arXiv subjects

Mozib Bin Awal

Publications and source records attributed to Mozib Bin Awal.

11 recordsLinked to original sources

arXiv2026

Nonperturbative Isentropic Processes in AdS Black Holes with Nonlinear Electrodynamics

We study the isentropic processes in a class of Anti de Sitter black holes coupled to non-linear electrodynamics. We demonstrate that such processes are classically forbidden but can proceed via quantum mechanical tunnelling. We compute the Euclidean action associated with the tunnelling process and analyze its dependence on the black hole charge, horizon radius, and the non-linear electrodynamics parameters characterizing each model. We find that the tunnelling probability is increasingly suppressed as the strength of the non-linearity is enhanced. We further find that smaller black holes exhibit a significantly higher tunnelling probability compared to larger ones, indicating a departure from classical behaviour. We conjecture that this behaviour may be universal across a broad class of black hole spacetimes. We discuss the implications of our results for entropy bounds and their potential relevance to the black hole information loss paradox.

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arXiv2026

Complex Phase Structure and Widom line for Euler Heisenberg black holes

We investigate the supercritical thermodynamics of Euler-Heisenberg AdS black holes within the framework of Lee-Yang phase transition theory. We show that the system admits two distinct critical points associated with a four-phase thermodynamic structure and identify a degenerate higher-order critical point where the two criticalities merge. Extending the thermodynamic description into the complex domain, we determine the distribution of Lee-Yang singularities and construct the corresponding complex phase diagrams. At the degenerate critical point, we find that a well-defined Widom line emerges despite the absence of a conventional coexistence curve, acting as an effective stability boundary in the supercritical regime. In the two-critical-point regime, the complex phase diagram exhibits two distinct Widom lines, one associated with a coexistence curve and the other arising solely from the complex singularity structure. We further show that the Lee-Yang formalism consistently reproduces the expected phase structure for systems with a single critical point and in the absence of criticality. Our results reveal a rich supercritical phase structure and provide new insights into the origin and physical interpretation of Widom lines.

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arXiv2026

Degenerate Bifurcations and Universal Relaxation Scaling in Black Hole Thermodynamics

We present a dynamical systems approach to black hole thermodynamic criticality based on bifurcation equations. We construct an effective thermodynamic landscape in which black holes relax toward equilibrium fixed points. To describe this process, we introduce a flow parameter $τ$, interpreted as a phenomenological relaxation time, which governs the approach toward equilibrium configurations in thermodynamic state space. Near critical points, the thermodynamic flow simplifies into universal mathematical forms, which allows different black holes to be grouped into different universality classes based on their critical behaviour. Our analysis further shows critical slowing down, with relaxation timescales determined entirely by the local bifurcation structure.

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arXiv2026

Critical slowing down of black hole phase transition and universal dynamic scaling in AdS black holes

We investigate the dynamical critical behaviour of black hole phase transitions in anti de Sitter spacetime by extending the stochastic framework of free energy landscape dynamics to Kerr AdS black holes. By analyzing the Langevin evolution of the entropy (in contrast to the horizon radius in the RN-AdS case) near criticality, we demonstrate that the system exhibits pronounced critical slowing down, characterized by a significant increase of the autocorrelation time as the critical point is approached. This behaviour is further confirmed by the lowest eigenvalue of the Fokker-Planck equation. By analysing the dynamics along different thermodynamic paths, including variations in temperature, pressure, and angular momentum, and considering both directions - towards and away from criticality, we find that the relaxation time obeys a robust scaling relation, $τ=|ε|^{-2/3}$ near criticality. The same scaling exponent is obtained for RN-AdS, Kerr-AdS, and Bardeen black holes, suggesting the existence of an underlying universal dynamical behaviour across distinct black hole systems. Our results establish a connection between the geometry of the free energy landscape, stochastic nonequilibrium dynamics, and universal critical phenomena in black hole thermodynamics.

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arXiv2026

Phase Transitions and Chaos Bound in Horava Lifshitz Black Holes using Lyapunov Exponents

We probe the thermodynamic phase structure of four dimensional Horava Lifshitz black holes by Lyapunov exponent analysis. For both massless and massive test particles, the Lyapunov exponent exhibits a multivalued dependence on temperature in regimes with a first-order phase transition, with distinct branches corresponding to small, intermediate, and large black hole phases, and this behaviour disappears at the critical point. The discontinuity in the Lyapunov exponent acts as an effective order parameter with critical exponent $δ=1/2$, consistent with mean-field universality. We also find that the chaos bound is generically violated below a threshold horizon radius, with the violation occurring within the thermodynamically stable phase and persisting even in the absence of a phase transition. These results establish the robustness and universality of Lyapunov exponents as probes of black hole thermodynamics in alternative theories of gravity.

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arXiv2026

Quasi-Periodic Oscillations and Parameter Constraints in ModMax Black Holes

We analyze the impact of ModMax parameter on the dynamics of test particles around black holes and its effect on the characteristics of Quasi-Periodic Oscillations (QPOs). The effect of the ModMax parameter $η$ is studied using the effective potential, angular momentum and the energy of the circular orbits of the test particles. Our analysis shows that increasing $η$ brings about a continuous transition from the RN regime toward the Schwarzschild limit, accompanied by noticeable modifications in the Innermost Stable Circular Orbit (ISCO) and the corresponding Keplerian frequencies. We also explore the dependence of QPO radii on the ModMax parameter $η$ within the framework of the PR, RP, WD, and ER models. Finally, to place observational constraints, we perform a Markov Chain Monte Carlo (MCMC) analysis using QPO data from a range of black hole sources spanning stellar-mass, intermediate-mass, and supermassive scales.

gr-qc↗

arXiv2026

Entanglement Islands, Page curves and Phase Transitions of Kerr-AdS Black Holes

We study the Page curve and information paradox for Kerr AdS black hole in light of entanglement entropy by employing the recently proposed island paradigm. By incorporating the island rule, we show that the entanglement entropy of Kerr AdS black hole grows linearly at early times and declines to a constant value at late times in agreement with the well established Page curve. The novelty of this study resides in the investigation of influence of phase transitions on the page curve in two different ensembles. We find that a first order phase transition results in a sharp discontinuity in the Page curve. We study the evaporation process in different scenarios and find that in all the situations, the Page curve doesn't violate the unitary principle of quantum mechanics.

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arXiv2025

Lyapunov Exponents, Phase Transitions, and Chaos Bound of ModMax AdS Black Holes

We study the thermodynamic phase transition of ModMax anti-de Sitter (AdS) black holes using Lyapunov exponents of massless and massive particles in unstable circular orbits. Our results demonstrate that the thermal profile of the Lyapunov exponent serves as an efficient probe of the black hole's phase structure. We calculate the discontinuity in the Lyapunov exponent across the transition and show that it acts as an order parameter, exhibiting a critical exponent $δ=1/2$ in the vicinity of the critical point. Furthermore, we explore the violation of the chaos bound, finding that the bound is violated when the horizon radius falls below a threshold value. We also examine how the ModMax parameter and the particle's angular momentum modify this threshold, revealing their role in controlling the onset of chaos bound violation.

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arXiv2025

The Interconnection of Cosmological Constant and Renyi Entropy in Kalb-Ramond Black Holes : Insights from Thermodynamic Topology

This paper seeks to establish a connection between the cosmological constant and Renyi entropy within the framework of Kalb-Raymond(K-R) gravity. Our analysis is supported by evidence showing the equivalence of the thermodynamic topology of K-R AdS black holes in the Gibbs-Boltzmann (GB) statistical framework and K-R flat black holes in the Renyi statistical framework. We begin by exploring the thermodynamic topology of K-R black holes in flat spacetimes, focusing on the topological characteristics and phase transition behavior in both statistical frameworks. We find that K-R flat black holes in Renyi statistics exhibit equivalent global and local topological properties to K-R AdS black holes in GB statistics. This equivalence points to a potential connection between the cosmological constant and the Renyi parameter. We derive an approximate relationship between the Renyi parameter and the cosmological constant, which is consistent with similar findings in the literature from a cosmological perspective.

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arXiv2025

Probing Thermodynamic Phase Transitions of 4D R-Charged Black Holes via Lyapunov Exponent

We investigate the thermodynamic phase structure of four-dimensional \textit{R}-charged black holes--characterized by four independent $U(1)$ charges--through the lens of Lyapunov exponents associated with unstable circular orbits of both massless and massive particles. Considering three distinct charge configurations (equal, partially unequal, and fully unequal), we show that the thermal profile of the Lyapunov exponent can effectively probe the black hole phase transitions. Furthermore, we demonstrate that the discontinuous jump in the Lyapunov exponent acts as an order parameter, with the associated critical exponent $δ= 1/2$ near the critical point--consistent across all charge configurations studied. This supports the proposed universality of the exponent and the broader connection between dynamical chaos and thermodynamic phase transitions.

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arXiv2024

Restricted Phase Space Thermodynamics of NED-AdS Black Holes

We study the Restricted Phase Space Thermodynamics (RPST) of magnetically charged Anti de Sitter (AdS) black holes sourced by nonlinear electrodynamics(NED). The first law and the corresponding Euler relation are examined using the scaling properties. While the mass is homogeneous in the first order, the intensive variables are observed to follow zeroth order homogeneity. We use numerical and graphical techniques to find the critical points of the various thermodynamic quantities. By utilizing the re-scaling properties of the equation of states, we study the thermodynamic processes using different pairs of variables. From our analysis, we infer that although the RPS thermodynamics of NED-AdS black hole resembles those of RN-AdS, Kerr-AdS, Kerr-Sen-Ads black holes in most of its aspects, hinting at a possible universality, there exists one particular $μ-C$ process that differs in its behaviour from its counterparts in earlier reported works.

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