This paper addresses a potential validation of the weak gravity conjecture (WGC) with the weak cosmic censorship conjecture (WCCC), as a significant challenge in quantum gravity. We explore the viability of the WGC and WCCC in the context of the Kerr-Newman-Kiselev-Letelier (KNKL) black hole. Although these conjectures appear unrelated, but surprising connection between these conjectures establishes a bridge between the quantum and the cosmic. By imposing specific constraints on the black hole's parameters, we demonstrate that the WGC and WCCC can be compatible in certain regions. We examine the properties of the KNKL black hole for <math altimg='si1.svg'><mi>q</mi><mo stretchy='false'>/</mo><mi>m</mi><mo linebreak='goodbreak' linebreakstyle='after'>&gt;</mo><msub><mrow><mo stretchy='false'>(</mo><mi>Q</mi><mo stretchy='false'>/</mo><mi>M</mi><mo stretchy='false'>)</mo></mrow><mrow><mi>e</mi><mi>x</mi><mi>t</mi></mrow></msub></math>, where <math altimg='si2.svg'><msub><mrow><mo stretchy='false'>(</mo><mi>Q</mi><mo stretchy='false'>/</mo><mi>M</mi><mo stretchy='false'>)</mo></mrow><mrow><mi>e</mi><mi>x</mi><mi>t</mi></mrow></msub></math> is the charge-to-mass ratio of a large extremal black hole. We present figures to test the validity of both conjectures simultaneously. Without the spin parameter <italic>a</italic>, the cloud of string parameter <italic>b</italic>, quintessence parameter <italic>&#947;</italic>, and equation of state parameter <italic>&#969;</italic>, the black hole either has two event horizons if <math altimg='si3.svg'><msup><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msup><mo stretchy='false'>/</mo><msup><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>&#8804;</mo><mn>1</mn></math> or none event horizon if <math altimg='si4.svg'><msup><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msup><mo stretchy='false'>/</mo><msup><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msup><mo linebreak='goodbreak' linebreakstyle='after'>&gt;</mo><mn>1</mn></math> which leads to a naked singularity that contradicts the WCCC. However, when <italic>a</italic>, <italic>b</italic>, <italic>&#947;</italic>, and <italic>&#969;</italic> are present, the black hole has event horizons in some regions in the <math altimg='si4.svg'><msup><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msup><mo stretchy='false'>/</mo><msup><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msup><mo linebreak='goodbreak' linebreakstyle='after'>&gt;</mo><mn>1</mn></math> that ensure the singularity is covered and both the WGC and WCCC are fulfilled. Actually, we face this issue in the extremality state of the black hole viz these conjectures remain viable, with the black hole maintaining an event horizon. We conclude that certain regions of <italic>a</italic>, <italic>b</italic>, <italic>&#947;</italic>, and <italic>&#969;</italic> parameters can make the WGC and WCCC compatible, indicating their agreement when these parameters are present.

Iran

Saeed Noori Gashti

Azerbaijan

Behnam Pourhassan

Cosmic-quantum connections: Assessing the viability of weak gravity and weak cosmic censorship conjectures in Kerr-Newman-Kiselev-Letelier black hole

In this work we study the warm inflation mechanism in the presence of the Barrow holographic dark energy model. Warm inflation differs from other forms of inflation primarily in that it assumes that radiation and inflaton fields exist and interact throughout the inflationary process. After the warming process, energy moves from the inflaton to the radiation as a result of the interaction, keeping the cosmos warm. Here we have set up the warm inflationary mechanism using Barrow holographic dark energy as the driving agent. Warm inflation has been explored in a highly dissipative regime and interesting results have been obtained. It is seen that the Barrow holographic dark energy can successfully drive a warm inflationary scenario in the early universe. Finally, the model was compared with the observational data, and compliance was found.

India

Moli Ghosh

Prabir Rudra

Surajit Chattopadhyay

Canada

Warm inflation with Barrow holographic dark energy

In this paper, we delve into the thermodynamic topology of AdS Einstein–Gauss–Bonnet black holes, employing non-extensive entropy formulations such as Barrow, Rényi, and Sharma–Mittal entropy within two distinct frameworks: bulk boundary and restricted phase space (RPS) thermodynamics. Our findings reveal that in the bulk boundary framework, the topological charges, influenced by the free parameters and the Barrow non-extensive parameter $$(\delta )$$ , exhibit significant variability. Specifically, we identify three topological charges $$(\omega = +1, -1, +1)$$ . When the parameter $$\delta $$ increases to 0.9, the classification changes, resulting in two topological charges $$(\omega = +1, -1)$$ . When $$\delta $$ is set to zero, the equations reduce to the Bekenstein–Hawking entropy structure, yielding consistent results with three topological charges. Additionally, setting the non-extensive parameter $$\lambda $$ in Rényi entropy to zero increases the number of topological charges, but the total topological charge remains (W = +1). The presence of the Rényi non-extensive parameter alters the topological behavior compared to the Bekenstein–Hawking entropy. Sharma–Mittal entropy shows different classifications and the various numbers of topological charges influenced by the non-extensive parameters $$\alpha $$ and $$\beta $$ . When $$\alpha $$ and $$\beta $$ have values close to each other, three topological charges with a total topological charge $$(W = +1)$$ are observed. Varying one parameter while keeping the other constant significantly changes the topological classification and number of topological charges. In contrast, the RPS framework demonstrates remarkable consistency in topological behavior. Under all conditions and for all free parameters, the topological charge remains $$(\omega = +1)$$ with the total topological charge $$(W = +1)$$ . This uniformity persists even when reduced to Bekenstein–Hawking entropy, suggesting that the RPS framework provides a stable environment for studying black hole thermodynamics across different entropy models. These findings underscore the importance of considering various entropy formulations and frameworks to gain a comprehensive understanding of black hole thermodynamics.

Saeed Gashti

Non-extensive entropy and holographic thermodynamics: topological insights

In this paper, we study quantum effects on transport properties of charged anti-de Sitter (AdS) black holes, focusing on non-perturbative corrections to the shear viscosity-to-entropy ratio. We consider exponential corrections to both the entropy and transport coefficients, examining their impact on the Kovtun–Son–Starinets (KSS) bound. Through detailed analysis, we demonstrate that quantum corrections significantly modify transport phenomena, particularly in the small-horizon-radius regime. We explore three scenarios: unmodified shear viscosity with quantum-corrected entropy, quantum corrections to both quantities, and preservation of the universal ratio. Our results show that electrical conductivity, bulk viscosity, and thermal conductivity receive substantial modifications from quantum effects while maintaining consistency with established transport laws. The analysis reveals that for the positive correction coefficient, the KSS bound can be violated, while for the negative correction coefficient, it remains valid. We demonstrate these effects through numerical analysis and graphical representations, providing insight into quantum transport phenomena in strongly coupled systems.

Türkiye

İzzet Sakallı

Transport phenomena and KSS bound in quantum-corrected AdS black holes

In this paper, we study the thermodynamic topology of AdS Einstein–power–Yang–Mills black holes, examining them through both the bulk-boundary and restricted phase space (RPS) frameworks. We consider various non-extensive entropy models, including Barrow ( $$\delta $$ ), Rényi ( $$\lambda $$ ), Sharma–Mittal ( $$\beta $$ , $$\alpha $$ ), Kaniadakis ( ), and Tsallis-Cirto entropy ( $$\Delta $$ ). Initially, we analyze the thermodynamic topology within the bulk-boundary framework. Our findings highlight the influence of free parameters on topological charges. We observe two topological charges $$(\omega = +1, -1)$$ with respect to the non-extensive Barrow parameter and also with ( $$\delta =0$$ ) in Bekenstein–Hawking entropy. For Rényi entropy, different topological charges are observed depending on the value of the $$\lambda $$ with a notable transition from three topological charges $$(\omega = +1, -1, +1)$$ to a single topological charge $$(\omega = +1)$$ as $$\lambda $$ increases. Also, by setting $$\lambda $$ to zero results in two topological charges $$(\omega = +1, -1)$$ . Sharma–Mittal entropy exhibits three distinct ranges of topological charges influenced by the $$\alpha $$ and $$\beta $$ with different classifications viz, if $$\beta $$ exceeds $$\alpha $$ , we will have $$(\omega = +1,-1,+1)$$ ; if $$\beta = \alpha $$ , we have $$(\omega = +1,-1)$$ ; and if $$\alpha $$ exceeds $$\beta $$ , we obtain $$(\omega = -1)$$ . Also, Kaniadakis entropy shows variations in topological charges; viz., we observe $$(\omega = +1,-1)$$ for any acceptable value of K, except when $$K=0$$ , where a single topological charge $$(\omega = -1)$$ appears. In the case of Tsallis-Cirto entropy, for small parameter $$\Delta $$ values, we have $$(\omega = +1)$$ and when $$\Delta $$ increases to 0.9, we will have $$(\omega = +1, -1)$$ . A particularly intriguing aspect of this research is its application to the RPS framework. When we extend our analysis to this space using the specified entropies, we find that the topological charge consistently remains $$(\omega = +1)$$ independent of the specific values of the free parameters for Rényi, Sharma–Mittal, and Tsallis–Cirto. Additionally, for Barrow entropy in RPS, when $$\delta $$ increases from 0 to 0.8, the number of topological charges rises. Finally for Kaniadakis entropy, at small values of , we observe $$(\omega = +1)$$ . However, as the non-extensive parameter increases, we encounter different topological charges and classifications with $$(\omega = +1, -1)$$ .

Thermodynamic topology and phase space analysis of AdS black holes through non-extensive entropy perspectives

We investigate how thermal fluctuations affect the properties of five-dimensional Kerr–Newman black holes, focusing particularly on the shear viscosity to entropy ratio. Our analysis incorporates logarithmic corrections to the Bekenstein–Hawking entropy and examines their impact on black hole thermodynamics. We explore three approaches to studying the shear viscosity-entropy ratio in the presence of thermal fluctuations: considering independent shear viscosity, thermally corrected shear viscosity, and an independent ratio assumption. Notably, we find that the lower bound of $$\eta /S \ge 1/4\pi $$ remains valid even with thermal fluctuations, though the specific behavior depends on the black hole mass and correction parameter. Our results suggest that thermal fluctuations generally decrease the ratio for massive black holes while maintaining the universal lower bound. This work extends our understanding of quantum corrections to black hole transport properties.

Iraq

Aram Brzo

Thermal fluctuation effects on shear viscosity to entropy ratio in five-dimensional Kerr–Newman black holes

In this paper, we investigate the scales at which quantum gravitational corrections can be detected in a black hole using information theory. This is done by calculating the Kullback-Leibler divergence for the probability distributions obtained from the Parikh-Wilczek formalism. We observe that as quantum gravitational corrections increase with decrease in scale, the increase the Kullback-Leibler divergence between the original and quantum gravitational corrected probability distributions will also increase. To understand the impact of such quantum gravitational corrections we use Fisher information. We observe that it again increases as we decrease the scale. We obtain these results for higher-dimensional black holes and observe this behavior for Kullback-Leibler divergence and Fisher information also depending on the dimensions of the black hole. Furthermore, we observe that the Fisher information is bounded and approaches a fixed value. Thus, information about the nature of quantum gravitational corrections itself is intrinsically restricted by quantum gravity. Thus, this work establishes an intrinsic epistemic boundary within quantum gravity.

Xiaoping Shi

Qatar

Salman Wani

 Saif-Al-Khawari

Farideh Kazemian

Naveed Shah

United Kingdom

Belgium

Mir Faizal

Information theoretical approach to detecting quantum gravitational corrections

We consider a modified gravity by higher-derivative gravity coupled with non-local terms and Maxwell electrodynamics. By employing the effective field theory framework for quantum gravity, we compute quantum corrections to the entropy of charged AdS black holes, focusing on second-order curvature terms. By incorporating scale-dependent coefficients, we establish that the Wald entropy is renormalization group (RG) invariant, confirming the robustness of the framework. Additionally, quantum corrections to thermodynamic quantities-temperature, pressure, specific heat, and Helmholtz free energy-are derived, all satisfying the first-law of thermodynamics. Specific heat and Helmholtz free energy also exhibit RG invariance, demonstrating stability under scale transformations. These findings highlight the effectiveness of the approach in describing quantum modifications to charged AdS black hole thermodynamics, offering insights into the interplay between quantum gravity and black hole physics.

Germany

Ruben Campos Delgado

Kazakhstan

Sudhaker Upadhyay

Hoda Farahani

Himanshu Kumar

Quantum gravitational corrections to the geometry of charged AdS black holes

We investigate entanglement islands and the Page curve in the framework of Horndeski gravity on a Karch-Randall braneworld background. In particular, treating the holographic boundary conformal field theory analytically we find that the Horndeski parameters significantly alter the behavior of the Page curve compared to standard general relativity, a feature caused by the nontrivial geometry induced by the Horndeski scalar field. Interestingly enough, the geometry far from the AdS limit plays a more significant role compared to previous studies. This suggests that Horndeski gravity introduces important modifications to the distribution of quantum information in the holographic model. Finally, we claim that holographic consistency can be used reversely to impose constraints on Horndeski gravity itself, providing a new tool for probing the validity of modified gravity theories.

Brazil

Fabiano Santos

Chile

China

Greece

Emmanuel Saridakis

Ukraine

Oleksii Sokoliuk

Alexander Baransky

Emre Kahya

Holographic boundary conformal field theory within Horndeski gravity

In this paper, we study the thermodynamic properties and stability of static charged BTZ black holes with the inclusion of higher-order quantum corrections. The corrections to the entropy, mass, and Helmholtz free energy are derived, revealing the intricate interplay between quantum effects and classical gravitational forces in the context of black hole thermodynamics. The study of the specific heat capacity shows that higher-order corrections stabilize the system by removing the instabilities present at lower orders. The analysis of the van der Waals-like isotherms demonstrates the continuous transition from a highly compressible to an almost incompressible regime as the volume is decreased, akin to the behavior of supercritical fluids. Notably, the isotherms do not exhibit any regions of negative compressibility, indicating the absence of instabilities. Furthermore, the convexity of the Helmholtz free energy as a function of volume confirms the stability of the charged BTZ black hole system. These findings provide valuable insights into the complex thermodynamic landscape of three-dimensional black holes and the role of quantum corrections in shaping their behavior.

Stabilizing effects of higher-order quantum corrections on charged BTZ black hole thermodynamics