arXiv subjects

Meng-Sen Ma

Publications and source records attributed to Meng-Sen Ma.

At least 19 recordsLinked to original sources

arXiv2026

Thermodynamic phase structure and topological charge of Hayward-AdS black holes under phase space constraints

We investigate the thermodynamic behavior of the Hayward-AdS black hole and compare it with its singular counterpart from which it can be constructed through the imposition of an additional constraint. The singular black hole displays a rich phase structure, including reentrant phase transitions reminiscent of those observed in higher-dimensional Kerr-AdS spacetimes. After the constraint is imposed, the resulting Hayward-AdS black hole continues to exhibit Van der Waals-type $P-V$ criticality. However, its Gibbs free energy profile differs qualitatively from that of standard RN-AdS black holes. In addition, we extend the analysis by employing thermodynamic topology to characterize the global structure of the phase space. We find that the topological charge of the singular black hole is $-1$, whereas that of the Hayward-AdS black hole becomes $+1$. This change of topological charge indicates that the constraint not only regularizes the geometry but also induces a qualitative transformation in the thermodynamic configuration space.

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arXiv2025

From singular to regular: revisiting thermodynamics of Bardeen-AdS black holes

We explore the thermodynamic properties of the regular Bardeen-AdS black hole obtained by imposing an additional constraint on a singular "mother" black hole. This constraint eliminates the physical singularity but leads to the breakdown of the standard first law of black hole thermodynamics. The singular black hole exhibits a reentrant phase transition similar to that of the higher-dimensional Kerr-AdS black hole. The Bardeen-AdS black hole exhibits $P-V$ criticalities similar to that of the RN-AdS black hole, however has striking differences in its Gibbs free energy behavior. In particular, the characteristic "swallow-tail" structure associated with first-order phase transitions disappears. Instead, an "8-shaped" or "c-shaped" structure occurs, signifying a first-order phase transition or a zeroth-order phase transition between the small black hole and the large black hole phases, respectively. Our analysis suggests that constraint-induced modifications in the thermodynamic phase space may have deep consequences for the critical behaviors of black holes.

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arXiv2025

Universal relations with the non-extensive entropy in the RPS and CFT framework

In this paper, an in-depth investigation of the thermodynamic relations for AdS Reissner-Nordstr$\ddot{o}$m black holes immersed in perfect fluid dark matter (PFDM) is presented. This investigation is conducted within both the restricted phase space (RPS) and the conformal field theory (CFT) frameworks. The influence of non-extensive forms of entropy is also systematically examined. Our results demonstrate that the Goon-Penco (GP) relation for charged AdS black holes holds within both the RPS and CFT frameworks, irrespective of the specific form of entropy modification. The conclusion of the present study demonstrates that the GP relation constitutes a universal thermodynamic relation.

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arXiv2025

High-order QED correction impacts on phase transition of the Euler-Heisenberg dS spacetime

Recent studies have demonstrated that AdS black holes possess the basic characteristics of a standard thermodynamic system. Concurrently, the thermodynamic properties of spacetimes featuring multiple horizons with distinct radiation temperatures have also attracted research interest. In this work, considering the high-order quantum electrodynamics (QED) correction, we initially establish an equivalent thermodynamic system for the coexistence region of black hole and cosmological horizons. On this basis, we conduct a detailed investigation into the thermodynamic properties of this dual-horizon coexistence region. Our results demonstrate that this equivalent thermodynamic system exhibits van der Waals-like thermodynamic behavior. Furthermore, we introduce a nonlinear parameter $\gamma$ to analyze its impact on phase transitions within the equivalent thermodynamic system. Under specific conditions, the system undergoes first- or second-order phase transitions for $\gamma=0$, and zeroth- or second-order phase transitions for $\gamma\neq0$. Finally, by utilizing the generalized off-shell Helmholtz free energy within the thermodynamic topological framework for black holes, we extend this methodology to investigate the topological properties of de Sitter (dS) spacetime. We compute the topological number characterizing the coexistence region of dual horizons in Euler-Heisenberg (EH) dS spacetime using equivalent thermodynamic state parameters. Additionally, we investigate the influence of the nonlinear parameter $\gamma$ on the thermodynamic characteristics of the equivalent system.

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arXiv2025

Thermodynamic relation on rotating charged black strings with arbitrary cosmological constant

The Goon-Penco (GP) relation was investigated on rotating charged black strings with an arbitrary cosmological constant. It has been demonstrated that the GP relation retains its form in the context of spacetimes described by cylindrical coordinates. In addition, the GP relation is derived in scenarios where the energy state parameters (including angular momentum $J$ and charge $Q$, etc.) are expressed as functions of the perturbation parameter $\eta$. This finding indicates that the GP relation is not only valid for spacetimes described by spherically symmetric coordinates, but also prevalent for non-spherically symmetric spacetimes, such as cylindrical coordinates. Therefore, the present study demonstrated that the GP relation is universal for spacetimes with arbitrary cosmological constants, irrespective of the adopted coordinate system.

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arXiv2025

Regular black holes and reductions of thermodynamic phase spaces

The thermodynamic inconsistency observed in regular black holes is resolved through the framework of reduced thermodynamic phase spaces. We demonstrate that regular black holes are essentially induced from singular black holes by adding an extra requirement, which imposes a constraint among black hole parameters. This constraint reduces the thermodynamic phase space, rendering the standard form of the first law of black hole thermodynamics inapplicable. Accordingly, we propose a novel methodology to study the thermodynamic properties of regular black holes. Thermodynamic quantities must be defined in the full, unconstrained thermodynamic phase space of the underlying singular black holes, only afterward is the constraint imposed to derive the consistent and meaningful thermodynamic quantities of the regular black holes. Crucially, this framework extends beyond regular black holes and applies universally to any black hole with this kind of constraint.

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arXiv2022

Fractional phase transitions of RN-AdS black hole at Davies points

We perform a study of phase transitions of RN-AdS black hole at its Davies points according to a generalized Ehrenfest classification of phase transition established on the basis of fractional derivatives. Davies points label the positions where heat capacity diverges. According to the usual Ehrenfest classification, second-order phase transitions occur there. For RN-AdS black hole, the Davies points can be classified into two types. The first type corresponds to the extreme values of temperature and the second type corresponds to the infection point(namely the critical point) of temperature. Employing the generalized Ehrenfest classification, we find that the orders of phase transition at the two types of Davies points are different. It is $3/2$-order for the first type and $4/3$-order for the second type. Thus this finer-grained classification can discriminate phase transitions that are supposed to be in the same category, which may provide some new insights toward a better understanding of black hole thermodynamics.

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arXiv2022

Barrow black holes and the minimal length

Following Barrow's idea of fractal black hole horizon, we re-derive black hole entropy of static spherically symmetric black holes. When a black hole absorbs matter its horizon area will increase. Given the spherically fractal structure, we conjecture that the minimal increase of the horizon area should be the area of the smallest bubble sphere. From this, we find the black hole entropy has a logarithmic form, which is similar to that of Boltzmann entropy if we consider $A/A_{pl}$ as the number of microscopic states. We further calculate temperatures and heat capacities of Schwarzschild, Reissner-Nordstr{ö}m(RN), and RN-AdS black holes. It is found that their temperatures are all monotonically increasing and the heat capacities are all positive, which means these black holes are thermodynamically stable. Besides, for RN-AdS black hole we find its heat capacity has Schottky anomaly-like behavior, which may reflect the existence of the discrete energy level and restricted microscopical degree of freedom.

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arXiv2019

Fractional-order phase transition of charged AdS black holes

Employing the fractional derivatives, we construct a more elaborate classification of phase transitions compared to the original Ehrenfest classification. In this way, a thermodynamic system can even undergo a fractional-order phase transition. We use this method to restudy the charged AdS black hole and Van der Waals fluids and find that at the critical point they both have a $4/3$-order phase transition, but not the previously recognized second-order one.

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arXiv2018

Phase transitions of GUP-corrected charged AdS black hole

We study the thermodynamic properties and critical behaviors of the topological charged black hole in AdS space under the consideration of the generalized uncertainty principle (GUP). It is found that only in the spherical horizon case there are Van der Waals-like first-order phase transitions and reentrant phase transitions. From the equation of state we find that the GUP-corrected black hole can have one, two and three apparent critical points under different conditions. However, it is verified by the Gibbs free energy that in either case there is at most one physical critical point.

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arXiv2018

Entropy of Kerr-de Sitter black hole

Based on the consideration that the black hole horizon and the cosmological horizon of Kerr-de Sitter black hole are not independent each other, we conjecture the total entropy of the system should have an extra term contributed from the correlations between the two horizons, except for the sum of the two horizon entropies. By employing globally effective first law and effective thermodynamic quantities, we obtain the corrected total entropy and find that the region of stable state for kerr-de Sitter is related to the angular velocity parameter $a$, i.e., the region of stable state becomes bigger as the rotating parameters $a$ is increases.

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arXiv2017

$(2+1)$-dimensional regular black holes with nonlinear electrodynamics sources

On the basis of two requirements: the avoidance of the curvature singularity and the Maxwell theory as the weak field limit of the nonlinear electrodynamics, we find two restricted conditions on the metric function of $(2+1)$-dimensional regular black hole in general relativity coupled with nonlinear electrodynamics sources. By the use of the two conditions, we obtain a general approach to construct $(2+1)$-dimensional regular black holes. In this manner, we construct four $(2+1)$-dimensional regular black holes as examples. We also study the thermodynamic properties of the regular black holes and verify the first law of black hole thermodynamics.

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arXiv2017

Noncommutative geometry inspired black holes in Rastall gravity

Under two different metric ansatzes, the noncommutative geometry inspired black holes (NCBH) in the framework of Rastall gravity are derived and analyzed. We consider the fluid-type matter with the Gaussian-distribution smeared mass density. Taking a Schwarzschild-like metric ansatz, it is shown that the noncommutative geometry inspired Schwarzschild black hole (NCSBH) in Rastall gravity, unlike its counterpart in general relativity (GR), is not a regular black hole. It has at most one event horizon. After showing a finite maximal temperature, the black hole will leave behind a point-like massive remnant at zero temperature. Considering a more general metric ansatz and a special equation of state of the matter, we also find a regular NCBH in Rastall gravity, which has a similar geometric structure and temperature to that of NCSBH in GR.

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arXiv2017

Peculiar $P-V$ criticality of topological Hořava-Lifshitz black holes

We demonstrate the existence of $P-V$ criticality of the topological Hořava-Lifshitz(HL) black holes with a spherical horizon $(k=1)$ in the extended phase space. With the electric charge, we find that the critical behaviors of the HL black hole are nearly the same as those of van der Waals(VdW) system. For the uncharged case, the HL black hole has a peculiar $P-V$ criticality. The critical behavior is completely controlled by a parameter $ε$, but not the temperature $T$. When $ε$ is larger than a critical value $ε_c$, no matter what the temperature is, there will be the first-order phase transition. Moreover, we find that there is an infinite number of critical points which form a "critical curve". As far as we know, this is the first time to find this kind of peculiar $P-V$ criticality.

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arXiv2017

Phase transition and thermodynamic stability of topological black holes in Hořava-Lifshitz gravity

On the basis of horizon thermodynamics, we study the thermodynamic stability and $P-V$ criticality of topological black holes constructed in Hořava-Lifshitz (HL) gravity without the detailed-balance condition (with general $ε$). In the framework of horizon thermodynamics, we do not need the concrete black hole solution (the metric function) and the concrete matter fields. It is shown that the HL black hole for $k=0$ is always thermodynamically stable. For $k=1$, the thermodynamic behaviors and $P-V$ criticality of the HL black hole are similar to those of RN-AdS black hole for some $ε$. For $k=-1$, the temperature is classified into six types by their different features. Among them, we mainly focus on the type with triply degenerate thermodynamic state. It is also shown that there is a "thermodynamic singularity" for the $k=-1$ HL black hole, where the temperature and Gibbs free energy both diverge apart from a special pressure $P_s$.

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arXiv2017

Horizon thermodynamics in fourth-order gravity

In the framework of horizon thermodynamics, the field equations of Einstein gravity and some other second-order gravities can be rewritten as the thermodynamic identity: $dE=TdS-PdV$. However, in order to construct the horizon thermodynamics in higher-order gravity, we have to simplify the field equations firstly. In this paper, we study the fourth-order gravity and convert it to second-order gravity via a so-called " Legendre transformation " at the cost of introducing two other fields besides the metric field. With this simplified theory, we implement the conventional procedure in the construction of the horizon thermodynamics in 3 and 4 dimensional spacetime. We find that the field equations in the fourth-order gravity can also be written as the thermodynamic identity. Moreover, we can use this approach to derive the same black hole mass as that by other methods.

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arXiv2016

Thermodynamic properties of black holes in de Sitter space

We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black hole and Reissner-Nordström-de Sitter (RNdS) black hole in the view of global and effective thermodynamic quantities. Making use of the effective first law of thermodynamics, we can derive the effective thermodynamic quantities of de Sitter black holes. It is found that these effective thermodynamic quantities also satisfy Smarr-like formula. Especially, the effective temperatures are nonzero in the Nariai limit, which is consistent with the idea of Bousso and Hawking. By calculating heat capacity and Gibbs free energy, we find SdS black hole is always thermodynamically stable and RNdS black hole may undergoes phase transition at some points.

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arXiv2016

Entropy of Reissner-Nordström-de Sitter black hole

Based on the consideration that the black hole horizon and the cosmological horizon of Reissner-Nordström black hole in de Sitter space are not independent each other, we conjecture the total entropy of the system should have an extra term contributed from the entanglement between the two horizons, except for the sum of the two horizon entropies. Making use of the globally effective first law and the effective thermodynamic quantities, we derive the total entropy and find that it will diverge as the two horizons tends to coincide.

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