., two “resolved” small-radius jets each containing a shower initiated by a b quark or one “boosted” large-radius jet containing a merged shower initiated by a $$\text{b}\overline{\text{b} }$$ pair. The latter improves the reconstruction efficiency at high $\textit{p}$ . In this work, we introduce a generalization to the SPA-Net approach to simultaneously consider both boosted and resolved reconstruction possibilities and unambiguously interpret an event as “fully resolved”, “fully boosted”, or in between. We report the performance of baseline methods, the original SPA-Net approach, and our generalized version on nonresonant HH and HHH production at the LHC. Considering both boosted and resolved topologies, our SPA-Net approach increases the Higgs boson reconstruction purity by 56–80% and the efficiency by 37–38% compared to the baseline method depending on the final state.

Haoyang Li

Marko Stamenkovic

Alexander Shmakov

Michael Fenton

Darius Chao

Kaitlyn White

Caden Mikkelsen

Serbia

Jovan Mitić

Cristina Suarez

Melissa Quinnan

Greg Landsberg

Harvey Newman

Pierre Baldi

Daniel Whiteson

Javier Duarte

Reconstruction of boosted and resolved multi-Higgs-boson events with symmetry-preserving attention networks

We employ the Poincaré section, fast Lyapunov indicator, recurrence analysis, bifurcation diagram and basins of attraction to investigate the dynamical behaviors of the motion of particles around a new dyonic Kerr–Newman black hole immersed in the Melvin-swirling universe presented in (Di Pinto et al. in J High Energy Phys 06:150, 2025). We note that the swirling parameter $\textit{j}$ and magnetic field strength $\textit{B}$ make the equations of motion for particles nonseparable, and confirm the presence of chaotic behavior in the motion in this dyonic Kerr–Newman–Melvin-swirling spacetime and its sub-cases by removing the conical singularities and removing both the conical singularities and the Dirac strings. We observe that both the number of chaotic orbits and the chaotic region increase with the increase of the parameters $\textit{j}$ and $\textit{B}$, but decrease as the electric charge $\textit{Q}$, magnetic charge $\textit{H}$ or spin parameter $\textit{a}$ increases. Moreover, we find that the presence of $\textit{j}$ changes the ranges of $\textit{B}$, $\textit{Q}$, $\textit{H}$ and $\textit{a}$ where the chaotic motion appears for particles. The swirling parameter together with the magnetic field strength, electric charge, magnetic charge and spin parameter yields richer physics in the motion of particles for the spacetime of a dyonic Kerr–Newman black hole immersed in the Melvin-swirling universe.

Deshui Cao

Lina Zhang

Songbai Chen

Qiyuan Pan

Jiliang Jing

Chaotic motion of particles around a dyonic Kerr–Newman black hole immersed in the Melvin-swirling universe

Based on studies of orbital periods in Kerr black hole spacetimes, Hod conjectured the existence of a universal lower bound on the orbital period for compact objects. In this work, we test this bound for Kerr–Newman black holes using both analytical and numerical methods. By choosing different charge and spin of Kerr–Newman black holes, we establish a lower bound on the orbital period for Kerr–Newman black holes expressed as $$T(r)\geqslant 4\pi M$$ , where $\textit{r}$ is the orbital radius, $\textit{T}$($\textit{r}$) is the orbital period observed from infinity and $\textit{M}$ is the black hole mass. This bound is consistent with Hod’s conjecture. Moreover, we numerically demonstrate that the lower bound is achieved at the extreme Kerr limit in the absence of charge. Our findings support Hod’s conjectured lower bound within the Kerr–Newman family. However, they do not constitute a universal proof for arbitrary black holes.

Yan Peng

The lower bound on the orbital period of Kerr–Newman black holes