Triple points and phase transitions of D-dimensional dyonic Ad S black holes with quasitopological electromagnetism in Einstein–Gauss–Bonnet gravity

By considering the negative cosmological constant Λ as a thermodynamic pressure, we study the thermodynamics and phase transitions of the D-dimensional dyonic Ad S black holes(BHs) with quasitopological electromagnetism in Einstein–Gauss–Bonnet(EGB) gravity. The results indicate that the small/large BH phase transition that is similar to the van der Waals(vdW) liquid/gas phase transition always exists for any spacetime dimensions. Interestingly, we then find that this BH system exhibits a more complex phase structure in 6-dimensional case that is missed in other dimensions.Specifically, it shows for D = 6 that we observed the small/intermediate/large BH phase transitions in a specific parameter region with the triple point naturally appeared. Moreover, when the magnetic charge turned off, we still observed the small/intermediate/large BH phase transitions and triple point only in 6-dimensional spacetime, which is consistent with the previous results. However, for the dyonic Ad S BHs with quasitopological electromagnetism in Einstein–Born–Infeld(EBI) gravity, the novel phase structure composed of two separate coexistence curves observed by Li et al. [Phys. Rev. D105 104048(2022)] disappeared in EGB gravity. This implies that this novel phase structure is closely related to gravity theories, and seems to have nothing to do with the effect of quasitopological electromagnetism. In addition, it is also true that the critical exponents calculated near the critical points possess identical values as mean field theory. Finally, we conclude that these findings shall provide some deep insights into the intriguing thermodynamic properties of the dyonic Ad S BHs with quasitopological electromagnetism in EGB gravity.

Generalized Newton’s Theory of Universal Gravitation and Black Holes

The Newton’s theory of universal gravitation is generalized. Significantly strong at short distances central interaction of bodies and particles is established in comparison with Newtonian. A connection is found with Black Holes, with the horizon of events. Possibility of systematization of all Black Holes is shown. An illustration is given on the example of Black Hole SgrA*.

Quantum Unruh Effect on Radiation of Black Holes

The quantum Unruh effect on radiation of a gravitational object including a black hole is analyzed and calculated. It is surprisingly found that the well-known Hawking radiation of a black hole is not physical. Applying the Stephan-Boltzmann law with the use of the Unruh radiation temperature at the surface of a black hole to calculate the power of radiation of the black hole is conceptually unphysical. This is because the Unruh radiation temperature results from the gravitational field of the object rather than from the thermal motion of matter of the object, so that the Stephan-Boltzmann law is not applicable. This paper shows that the emission power of Unruh radiation from a gravitational object should be calculated in terms of the rate of increase of the total Unruh radiation energy outside the object. The result obtained from this study indicates that a gravitational object can emit Unruh radiation when the variation of its mass and radius satisfies an inequality of dM/M > 1.25dR/R. For a black hole, the emission of Unruh radiation does not occur unless it can loose its mass (dM < 0). The emission power of Unruh radiation is only an extremely tiny part of the rate of mass-energy loss if the black hole is not extremely micro-sized. This study turns down our traditional understanding of the Hawking radiation and thermodynamics of black holes.

How Dark Energy Might Be Produced by Black Holes

If confirmed, the new galactic observations in support of rapidly growing supermassive black holes in association with their production of dark energy may provide for a quantum leap forward in our understanding of black holes, dark energy, and universal expansion. The primary implication of these observations is that growth of black holes may well be coupled with universal expansion (“cosmological coupling”). Study of the Flat Space Cosmology (FSC) model, in conjunction with these new observations, suggests a novel mechanism of “black hole dark energy radiation”. This brief note gives a rationale for how the high gravitational energy density vacuum within or adjacent to a black hole horizon could be sufficiently energetic to pull entangled pairs of positive matter energy particles and negative dark energy “particles” of equal magnitude out of the horizon vacuum and send them off in opposite directions (i.e., gravitationally-attractive matter inward and gravitationally-repelling dark energy outward). One effect would be that a black hole can rapidly grow in mass-energy without mergers or the usual accretion of pre-existing matter. A second effect would be continual production of dark energy within the cosmic vacuum, fueling a continuous and finely-tuned light-speed expansion of the universe.

Black Holes and the Third Law of Thermodynamics Revisited

Black holes contradict the Nernst-Planck (N/P) version of the 3rd law of thermodynamics, but agree with its unattainability (U) version. This happens without contradiction, because the N/P and U versions are not equivalent, namely, N/P implies U but U does not imply N/P. So, black holes obey the weaker version of the 3rd law, but not the stronger one.

A New Proposal for Black Holes

The understanding of what a black hole is like is not easy and may not yet be well understood. The introduction of canonical quantization into the issue has not been significant to our understanding. However, introducing affine quantization, a new procedure, offers a very unusual expression that seems to be plausible, and quite profound as well.

Adiabaticity Violated Not Enough: Presume Primordial Black Holes to Generate Gravitons for Cosmological Constant, as Candidate for DE Initially

Instant preheating as given in terms of window where adiabaticity is violated is a completely inefficient form of particle production if we use Padmandabhan scalar potentials. This necessitates using a very different mechanism for early universe gravition production as an example which is to break up the initial “mass” formed about 1060 times Planck mass into graviton emitting 105 gram sized micro black holes. The mechanism is to assume that we have a different condition than the usual adiabaticity idea which is connected with reheating of the universe. Hence, we will be looking at an earlier primordial black hole generation for generation of gravitons.

Trials to Resolve Black Holes Instabilities in Brane World Cosmology Models

In this letter, we report on our trials to remove the instability of black holes in brane world cosmological models consisting of two branes and a bulk. In order to resolve this problem, general types of interaction potentials were employed. Careful analyses have shown that although the black holes instabilities were removed, a sort of arbitrariness adherent to the motion of the two branes towards each other has taken place leading to an unstable system. Thus, the models seem to us rather paradoxical.

Spherical and Circular Non-Equatorial Photon Orbits around Kerr Black Holes

By analytically solving the equation of azimuthal null geodesics for spherical photon trajectories, a parametric representation of the corresponding segment of the orbit is obtained. The solution parameter is the latitude coordinate. The dependences of the orbital radius on the black hole spinning parameter and the angle of inclination of its plane with respect to the rotation axis are calculated for flat circular non-equatorial orbits. It is proved that all spherical photon trajectories in the Kerr spacetime are unstable, as well as equatorial ones, and the critical photon orbits in the Schwarzschild metric.

From Black Holes to Information Erasure: Uniting Bekenstein’s Bound and Landauer’s Principle

This research aims to integrate Bekenstein’s bound and Landauer’s principle, providing a unified framework to understand the limits of information and energy in physical systems. By combining these principles, we explore the implications for black hole thermodynamics, astrophysics, astronomy, information theory, and the search for new laws of nature. The result includes an estimation of the number of bits stored in a black hole (less than 1.4 × 1030 bits/m3), enhancing our understanding of information storage in extreme gravitational environments. This integration offers valuable insights into the fundamental nature of information and energy, impacting scientific advancements in multiple disciplines.

Quantum Unruh Effect on Singularities of Black Holes

It is generally believed that matter inside or once entering a black hole will gravitationally fall into the center and form a size-less singularity, where the density goes to infinity and the spacetime breaks down with infinite curvature or gravitation. In accordance to the Unruh effect, one of the most surprizing predictions of quantum field theory, however, it is found from this study that such singularity cannot be actually formed because it violates the law of energy conservation. The total Unruh radiation energy of the size-less singularity is shown to be infinite, much greater than that the collapsing matter can generate. All the energies of the collapsing matter including the gravitational potential energy, deducted, are far below the Unruh radiation energy, increased, for the collapsing matter to form the singularity. The collapsing matter actually formed is shown to be not a size-less singular point but a small sphere with a finite radius, which is found to be dependent of the mass of the singularity sphere, approximately proportional to the square root of the mass. The radius of the singularity sphere cannot be zero, unless the mass also approaches to zero. The result obtained from this study not only provides us a quantum solution to the problem of black hole singularity, but also leads to profound implications to the spacetime and cosmology. The Unruh effect excludes a black hole to form a size-less singularity, which has a finite mass but infinite density, curvature, and Unruh radiation energy. A point-like or size-less singularity can only be massless and naked.

Theory to the Mystery of the Super Massive Black Holes

Vera Rubin measured the rotational speeds of galaxies, Ref. [1] 1983, and she found that the masses of galaxies were not enough to produce the measured speeds of rotation. Therefore, it was inferred that there must be an unknown matter which is many times the known visible and dark matter. In this study, the solution to the dark matter mystery of spiral galaxies is a four-dimensional mass in the space of four distance dimensions, coordinates: x,y,z,x', in which x' is the fourth distance dimension. The four-dimensional mass is a black hole, and it generates the main gravitation field of the galaxy. This mysterious black hole is located in the fourth dimension at the distance x' = X'. The rotational speed distribution curves of the galaxy NGC 3198 have been presented in Ref. [2]. The speed distribution curve of the galactic halo in that publication corresponds to the speed distribution curve of the four-dimensional black hole in this study. In order to find out how well this four-dimensional model functions, the speed distribution curve of the four-dimensional black hole was calculated, and it was compared with the halo curve of Ref. [2]. The conclusion was that the calculated speed distribution curve of the black hole was a good match to the halo curve of Ref. [2]. Furthermore, the rotational speed distribution curves of the four-dimensional black hole were calculated by using different values of the reduced distance X', which yielded at the distance X' = 0 a black hole of radius R = 7.7 × 1017 m. By using the relativistic Lorentz transformation, it was shown in this study that a star falling into the four-dimensional black hole remains rotating it at near speed of light, and cannot fall into the actual black hole.

Does QM Embedded in 5th Dimensional Embedding Allow for Classical Black Hole Ideas Only in Early Universe, Whereas Corda Special Relativity Plus QM May Eliminate Event Horizons for Black Holes after Big Bang?

We first look at the possibility that the ideas of event horizons for black holes may have their application only in early universe conditions whereas Corda’s ground breaking work rejecting event horizons may be due to the formation of quantum mechanics free of an embedding in 5 dimensions allowing for a simpler more direct approach, which rejects the idea of a firewall. First, we present the idea of classical black hole physics applied only once as for the early universe, whereas in such a setting, there may be a way to present NLED and structure formation due to an initial entropy approach as outlined. Then the ideas of Corda’s breakthrough are presented for the reasons he illuminated in his recent work, due to QM being fully formed separate from higher dimensional embedding after the initial evolution of the universe.

On Thermodynamical Relation Between Rotating Charged BTZ Black Holes and Effective String Theory

In this paper we study the first law of thermodynamics for the （2＋1）-dimensional rotating charged BTZ black hole considering a pair of thermodynamical systems constructed with the two horizons of this solution. We show that these two systems are similar to the right and left movers of string theory and that the temperature associated with the black hole is the harmonic mean of the temperatures associated with these two systems.

Quantum Gravity, Constant Negative Curvatures, and Black Holes

For purposes of quantization, classical gravity is normally expressed by canonical variables, namely the metric and the momentum . Canonical quantization requires a proper promotion of these classical variables to quantum operators, which, according to Dirac, the favored operators should be those arising from classical variables that formed Cartesian coordinates;sadly, in this case, that is not possible. However, an affine quantization features promoting the metric and the momentric to operators. Instead of these classical variables belonging to a constant zero curvature space (i.e., instead of a flat space), they belong to a space of constant negative curvatures. This feature may even have its appearance in black holes, which could strongly point toward an affine quantization approach to quantize gravity.

The Origin of Cosmic Structures Part 3 — Supermassive Black Holes and Galaxy Cluster Evolution

In Part 1 of this work, we showed that our new model of cosmology can account for the origin of all cosmic structures ranging in size from stars up to superclusters. In this model, at the time of nucleosynthesis, an imprint embedded in the vacuum regulated the creation of the protons (and electrons) that later made up the structures. Immediately after nucleosynthesis and for a considerable period afterward, the evolution was completely determined by the expansion of the universe. Gradually, however, gravitational influences became more important until finally, the expansion of the structures-to-be ceased at their zero velocity points. Stars, galaxies, and galaxy clusters all reached their zero velocity points more or less simultaneously at the usually accepted time of the beginning of galaxy formation. From that point onward, the evolution gravitation came to dominate the evolution although the expansion still exerted its influence. In this paper, we examine the subsequent cluster evolution in some detail. We establish the conditions required to prevent a free-fall collapse of the clusters and then show that galaxies with quasar-like active nuclei located within the cluster were the sources of the necessary radiation. We also show that the required galactic supermassive black holes were a consequence of the initial free-fall collapse of all galaxies.

Penrose Suggestion as to Pre Planck Era-Black Holes Showing Up in Present Universe Data Sets Discussed, with a Possible Candidate as to GW Radiation Which May Provide Initial CMBR Data

What we are doing is three-fold. First, we examine the gist of the Penrose suggestion as to signals from a prior universe showing up in the CMBR. i.e. , this shows up as data in the CMBR. Second, we give a suggestion as to how super massive black holes could be broken up s of a prior Universe cycle by pre big bang conditions, with say millions of pre-Planck black holes coming up out of a breakup of prior universe black holes. Three, we utilize a discussion as to Bose Einstein Condensates set as Gravitons as to composing the early universe black holes. The BEC formulation gives a number N of gravitons, linked to entropy, per black hole, which could lead to contributions to the alleged CMBR perturbations, which were identified by Penrose et al.

Abbott-Deser-Tekin Charge of Dilaton Black Holes with Squashed Horizons

We consider the conserved charge of static black holes with squashed horizons in the Einstein-Maxwell-dilaton theory via both the Abbott-Deser-Tekin （ADT） method and its off-shell generalization. We first make use of the original ADT method to compute the mass of the dilaton squashed black holes in terms of three different reference spacetimes, which are the asymptotic geometry, the flat background and the spacetime of the Kaluza- Klein monopole with boundary matched to the original metric, respectively. Each mass satisfies the first law of black hole thermodynamics, although the mass computed on the basis of the boundary matching the Kaluza- Klein monopole is different from that of the other two reference spacetimes. Then the mass of the black holes is evaluated through the off-shell generalized ADT method.

Variations of broad emission lines from periodicity QSOs under the interpretation of supermassive binary black holes with misaligned circumbinary broad line regions

Quasars with periodic light curves are considered as candidates of supermassive binary black hole(BBH)systems.One way for further confirmations may be searching for other characteristic signatures,such as those in their broad emission lines(BELs),if any,which require a thorough understanding on the response of BELs to the BBH systems.In Ji et al.(2021),we have investigated the response of circumbinary broad line region(BLR)to the central active secondary black hole under the relativistic Doppler boosting(BBH-DB)and intrinsic variation(BBH-IntDB)dominant mechanisms for continuum variation by assuming the middle plane of the BLR aligned with the BBH orbital plane.In this paper,we explore how the BEL profiles vary when the BLR is misaligned from the BBH orbital plane with different offset angles under both the BBH-DB and BBH-IntDB scenarios.Given a fixed inclination angle of the BBH orbital plane viewed in edge-on and similar continuum light curves produced by the two scenarios,increasing offset angles make the initial opening angle of the circumbinary BLR enlarged due to orbital precession caused by the BBH system,especially for clouds in the inner region,which result in Lorentzlike BEL profiles for the BBH-DB model but still Gaussion-like profiles for the BBH-IntDB model at the vertical BLR case.The amplitude of profile variations decreases with increasing offset angles for the BBHDB scenario,while keeps nearly constant for the BBH-IntDB scenario,since the Doppler boosting effect is motion direction preferred but the intrinsic variation is radiated isotropically.If the circumbinary BLR is composed of a coplanar and a vertical components with their number of clouds following the mass ratio of the BBHs,then the bi-BLR features are more significant for the BBH-IntDB model that requires larger mass ratio to generate similar continuum variation than the BBH-DB model.

Eliminating Black Holes Singularity in Brane World Cosmology

In recent works, a construction was proposed resulting in emergent universes inside black holes. This result can be obtained from a 4D black hole embedded in a 5D spacetime with the fifth dimension compactified on a circle [0, 2] (0 and 2 are identified) such that the two branes are at 0 and 1. In the present work, we study this setup by deriving particles’ equations of motion in the new universes, based on redefining energy and angular momentum. This leads to disappearance of the singularity in centers of black holes in classical General Relativity.