Gravity's Rainbow Research Articles

Joule–Thomson expansion in charged AdS black hole surrounded by a cosmological fluid in Rainbow Gravity

In this work, we analyze the Joule–Thomson expansion in an AdS Reissner–Nordström black hole, surrounded by an average cosmological fluid, in Rainbow Gravity. We plot the graphs corresponding to the inversion temperature curves and numerically calculate the ratio between the minimum of the inversion temperature and the critical temperature, with the aim of investigating how Rainbow Gravity alters such behaviors compared to General Relativity.

Klein–Gordon oscillator in a global monopole space–time with rainbow gravity

Klein–Gordon oscillator in a global monopole space–time with rainbow gravity

Interaction of the generalized Duffin–Kemmer–Petiau equation with a non-minimal coupling under the cosmic rainbow gravity

In this study, we survey the generalized Duffin–Kemmer–Petiau oscillator containing a non-minimal coupling interaction in the context of rainbow gravity in the presence of the cosmic topological defects in space-time. In this regard, we intend to investigate relativistic quantum dynamics of a spin-0 particle under the modification of the dispersion relation according to the Katanaev–Volovich geometric approach. Thus, based on the geometric model, we study the aforementioned bosonic system under the modified background by a few rainbow functions. In this way, by using an analytical method, we acquire energy eigenvalues and corresponding wave functions to each scenario. Regardless of rainbow gravity function selection, the energy eigenvalue can present symmetric, anti-symmetric, and symmetry breaking characteristics. Besides, one can see that the deficit angular parameter plays an important role in the solutions.

Quantum dynamics of photon in rainbow gravity

In the present article, quantum dynamics of the photon is investigated in the cosmic string spacetime via gravity’s rainbow. We solve the mDKP (massless Duffin–Kemmer–Petiau) equation exactly and obtain the energy spectrum of photon. Then, we solve the Maxwell equations in the same gravity’s rainbow background and show that the solutions obtained are equivalent to the results of the photon equation. The energy spectrum of the photon is analyzed for three different rainbow functions.

Relativistic quantum dynamics of scalar particles in the rainbow formalism of gravity

In the present article, we investigate the Klein–Gordon equation (KGE) in a topologically trivial Gödel-type space-time in the context of rainbow gravity (RG). Exact solutions and energy spectrum of scalar particles are obtained for the considered model. Also, the same systems are studied with the existence of the Klein–Gordon oscillator (KGO) potential. Results are evaluated by considering two different rainbow functions and they are analyzed graphically. We observe that the energy spectrum of scalar particles is modified by rainbow functions compared to the solutions obtained via the ordinary general relativity (GR) theory.

Correlations between emission events in Rainbow Gravity

In this work, we study emission correlations in Rainbow Gravity (RG) black holes known to have black hole remnants. Non-thermal corrections are responsible for generating non-zero correlations between particle emission events during the black hole evaporation process. With this in mind, we calculate the temperatures considering back-reaction effects. Then, we obtain the correlations between emission events for a RG metric proposed by Magueijo and Smolin. We also discuss through a numerical analysis the emission correlations behavior in the last stages of evaporation of the black hole.

Forming Ecomasculinities through Deep Ecology in Gravity's Rainbow

This article examines the concept of ecomasculinity--how masculinities and ecologies interact--through the lens of deep ecology, arguing (following Serpil Oppermann) that Pynchon's postmodernist boundary collapsing informs deep-ecological interconnections for male characters previously embroiled in negative cycles of patriarchal dominance. Ecomasculinity is an important emerging concept within ecocriticism, and recognising links between the positive iterations of masculinity and ecology that the ecomasculine seeks to express and the philosophy of deep ecology furthers the conversation about the utility of deep ecology to contemporary society.

New class of solutions in f(R)-gravity's rainbow and f(R)-gravity: Exact solutions+thermodynamics+quasinormal modes

This paper is devoted to the obtaining of the exact solutions in the framework of modified f(R)-gravity's rainbow(UV completion of General Relativity)/f(R)-gravity and the study of their thermodynamic behavior. In the f(R)-gravity's rainbow, we have analyzed the concept of effective potential barrier by transforming the radial equation of motion into standard Schrodinger form (we should note that scalar field Ψ(x) couples to gravity minimally or non-minimally with coupling constant λ and the gravity representation which is coupled with the scalar field is f(R) not just R). The most important result derived from this study is that gravity's rainbow increases the height of this potential in the exterior region of the event horizon. We also figure out the effect of the coupling constant λ and the f(R) parameter η on the height of the potential barrier and the other thermodynamical quantities like temperature and heat capacity. We have shown that the effect of f(R)-gravity on the temperature adds a coefficient of 1/2 to the cosmological constant.1 We study the quasinormal modes (QNMs) of 3D black holes in the f(R)-gravity's rainbow. For this purpose, we use the WKB approximation method upto third order corrections. We have shown the perturbations decay in corresponding diagrams when the coupling constant λ and rainbow function g(ε) change. We also obtain two different solutions when Ricci scalar is constant. The first one is for a charged slowly rotating toroidal black holes and the second one is for a higher dimensional toroidal black holes inspired by non-commutative geometry. The source for the second one is given by a fluid-type matter with the Gaussian-distribution smeared mass density. In Starobinsky model we show that the charged slowly rotating solution is ill-defined for s2=1 value.

Information paradox for a collapsing string cloud in rainbow gravity

This work is devoted to study the gravitational collapse of a string cloud in Rainbow gravity. The results are obtained for spherically symmetric spacetime. The radius and time to reach the horizon for a particle are calculated. This helps to understand the famous information paradox in the Early Universe and the intersteller gas clouds. Our study strengthens the view that the information can be carried out of the black hole as a result of the spherical collapse.

Exponentially charged dilaton black holes in rainbow gravity

The explicit form of the field equations has been obtained by varying the action of the four-dimensional Einstein-dilaton gravity in the presence of the scalar-coupled exponential nonlinear electrodynamics. The exact black hole solutions of the field equations have been obtained in an energy-dependent spherically symmetric geometry. It has been found that the solution of the scalar field equation can be obtained by combining two Liouville potentials. We have introduced three types of exponentially charged dilatonic black holes and their thermodynamic properties have been studied noting the effects of rainbow functions. The impacts of rainbow functions on the conserved and thermodynamic quantities of the new black hole solutions have been explored. Through the Smarr mass formula, it has been demonstrated that the first law of black hole thermodynamics remains valid for either of the new rainbow black hole solutions. The quantum gravitational effects on the thermodynamic phase transition or thermal stability of the black holes have been studied by use of the canonical ensemble method. By calculating the black hole heat capacity, the type-1 and type-2 phase transition points and the conditions under which the exponentially charged rainbow black holes are locally stable have been identified.

Regular black holes in Rainbow Gravity

In this work, we consider that in energy scales near to the Planck energy, the geometry, mass, speed of light, the Newtonian constant of gravitation and matter fields will depend on the energy. This type of theory is known as Rainbow Gravity. We coupled the nonlinear electrodynamics to the Rainbow Gravity, defining a new mass function M(r,ϵ), such that we may formulate new classes of spherically symmetric regular black hole solutions, where the curvature invariants are well-behaved in all spacetime. The main differences between the General Relativity and our results in the Rainbow gravity are: a) The intensity of the electric field is inversely proportional to the energy scale. The higher the energy scale, the lower the electric field intensity; b) the region where the strong energy condition (SEC) is violated decreases as the energy scale increases.

Rainbow spacetime from a nonlocal gravitational uncertainty principle

The occurrence of spacetime singularities is one of the peculiar features of Einstein gravity, signalling limitation on probing short distances in spacetime. This alludes to the existence of a fundamental length scale in nature. On the contrary, the Heisenberg quantum uncertainty relation seems to allow for probing arbitrarily small length scales. To reconcile these two conflicting ideas in line with a well-known framework of quantum gravity, several modifications of Heisenberg algebra have been proposed. However, it has been extensively argued that such a minimum length would introduce nonlocality in theories of quantum gravity. In this letter, we analyze a previously proposed deformation of the Heisenberg algebra (i.e., ) for a particle confined in a box subjected to a gravitational field. For the problem in hand, such deformation seems to yield an energy-dependent behavior of spacetime in a way consistent with gravity's rainbow, hence demonstrating a connection between non-locality and gravity's rainbow.

Aharonov–Bohm effect for bound states in the cosmic string spacetime in the context of rainbow gravity

We explore a scenario of the general relativity determined by the framework of the rainbow gravity with the purpose of searching for analogues of the Aharonov-Bohm effect. By focusing on the confinement of the Dirac field and the scalar field to a hard-wall confining potential in a modified background of the cosmic string spacetime, we examine the effects of the rainbow gravity and the topology of the cosmic string spacetime. Then, we compare each spectrum of energy with the cases where the rainbow gravity is absent.

A non-static quantum inspired spacetime in f(R) gravity: Gravity's rainbow

In this note we explore a non-static spacetime in quantum regime in the background of f(R) gravity. The time dependent Vaidya metric which represents the spacetime of a radiating body like star is studied in an energy dependent gravity's rainbow, which is a UV completion of General Relativity. In our quest we have used gravitational collapse as the main tool. The focus is to probe the nature of singularity (black hole or naked singularity) formed out of the collapsing procedure. This is achieved via a geodesic study. For our investigation we have considered two different models of f(R) gravity, namely the inflationary Starobinsky's model and the power law model. Our study reveals the fact that naked singularity is as good a possibility as black hole as far as the central singularity is concerned. Via a proper fine tuning of the initial data, we may realize both black hole or naked singularity as the end state of the collapse. Thus this study is extremely important and relevant in the light of the Cosmic Censorship hypothesis. The most important result derived from the study is that gravity's rainbow increases the tendency of formation of naked singularities. We have also deduced the conditions under which the singularity will be a strong or weak curvature singularity. Finally in our quest to know more about the model we have performed a thermodynamical study. Throughout the study we have obtained results which involve deviation from the classical set-up. Such deviations are expected in a quantum evolution and can be attributed to the quantum fluctuations that our model suffers from. It is expected that this study will enhance our knowledge about quantization of gravity and subsequently about the illusive theory of quantum gravity.

Effects of Planck-scale-modified dispersion relations on the thermodynamics of charged black holes

Considering corrections produced by modified dispersion relations on the equation of state parameter of radiation, we study the induced black hole metric inspired by Kiselev's ansatz, thus defining a deformed Reissner-Nordstr\"{o}m metric. In particular, we consider thermodynamic properties of such a black hole from the combined viewpoints of the modified equation of state parameter and the phenomenological approach to the quantum gravity problem called rainbow gravity.

Gravastar: An alternative to black hole

In this work, we review thoroughly the origin, development and present status of gravastar which has been thought to be an alternative to black hole along with its future feasibility in the sense of astrophysical observation. The Mazur–Mottola model of the gravastar is introduced first followed by a review of its generalizations within the context of general relativity including physical applications like primordial and cylindrical gravastars. The study of gravastar in higher- and lower-dimensional general relativity (GR) including the higher-dimensional theories with physical insight like the Randall–Sundrum model is presented. The gravastar models in a number of modified gravity models starting from [Formula: see text] to Rastall–Rainbow gravity have been reviewed.

Rainbow gravity corrections to the information flux of a black hole and the sparsity of Hawking radiation

In this paper, we investigated the information flux of Schwarzschild black hole and the sparsity of Hawking radiation in the presence of rainbow gravity. The results demonstrate that the rainbow gravity has a very significant effect on the information flux. When the mass of rainbow black hole approaches to the order of Planck scale, the Bekenstein entropy loss per emitted quanta in terms of the mass of black hole reduces to zero. Furthermore, we also find the sparsity of Hawking radiation in rainbow gravity is no longer a constant; instead, it monotonically decreases as the mass of black hole decrease. At the final stages of evaporation, contrary to those of GUP case, the modified sparsity becomes infinity, which indicates the effect of quantum gravity stops Hawking radiation and leads to remnant.

Clash of the Modern/Postmodern Titans? James Joyce in Gravity’s Rainbow

ABSTRACT This paper examines one explicit and many potential references to James Joyce in Thomas Pynchon's Gravity's Rainbow, and explores evidence that a minor Pynchon character may be read as an amalgamated representation of Joyce and his fictions. First, comparisons and contrasts between Joyce and Pynchon are surveyed. The treatment of archetype (which Pynchon associates with Joyce) in Gravity's Rainbow is then explored, finding that Pynchon consistently interrogates, warps, and rejects the concept of archetype. Evidence that Sir Stephen Dodson-Truck in Gravity's Rainbow somehow portrays Joyce is interpreted in comparison with the portrayal of writers in fiction, anxiety of influence, “patricide” and influence, and the portrayal of Joyce in Flann O'Brien's The Dalkey Archive. As tantalizing as a “clash of the titans” between Joyce and Pynchon would be, what emerges is more subtle: aesthetic opposition by Pynchon to archetypes in fiction, coupled with hints of a critique of Joyce's etymological “blithering”.

Nonlinearly charged AdS black hole solutions in three-dimensional massive gravity's rainbow

Two new families of nonlinearly charged and asymptotically anti-de Sitter (AdS) rainbow black holes have been introduced, as the exact solutions to the coupled electromagnetic and gravitational field equations, in massive gravity theory and in the presence of power-law nonlinear electrodynamics. The conserved and thermodynamic quantities such as black hole mass, charge, temperature, entropy and electric potential have been calculated from geometric and thermodynamic approaches. Despite the fact that some of them receive corrections from rainbow functions and nonlinear electrodynamics, it has been proved that they fulfill the first law of black hole thermodynamics. Thermal stability of the black holes has been studied by use of the canonical ensemble and geometrical thermodynamics methods, separately. Regarding the black hole heat capacity and thermodynamic Ricci scalars, the points of type-one and type-two phase transitions and the conditions under which the black holes remain locally stable have been determined. Also, global stability of the novel rainbow black holes has been investigated from the viewpoint of the grand canonical ensemble. Through calculation of Gibbs free energy of the black holes, the points of Hawking-Page phase transition and the size of the black holes which are globally stable or in the radiative phase have been determined.

Photon velocity, power spectrum in Unruh effect with modified dispersion relation

In this paper we propose a new form of generalized uncertainty principle which involves both a linear and a quadratic term in the momentum. From this we have obtained the corresponding modified dispersion relation which is compared with the corresponding relation in rainbow gravity. The new form of the generalized uncertainty principle reduces to the known forms in appropriate limits. We then calculate the modified velocity of photons and we find that it is energy-dependent, allowing therefore for a superluminal propagation. We then derive the ()-dimensional Klein-Gordon equation taking into account the effects of the modified dispersion relation. The positive frequency mode solution of this equation is then used to calculate the power spectrum arising due to the Unruh effect. The result shows that the power spectrum depends on the energy of the particle owing its origin to the presence of the generalized uncertainty principle. Our results capture the effects of both the simplest form as well as the linear form of the generalized uncertainty principle and also points out an error in the result of the power spectrum up to first order in the generalized uncertainty principle parameter existing in the literature.