by jsendak | Apr 24, 2025 | GR & QC Articles
arXiv:2504.15318v1 Announce Type: new
Abstract: We examine the impact of non-perturbative quantum corrections to the entropy of both charged and charged rotating quasi-topological black holes, with a focus on their thermodynamic properties. The negative-valued correction to the entropy for small black holes is found to be unphysical. Furthermore, we analyze the effect of these non-perturbative corrections on other thermodynamic quantities, including internal energy, Gibbs free energy, charge density, and mass density, for both types of black holes. Our findings indicate that the sign of the correction parameter plays a crucial role at small horizon radii. Additionally, we assess the stability and phase transitions of these black holes in the presence of non-perturbative corrections. Below the critical point, both the corrected and uncorrected specific heat per unit volume are in an unstable regime. This instability leads to a first-order phase transition, wherein the specific heat transitions from negative to positive values as the system reaches a stable state.
Examining Non-Perturbative Quantum Corrections to Black Hole Entropy
We explore the impact of non-perturbative quantum corrections on the entropy of charged and charged rotating quasi-topological black holes. The focus is on understanding the thermodynamic properties of these black holes and the implications of the corrections.
Unphysical Negative-Valued Corrections for Small Black Holes
Our analysis reveals that the non-perturbative correction leads to entropy values that are negative for small black holes. However, these negative values are considered unphysical. This discrepancy raises questions about the validity of the correction for small horizon radii.
Effects on Other Thermodynamic Quantities
In addition to entropy, we investigate the effects of non-perturbative corrections on various thermodynamic quantities such as internal energy, Gibbs free energy, charge density, and mass density. These quantities can provide further insights into the behavior of these black holes.
Significance of Correction Parameter at Small Horizon Radii
Our findings highlight the importance of the sign of the correction parameter for measuring the thermodynamic properties of black holes with small horizon radii. This observation suggests that the correction parameter may play a crucial role in understanding the physics at this scale.
Stability and Phase Transitions
We also assess the stability and phase transitions of these black holes considering the presence of non-perturbative corrections. Our results show that both the corrected and uncorrected specific heat per unit volume are in an unstable regime below the critical point. This instability leads to a first-order phase transition where the specific heat transitions from negative to positive values as the system reaches a stable state.
Roadmap to the Future
While this study provides valuable insights into the effects of non-perturbative quantum corrections on the thermodynamic properties of black holes, there are several challenges and opportunities to be addressed in future research.
Challenges
- Validity of unphysical negative entropy values for small black holes
- Understanding the underlying reasons for the instability of specific heat per unit volume in the unstable regime
- Further investigation into the role of the correction parameter at small horizon radii
Opportunities
- Exploring alternative approaches to account for non-perturbative quantum corrections
- Investigating the implications of these corrections on other black hole properties beyond thermodynamics
- Examining the connection between non-perturbative corrections and quantum gravitational effects
Overall, the study of non-perturbative quantum corrections to black hole thermodynamics opens up new avenues for understanding the fundamental nature of black holes and the interplay between quantum mechanics and gravity. Further research in this area will contribute to a deeper understanding of black hole physics and its theoretical implications.
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by jsendak | Apr 16, 2025 | GR & QC Articles
arXiv:2504.10528v1 Announce Type: new
Abstract: This work explores the thermodynamic characteristics and geothermodynamics of a Bardeen black hole (BH) that interacts with a string cloud and is minimally connected to nonlinear electrodynamics. To avoid the singularities throughout the cosmic evolution, we consider an entropy function which comprises five parameters. In addition, by employing this entropy function for the specific range of parameters, we obtain the representations of BH entropy based on the holographic principle. Moreover, we employ this entropy function to investigate its impact on the thermodynamics of the BH by studying various thermodynamic properties like mass, temperature, heat capacity, and Gibbs free energy for numerous scalar charge and string cloud values. To support our investigation, we use various geothermodynamics formalisms to evaluate the stable behavior and identify different physical scenarios. Furthermore, in this analysis, we observe that only one entropy formalism provides us with better results regarding the thermodynamic behavior of the BH. Moreover, it is shown that one of the entropy models provides a thermodynamic geometric behavior compared to the other entropy models.
This work examines the thermodynamic characteristics and geothermodynamics of a Bardeen black hole (BH) interacting with a string cloud and connected to nonlinear electrodynamics. The study aims to avoid singularities throughout cosmic evolution by considering an entropy function with five parameters. This entropy function is then used to determine BH entropy based on the holographic principle and investigate its impact on various thermodynamic properties such as mass, temperature, heat capacity, and Gibbs free energy for different scalar charge and string cloud values.
To support the investigation, various geothermodynamics formalisms are employed to evaluate the stable behavior and identify different physical scenarios. The analysis reveals that only one entropy formalism yields better results concerning the BH’s thermodynamic behavior. Furthermore, one entropy model is found to provide a more thermodynamic geometric behavior compared to the other entropy models.
Roadmap for readers:
- Introduction: Provide an overview of the study’s objectives and the importance of exploring the thermodynamic characteristics and geothermodynamics of a Bardeen BH interacting with a string cloud.
- Entropy function: Explain the entropy function used in the study, highlighting its five parameters and the motivation behind its selection to avoid singularities.
- Holographic principle: Discuss how the entropy function is employed to determine BH entropy based on the holographic principle, emphasizing the significance of this approach.
- Thermodynamic properties: Present the investigation of various thermodynamic properties, including mass, temperature, heat capacity, and Gibbs free energy, for different scalar charge and string cloud values. Analyze the results and their implications.
- Geothermodynamics formalisms: Describe the utilization of different geothermodynamics formalisms to evaluate the stable behavior and identify physical scenarios. Compare the outcomes obtained from different entropy models.
- Conclusion: Summarize the main findings of the study, highlighting the entropy model that provides better results and a more thermodynamic geometric behavior. Discuss the implications and potential future directions.
Potential challenges:
- Understanding the technical aspects of thermodynamic characteristics and geothermodynamics for a BH interacting with a string cloud and connected to nonlinear electrodynamics.
- Grasping the mathematical representation and significance of the entropy function with five parameters and its role in avoiding singularities.
- Interpreting the results and implications of the investigation on various thermodynamic properties.
- Comprehending the different geothermodynamics formalisms used and their application in evaluating stable behavior and identifying physical scenarios.
Potential opportunities:
- Gaining insights into the thermodynamic behavior and characteristics of a BH interacting with a string cloud, which can contribute to our understanding of black holes and their evolution.
- Exploring the potential applications of the holographic principle in determining BH entropy and its implications.
- Identifying connections between different entropy models and their implications on the geometric behavior of the BH.
- Potential future collaborations and research to further explore the thermodynamics and geothermodynamics of BHs interacting with string clouds and connected to nonlinear electrodynamics.
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by jsendak | Apr 15, 2025 | GR & QC Articles
arXiv:2504.08796v1 Announce Type: new
Abstract: This paper employs Laurent series expansions and the Robson–Villari–Biancalana (RVB) method to provide a refined derivation of the Hawking temperature for two newly introduced topological black hole solutions. Previous calculations have demonstrated inconsistencies when applying traditional methods to such exotic horizons, prompting the need for a more thorough mathematical analysis. By systematically incorporating higher-order terms in the Laurent expansions of the metric functions near the horizon and leveraging the topological features characterized by the Euler characteristic, we reveal additional corrections to the Hawking temperature beyond standard approaches. These findings underscore the subtle interplay between local geometry, spacetime topology, and quantum effects. The results clarify discrepancies found in earlier works, present a more accurate representation of thermodynamic properties for the black holes in question, and suggest broader implications for topological structures in advanced gravitational theories.
Refining the Derivation of Hawking Temperature for Topological Black Holes
In this paper, we employ Laurent series expansions and the Robson-Villari-Biancalana (RVB) method to provide a refined derivation of the Hawking temperature for two recently discovered topological black hole solutions. Previous calculations have shown inconsistencies when using traditional methods on such exotic horizons, necessitating a more comprehensive mathematical analysis.
By incorporating higher-order terms in the Laurent expansions of the metric functions near the horizon and utilizing the topological attributes defined by the Euler characteristic, we uncover additional corrections to the Hawking temperature that go beyond standard approaches. These findings highlight the intricate interplay between local geometry, spacetime topology, and quantum effects.
The results of our study address the discrepancies identified in earlier works, offering a more precise depiction of the thermodynamic properties associated with the black holes under investigation. Moreover, these findings have broader implications for the understanding of topological structures in advanced gravitational theories.
The Future Roadmap
Potential Challenges
- Verification and Validation: As with any theoretical work, it is crucial to validate the results through experimental verification or comparison with other mathematical models.
- Generalization: The application and extension of this refined derivation to other topological black hole solutions will be a challenge, as each solution may have its distinct characteristics and complexities.
- Physical Interpretation: The interpretation of the additional corrections to the Hawking temperature and their implications for the black holes’ physical behavior will require further investigation and understanding.
Opportunities on the Horizon
- Advancements in Gravitational Theories: The refined derivation presented in this paper opens up new avenues for exploring the interplay between topology, geometry, and quantum effects in gravitational theories. It may lead to the development of more comprehensive theories or refine existing ones.
- Improved Understanding of Exotic Horizons: The insights gained from this study will contribute to a better understanding of the thermodynamic properties and behavior of topological black holes. This knowledge can lead to advancements in fields such as black hole thermodynamics and cosmology.
- Broader Implications: The implications of our findings extend beyond the specific topological black hole solutions examined in this study. They may have implications for other physical systems with topological structures and shed light on the connection between topology and quantum effects in various scientific domains.
Note: This paper is accompanied by extensive mathematical derivations, which are not included in this summary for brevity. Please refer to the full paper for a detailed analysis.
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by jsendak | Mar 12, 2025 | GR & QC Articles
arXiv:2503.07679v1 Announce Type: new
Abstract: This paper investigates the thermodynamic properties of the coexistence region of two horizons in the charged 4-dimensional Einstein-Gauss-Bonnet (4D-EGB) spacetime. Initially, we apply the universal first law of thermodynamics to derive the corresponding thermodynamic quantities for the coexistence region between the black hole event horizon and the cosmological event horizon, subject to the relevant boundary conditions. Next we examine the thermal properties of the thermodynamic system described by these equivalent quantities. Our analysis reveals that the peak of the heat capacity as a function of temperature exhibits characteristics similar to those observed in a paramagnetic system under specific conditions. We further conclude that, under certain conditions, the heat capacity mirrors that of a two-level system formed by two horizons with distinct temperatures. By comparing the heat capacity of the 4D-EGB spacetime’s equivalent thermodynamic system with that of a two-level system defined by the two horizons in the spacetime, we can estimate the number of microscopic degrees of freedom at the two horizons. This findings sheds light on the quantum properties of de Sitter (dS) spacetime with two horizon interfaces and offers a novel approach to exploring the quantum properties of black holes and dS spacetime.
The Thermodynamic Properties of the Coexistence Region of Two Horizons in the Charged 4D-EGB Spacetime
This paper investigates the thermodynamic properties of the coexistence region between the black hole event horizon and the cosmological event horizon in the charged 4-dimensional Einstein-Gauss-Bonnet (4D-EGB) spacetime. By applying the universal first law of thermodynamics and considering the relevant boundary conditions, we derive the corresponding thermodynamic quantities for this coexistence region.
Thermal Properties of the Thermodynamic System
After obtaining the thermodynamic quantities, we examine the thermal properties of the system described by these equivalent quantities. Our analysis reveals that the heat capacity as a function of temperature exhibits characteristics similar to those observed in a paramagnetic system under specific conditions.
Heat Capacity Mirroring a Two-Level System
Furthermore, we conclude that, under certain conditions, the heat capacity mirrors that of a two-level system formed by the two horizons with distinct temperatures. This comparison of the heat capacity between the 4D-EGB spacetime’s equivalent thermodynamic system and the two-level system defined by the two horizons allows us to estimate the number of microscopic degrees of freedom at these horizons.
Roadmap for Future Investigations
The findings in this study shed light on the quantum properties of de Sitter (dS) spacetime with two horizon interfaces. Moving forward, there are several opportunities for further exploration:
- Quantum Properties of Black Holes: This research opens up a novel approach to exploring the quantum properties of black holes using the relation between heat capacity and two-level systems.
- Quantum Properties of dS Spacetime: The quantum properties of dS spacetime, especially with regards to the two horizon interfaces, offer interesting avenues for future investigations.
- Microscopic Degrees of Freedom: By estimating the number of microscopic degrees of freedom at the horizons, we can gain a better understanding of the underlying quantum nature of spacetime.
Potential Challenges
Despite the promising findings and opportunities, there are also challenges to address in future research:
- Validity of Assumptions: The conclusions of this study rely on certain assumptions and conditions. Further investigations should verify the validity of these assumptions and explore the robustness of the results.
- Quantum Gravity: Understanding the quantum properties of spacetime, including black holes and dS spacetime, requires a deeper understanding of quantum gravity. Integration with quantum gravity theories will be crucial for further progress.
- Experimental Verification: The findings in this study are theoretical in nature. Experimental verification or observational evidence will be necessary to validate the theoretical predictions.
In summary, this study explores the thermodynamic properties of the coexistence region between the black hole event horizon and the cosmological event horizon in the charged 4D-EGB spacetime. The analysis reveals similarities to paramagnetic systems and suggests that the thermodynamic system can be modeled as a two-level system. This opens up new avenues for investigating the quantum properties of black holes and dS spacetime. However, challenges such as verifying assumptions, integrating with quantum gravity, and experimental validation remain to be addressed in future research.
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by jsendak | Dec 20, 2024 | GR & QC Articles
arXiv:2412.14230v1 Announce Type: new
Abstract: We find an exact black hole solution for the Einstein gravity in the presence of Ay’on–Beato–Garc’ia non-linear electrodynamics and a cloud of strings. The resulting black hole solution is singular, and the solution becomes non-singular when gravity is coupled with Ay’on–Beato–Garc’ia non-linear electrodynamics only. This solution interpolates between Ay’on–Beato–Garc’ia black hole, Letelier black hole and Schwarzschild black hole { in the absence of cloud of strings parameter, magnetic monopole charge and both of them, respectively}. We also discuss the thermal properties of this black hole and find that the solution follows the modified first law of black hole thermodynamics. Furthermore, we estimate the solution’s black hole shadow and quasinormal modes.
Conclusion
The article presents an exact black hole solution for the Einstein gravity in the presence of Ay’on–Beato–Garc’ia non-linear electrodynamics and a cloud of strings. The solution is initially singular but becomes non-singular when gravity is coupled with Ay’on–Beato–Garc’ia non-linear electrodynamics only. This solution connects Ay’on–Beato–Garc’ia black hole, Letelier black hole, and Schwarzschild black hole in different scenarios. The thermal properties of the black hole are discussed, and it follows the modified first law of black hole thermodynamics. Additionally, the article estimates the black hole shadow and quasinormal modes of the solution.
Future Roadmap
Potential Challenges
- One potential challenge in the future is to further investigate the singularity of the black hole solution and understand its physical implications.
- It would be valuable to explore the behavior of the black hole solution under different scenarios, such as considering the presence of magnetic monopole charge or a cloud of strings parameter.
- Another challenge is to validate the results experimentally or through observational data.
Potential Opportunities
- Further research can be conducted to understand the relationship between Ay’on–Beato–Garc’ia non-linear electrodynamics and the non-singularity of the black hole solution.
- The modified first law of black hole thermodynamics observed in this solution opens up opportunities for exploring the thermodynamic properties of other exact black hole solutions.
- The estimation of the black hole shadow and quasinormal modes can be improved and refined, providing more accurate predictions for future observations.
In conclusion, the article presents an intriguing exact black hole solution with interesting properties. The future roadmap involves addressing potential challenges related to the singularity, conducting further investigations under different scenarios, and validating the results. Additionally, there are exciting opportunities to explore the relationship between Ay’on–Beato–Garc’ia non-linear electrodynamics and non-singularity, study the thermodynamic properties of other black hole solutions, and refine estimations of the black hole shadow and quasinormal modes.
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