It is commonly believed that the dRGT theory is the unique way to describe a massive spin-2 field without ghosts. While dRGT is arguably the most elegant massive gravity theory, it seems that it may not be the unique ghost-free one if one relaxes the assumption of locality. In this work, we derive a new massive gravity theory by using a disformal transformation of the metric tensor in the dRGT action. Its decoupling limit lives inside the class of beyond-Horndeski Lagrangians as long as the transformation of the metric remains purely disformal. This proves the absence of ghosts in this decoupling limit and hints at their absence in the whole theory. One caveat, however, is the possible nonlocal structure of this new theory. Furthermore, we consider a more general case, in which we allow the conformal factor in the disformal transformation to be different from unity, and discuss the absence of ghosts in this decoupling limit.
In the context of the dRGT massive gravity coupled with nonlinear electrodynamics, we present new dRGT black hole solutions. Together with the thermodynamical properties of the solutions, we study the greybody factor of the corresponding black hole solution. To this end, we compute the rigorous bound on the greybody factor for the obtained dRGT black holes. The obtained results are graphically represented for different values of the theory's physical parameters. Our analysis shows that the charged dRGT black holes of nonlinear electrodynamics evaporate quicker than the charged dRGT black holes…
An interesting proposal has recently been made to extend massive gravity models beyond dRGT by a disformal transformation of the metric. In this Letter we want to note that it can be viewed as a mimetic extension of dRGT gravity which enormously simplifies the Hamiltonian analysis. In particular, pure gravity sector is equivalent to the usual dRGT gravity coupled to a constrained scalar field. And we also give some comments about possible matter couplings.
Charged scalar perturbations on charged black holes in dRGT massive gravity
研究了dRGT大质量引力场中一类带电黑洞中大质量带电标量场的准定态分布。我们讨论了度规中的线性项是dRGT质量引力的一个独特性质，它是如何影响时空结构的。对dRGT黑洞背景中带电标量场的准正规模进行了数值计算。对于渐近de Sitter（dS）黑洞，利用改进的渐近迭代法得到了相应的拟正规频率.对于$\ell=0$情形，发现了不稳定模，其实部满足超辐射条件。对于$\ell=2$，结果表明，所有的de Sitter黑洞在小扰动下都是稳定的.对于渐近dRGT anti de Sitter（AdS）黑洞，发现了频率满足超辐射条件的不稳定模.讨论了质量重力参数的影响。解析计算揭示了具有线性项的质量引力模型中准正规模的独特扩散性质。数值结果证实了在dS和AdS的情况下存在的特征扩散模式。
The greybody factor of the massive Dirac field around the black hole in the dRGT massive gravity theory is investigated using the rigorous bound and the WKB approximation methods. In both methods, the greybody factor significantly depends on the shape of the potential. If the potential is smaller, there is more probability for the Dirac field to transmit through the black hole, therefore, the greybody factor is higher. Moreover, there exists a critical mass of the Dirac field such that the greybody factor is maximum. By comparing the results from these two methods, we argue that it is useful t…
The recent Event Horizon Telescope (EHT) observations of the M87* have led to a surge of interest in studying the shadow of black holes. Besides, investigation of time evolution and lifetime of black holes helps us to veto/restrict some theoretical models in gravitating systems. Motivated by such exciting properties, we study optical features of black holes, such as the shadow geometrical shape and the energy emission rate in modified gravity. We consider a charged AdS black hole in dRGT massive gravity and look for criteria to restrict the free parameters of the theory. The main goal of this …
In this work, we study the thin-shell wormholes in dRGT massive gravity. In order to joint two bulks of the spacetime geometry, we first derive junction conditions of the dRGT spacetime. This results the dynamics of the spherical thin-shell wormholes in the dRGT theory. We show that the massive graviton correction term of the dRGT theory in the Einstein equation is represented in terms of the effective anisotropic pressure fluid. However, if there is only this correction term, without invoking exotic fluids, we find that the thin-shell wormholes can not be stabilized. We then examine the stabi…
Although the dRGT massive gravity successfully explains the late-time cosmic acceleration, it cannot justify inflation. On the other hand, and in the frameworks of General Relativity and modified gravity, the interests and attempts to describe dark energy and inflation by using Lagranginas, which may have pole, have recently been enhanced. Subsequently, we are going to show that this kind of Lagrangian may justify inflation in the framework of dRGT massive gravity. The study is done focusing on the power and exponential potentials, and the results show a plausible consistency with the Planck 2…
The greybody factor from the black string in the de Rham-Gabadadze-Tolley (dRGT) massive gravity theory is investigated in this study. The dRGT massive gravity theory is one of the modified gravity theories used in explaining the current acceleration in the expansion of the universe. By using cylindrical symmetry, black strings in dRGT massive gravity are shown to exist. When quantum effects are taken into account, black strings can emit thermal radiation called Hawking radiation. The Hawking radiation at spatial infinity differs from that at the source by the so-called greybody factor. In thi…
We introduce the cosmological analysis of the Dirac-Born-Infeld dRGT massive gravity theory which is a new extension of de Rham-Gabadadze-Tolley (dRGT) massive gravity. In this theory, we consider the Dirac-Born-Infeld (DBI) scalar field which is coupled to the graviton field. Moreover, we perform the cosmological background equations, and we demonstrate the self-accelerating background solutions. We show that the theory consists of self-accelerating solutions with an effective cosmological constant. In the following, we exhibit tensor perturbations analyses and achieve the dispersion relation…
The Bardeen black hole solution is the first spherically symmetric regular black hole based on the Sakharov and Gliner proposal which is a modification of the Schwarzschild black hole. We present the Bardeen black hole solution in the presence of the de Rham, Gabadaadze, and Tolly (dRGT) massive gravity, which is regular everywhere in the presence of a nonlinear source. The obtained solution reduces to the Bardeen black hole in the absence of a massive gravity parameter, and the Schwarzschild black hole when magnetic charge $g = 0$. We investigated the thermodynamic quantities, that is, mass (…
We study the static and spherical symmetric (SSS) configurations in the non-minimal model of the de Rham-Gabadadze-Tolley (dRGT) massive gravity with a flat reference metric. Considering the modified Tolman-Oppenheimer-Volkoff (TOV) equation, the Bianchi identity, and energy-momentum conservation, we find a new algebraic equation for the radial coordinate of the reference metric. We demonstrate that this equation suggests an absence of the Vainshtein mechanism in the minimal model of the dRGT massive gravity, while it has two branches of solutions where one connects with the Schwarzschild spac…
We show the analysis of a thin accretion disk around a static and spherically symmetric black hole in dRGT massive gravity. We present the accretion disk analysis in a gravitational theory with a nonzero graviton mass. Also, we study the event horizons of the black hole and we calculate the equations of motion and effective potential. In the following, we obtain the specific energy, specific angular momentum, and angular velocity of the particles which move in circular orbits. In addition, we plot the effective potentials for two cases and we show the locations of stable circular orbits. At la…
In this note we propose a topological action for a Poincare times diffeomorphism invariant gauge theory. We show that there is Higgs phase where the gauge symmetry is spontaneous broken to a diagonal Lorentz subgroup and gives the Einstein-Hilbert action plus the dRGT potential terms. In this vacuum, there are five (three from Goldstone modes) propagating degrees of freedom which form polarizations of a massive spin 2 particle, an extra healthy heavy scalar (Higgs) mode and no Boulware-Deser ghost mode. We further show that the action can be derived in a limit from a topological de Sitter inva…
The tunneling behavior of fermions with half-integral spin from a higher dimensional charged anti-de Sitter (AdS) black hole in de Rham, Gabadadze and Tolley (dRGT) massive gravity is investigated via a modified Hamilton-Jacobi equation. The results demonstrate that the modified thermodynamic quantities not only are related to the properties of the higher dimensional charged AdS black hole in dRGT massive gravity but also depend on the parameter $β$, the coupling constant $σ$ and the mass of emitted particles $m$. In addition, the modified Hawking temperature is higher than the original temper…
We consider the mass-radius bounds for spherically symmetric static compact objects in the de Rham-Gabadadze-Tolley (dRGT) Massive Gravity theories, free of ghosts. In this type of gravitational theories the graviton, the quantum of gravity, may have a small, but non-vanishing mass. We derive the hydrostatic equilibrium and mass continuity equations in the Lorentz-violating Massive gravity in the presence of a cosmological constant and for a non-zero graviton mass. The case of the constant density stars is also investigated by numerically solving the equilibrium equations. The influence of the…
Massive gravity theory introduced by de Rham, Gabadadze, Tolley (dRGT) is restricted by several uniqueness theorems that protect the form of the potential and kinetic terms, as well as the matter coupling. These restrictions arise from the requirement that the degrees of freedom match the expectation from Poincaré representations of a spin--2 field. Any modification beyond the dRGT form is known to invalidate a constraint that the theory enjoys and revive a dangerous sixth mode. One loophole is to exploit the effective nature of the theory by pushing the sixth mode beyond the strong coupling s…
Quasi Normal Modes and P-V Criticallity for scalar perturbations in a class of dRGT massive gravity around Black Holes
利用改进的渐进迭代方法（Improved AIM）研究一类dRGT大质量引力中的黑洞的中性和带电准简正模（QNM）及其热力学行为。研究了中性和带电dRGT黑洞在无质量标量微扰下不同质量参数m_g下的QNM。随着m_g的增大，准简正频率的幅值也增大.并与Schwarzchild de Sitter（SdS）的情况进行了比较。本文还研究了在de Sitter空间中质量标量微扰下上述黑洞的P-V临界性。研究发现，中性黑洞的热力学行为不表现出物理上可行的相变，而带电黑洞则表现出一定的相变。
One of the solutions of Einstein field equation with cylindrical symmetry is known as black string solution. In this work, the rotating black string solution in dRGT massive gravity is obtained and then called rotating-dRGT black string solution. This solution is a kind of generalized version of rotating AdS/dS black sting solution containing an additional two more terms characterizing the structure of graviton mass. The horizon structures of the black string are explored. The thermodynamical properties of the black string are investigated. We found that it is possible to obtain the Hawking-Pa…
In this report, we discuss the behavior of coordinate-time dependent lapse function of FLRW metric of an accelerated expanding universe in the de Rham-Gabadadze-Tolley massive gravity theory. We find for the conventional dRGT formalism the corresponding lapse function can exhibit unphysical behaviors in the associated parameter space with a negative cosmological-constant-like term that leads to the decelerated universe model. To solve this problem, we introduce the so-called cosmological background density parameter to the perfect fluid stress-energy tensor which induces negative pressure. It …
The linear theory of massive spin-two field in arbitrary curved background is investigated. In flat spacetime, the Fierz-Pauli model is well-known as the unique linear theory describing the massive spin-two field. On the other hand, in order to construct the massive spin-two theory in fixed curved background with arbitrary metric, infinite series of nonminimal coupling terms are necessary. In [Nucl. Phys. B 584 (2000) 615], Buchbinder et al. have derived the condition for the ghost-freeness and they have solved the condition in small curvature approximation. In the leading order approximation,…
The thermodynamic properties of the de Rham-Gabadadze-Tolley (dRGT) black hole in the asymptotically de Sitter (dS) spacetime are investigated by using Rényi entropy. It has been found that the black hole with asymptotically dS spacetime described by the standard Gibbs-Boltzmann statistics cannot be thermodynamically stable. Moreover, there generically exist two horizons corresponding to two thermodynamic systems with different temperatures, leading to a nonequilibrium state. Therefore, in order to obtain the stable dRGT black hole, we use the alternative Rényi statistics to analyze the thermo…
In this study, we demonstrate the use of physics-informed neural networks (PINNs) for computing the quasinormal modes (QNMs) of black holes in de Rham-Gabadadze-Tolley (dRGT) massive gravity. These modes describe the oscillation frequencies of perturbed black holes and are important in understanding the behavior of these objects. We show that by carefully selecting the hyperparameters of the PINN, including the network architecture and the training data, it is possible to achieve good agreement between the computed QNMs and the approximate analytical formula in the near-extremal limit for the …
三维空间中的大质量引力有几种不同的表述。最近，Bergshoeff { \it et al.}研究了一阶形式的三维双重力dRGT模型Zwei-Dreibein引力。有人认为Boulware-Deser模式被额外的约束所扼杀。我们重新审视这一论断，并得出结论，有部门的空间的初始条件，或子集的最一般的这样的模型，这种模式是缺席。但是，一般来说，该理论确实具有3个自由度，因此Boulware-Deser模式仍然有效。我们的结果也揭示了dRGT模型的度量和vierbein公式之间的等价性。
We investigate gravitational lensing and particle motions around non-asymptotically flat black hole spacetime in non-linear, ghost-free massive gravity theory, called de Rham-Gabadadze-Tolley (dRGT) massive gravity. Deflection angle formulae are derived in terms of perihelion parameter. The deflection angle can be positive, zero or even negative with various perihelion distance. The negative angle reveals repulsive behaviour of gravity from a linear term $γ$ in the dRGT black hole solution. We also find an analytically approximated formula of deflection angle in two regimes: large and small $γ…
It is known that de Rham-Gabadadze-Tolley (dRGT) massive gravity does not permit a homogeneous and isotropic universe with flat or spherical spatial metrics. We demonstrate that a singular reference metric solves this problem in an economic and straightforward way. In the dRGT massive gravity with a singular reference metric, there are sound homogeneous and isotropic cosmological solutions. We investigate cosmologies with the static and dynamical singular reference metrics, respectively. The term like dark energy appears naturally and the universe accelerates itself in some late time evolution…
In this paper we study the possibility of assigning a geometric structure to the Lie groups. It is shown the Poincaré and Weyl groups have geometrical structure of the Riemann-Cartan and Weyl space-time respectively. The geometric approach to these groups can be carried out by considering the most general (non)metricity conditions, or equivalently, tetrad postulates which we show that can be written in terms of the group's gauge fields. By focusing on the conformal group we apply this procedure to show that a nontrivial 3-metrics geometry may be extracted from the group's Maurer-Cartan structu…
As massive gravity and its extensions offer physically well-defined gravitational theories with a nonzero graviton mass, we present a new extension of the de Rham-Gabadadze-Tolley (dRGT)massive gravity, which is tachyonic massive gravity theory. We firstly introduce the new extension of the dRGT massive gravity, constructed by adding a tachyonic term. We then find the cosmological background equations, and present the analysis of self-accelerating solutions. We examine the tensor perturbations to calculate the dispersion relation of gravitational waves (GWs). In a special case, we consider a c…
Thermodynamics and phase transitions of charged-AdS black holes in dRGT massive gravity with nonlinear electrodynamics
Centre for Theoretical Physics, Jamia Millia Islamia（贾米亚米利亚伊斯兰大学理论物理中心）；Institute for Theoretical Physics and Cosmology, Zhejiang University of Technology（浙江工业大学理论与宇宙学研究所）；Phenikaa Institute for Advanced Study, Phenikaa University（菲尼亚卡大学高级研究院）；Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal（夸祖鲁-纳塔尔大学数学、统计与计算机科学学院天体物理与宇宙学研究单元）
If the kinetic interactions of a Lorentz-invariant massive graviton are Einstein-Hilbert, then the only possible potential terms free from the Boulware-Deser ghost are those of de Rham, Gabadadze and Tolley (dRGT). We point out there are other possibilities if the kinetic terms are not required to be Einstein-Hilbert. We construct pseudo-linear ghost-free potentials, terms that derive in a natural way from the linear theory. The simplicity of this approach allows us to construct diffeomorphism non-invariant higher-derivative interaction terms that do not introduce ghosts. We conjecture that th…
