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Einstein–Newcomb–de Sitter (ENdS) space is de Sitter’s modification of spherical space used by Einstein in his first cosmological model paper published in 1917. The modification by de Sitter incorporated the topological identification of antipodal points in space previously proposed by Newcomb in 1877. De Sitter showed that space topologically modified in this way (called elliptical or projective space) satisfies Einstein’s field equations. De Sitter also found that in a space with constant positive curvature, spectral lines of remote galaxies would be red-shifted (called the de Sitter effect). However, de Sitter’s formulae relating distances to red shifts do not satisfy observational data. The likely reason for this mismatch is that de Sitter mainly focused on space curvature and ignored the identification of antipodal points. Herein, we demonstrate that it is this particular feature that allows an almost perfect fit of the ENdS-based cosmological model to observational data. We use 1701 sources from the type Ia supernovae data sample called Pantheon+, which was previously used to fit the ΛCDM model. ΛCDM and ENdS diverge in their predictions for red shifts exceeding z∼2.3. Since there are no available type Ia supernovae (SNe) data for higher red shifts, both models can be validated by using an additional sample of 193 gamma-ray bursts (GRBs) spanning red shifts up to z∼8. This validation shows that the minimum χ2 for the SNe+GRBs sample is about 2.7% smaller for the ENdS space model than for the ΛCDM model.

Dissolution of carbonate rocks is a complex process in which the interplay of flow, transport, reaction, and geometric evolution plays an important role. The nonlinear couplings between these processes may lead to the formation of intricate patterns, including spontaneously formed channels (wormholes) [1]. It has been long established that the shapes of the dissolution patterns depend on fluid flow and mineral dissolution rates [2]. Recently, it also has become increasingly clear that pore-scale processes can impact large-scale morphologies [3,4]. However, the effects of pore-scale mixing on large-scale patterns remain unclear.In this work, we investigate the effect of pore-scale mixing processes on the evolution of dissolution channels. Pore space is represented by a network of cylindrical tubes with the diameter of each segment increasing in proportion to the local reactant consumption. The inlet concentration of each pore is controlled by local mixing rules. Two different mixing protocols are considered: full mixing, in which the incoming reactant fluxes are assumed to be completely mixed at the intersection, and streamline routing, where the tracer follows the streamlines into the outgoing pores. We found that streamline routing enhances the flow focusing particularly strongly in moderate Damköhler number regimes where relatively wide dissolution channels appear spontaneously in the system. With the same initial conditions as the full mixing case, the winning channels obtained with streamline routing not only propagate faster but also could grow at a different location in the system. The enhanced flow focusing caused by streamline routing produces thinner wormholes and leads to shorter breakthrough times. Lastly, the evolution of velocity distribution is also found to be distinctive depending on the mixing rule.[1] Hoefner, M. L. and Fogler, H. S. AIChE J. 34: 45–54, 1988[2] Golfier, F., et al. J. Fluid. Mech. 457: 213-254, 2002[3] Li, L., Peters, C. A., & Celia, M. A. Adv. Water Res., 29: 1351–1370, 2006[4] R. Roded, P. Szymczak, R. Holtzman, Geophys. Res. Lett. 48:e2021GL093659, 202

Eski Uygurcada önemli bir yere sahip olan Tantrik Budizm büyü, cinsellik, yoga gibi ezoterik bir yapıya sahiptir ve çeşitli ritüelleri içerir. Bu ritüeller kişinin yeniden doğuşunu engellerken ritüellerin asıl amacı kişiyi arındırmak ve ilahi bedene ulaşmasını sağlamaktır. Bunun için bedendeki delikler olan dokuz kapıyı/deliği temizlemek gerekir. Bu dokuz delik düşüncesi Bhagavadgītā’da sürdürülür ve dokuz delik iki göz, iki kulak, iki burun deliği, ağız ve erkekteki iki boşaltım organı (idrar sistemi ve anüs) olarak sıralanır. Ayrıca Kaṭha Upaniṣad metinlerinde bu dokuz deliğe ek olarak göbek ve kafatasının üst kısmındaki açıklıktan bahsedilir ve böylece on bir kapılı şehirden bahsedilir. Bir insanın yeniden doğması için, cehennem, hayvan, insan, tanrı hayat şekillerinden birinde, seçtiği deliklere göre doğması gerekir. Bu, bir âlemden diğerine geçişi gösterir ki bu da günümüzde astrofizik alanında tartışılan kara delikler, solucan delikleri ve paralel evrenleri akla getirir. Bütün bunlara ek olarak, insanın mikro kozmoloji olarak kabul edilmesinden dolayı, bedendeki delikler makro kozmoloji ile özdeşleştirilebilir. Bu çalışma, insan vücudundaki delikleri ve bu deliklerin gezegenlerle olan bağlantılarını inceleyecek ve bu delikler kara delikler, solucan delikleri ve paralel evrenler fikriyle ilişkilendirerek analiz edecektir., Tantric Buddhism, which is one of the important fields of study of the Old Uyghur, has an esoteric structure such as magic, sexuality, and yoga and includes various rituals. While these rituals prevent the rebirth of the person, the main goal of the rituals is to purify the person and to allow him/her to reach the divine body. For this, it is necessary to clean the nine doors/orifices called orifices that exist in the body. This tradition of nine orifices is continued in the Bhagavadgītā, and the nine cavities are listed as two eyes, two ears, two nostrils, the mouth, and the two excretory organs in the male (urinary system and anus). Besides, in Kaṭha Upaniṣad texts, in addition to these nine orifices, the opening at the navel and top of the skull and the city with eleven gates are referred to. If a person is to be reborn, s/he has to be born in one of the life forms such as hell, animal, human, or god, according to the orifices s/he as chosen. This indicates the transition from one realm to another, which brings to mind black holes, wormholes, and parallel universes discussed today in the field of astrophysics. In addition to all these, due to the acceptance of humans as micro cosmologists, his/her orifices are identified with macro cosmology. This study will investigate the orifices in the human body and their connections with the planets, as well as analyze these spaces in relation with the idea of black holes, wormholes, and parallel universes.

In this thesis, the methods of differential topology are used to study the gravitational lensing effect. First, the reader is taken on a brief tour through the basics of black holes, wormholes, gravitational lensing and the mathematical tools of Fermat's principle, Morse theory and the Gauss-Bonnet theorem. Then, the understanding is deepened by applying Morse theory and the Gauss-Bonnet theorem to gravitational lensing. In the first part, we have fixed an observation event p and the worldline of a light source gamma and identified the set of all past-oriented lightlike geodesics from p to gamma. Since each such geodesic corresponds to an image of the light source on the observer’s sky, this allows us to examine the lensing properties of wormholes. As key results, we have proven with the help of Morse theory that under very mild conditions on gamma, the observer is able to see infinitely many images of gamma. Moreover, we have studied some qualitative features of the lightlike geodesics with the help of two potentials that determine the sum of the centrifugal and Coriolis forces of observers in circular motion for the case that the observers’ velocity approaches the velocity of light. We have exemplified the general results with two specific wormhole spacetimes. In the second part, we have shown with the help of Fermat’s principle that every lightlike geodesic in the Brill metric projects onto a geodesic of a two-dimensional Riemannian metric, the so-called optical metric. The optical metric is defined on a (coordinate) cone, whose opening angle is determined by the impact parameter of the lightlike geodesic. We have shown that the optical metrics on cones with different opening angles are locally isometric. With the help of the Gauss-Bonnet theorem, we have demonstrated that the deflection angle of a lightlike geodesic is determined by an area integral over the Gaussian curvature of the optical metric. Last but not least, we have investigated gravitational lensing of Brill wormholes by examining the existence of photon circles and propagation possibilities of light rays.

The article explores the possibility of using CHOPS technology in the Karazhanbas heavy oil field, where there is a frequent occurrence of high-viscosity, resinous and sandy oil plugs. When using this method, relatively high oil recovery coefficients can be achieved due to the destruction of the reservoir and the formation of macroscopic wormholes, which leads to an increase in reservoir permeability. Аннотация В статье исследуется возможность использования технологии CHOPS на месторождении тяжелой нефти Каражанбас, где наблюдается частое проявление нефтяных высоковязких, смолистых и песчаных пробок. При использовании этого метода могут быть достигнуты относительно высокие коэффициенты нефтеотдачи за счет разрушения коллектора и образования макроскопических каналов (wormholes), что приводит к увеличению проницаемости пласта., {"references":["1.\tКалешева Гульмира Ермухамбетовна. Развитие технологий добычи высоковязкой нефти в месторождении Каражанбас. Молодой учёный 9 (89), 2015. cтр. 446-450.","2.\tPatrick M. Collins, Maurice B. Dusseault, Darcy Dorscher, Ed Kueber. Implementing CHOPS in the Karazhanbas heavy oil field, Kazakhstan. World heavy oil congress 500. 2008. 1-17 p.","3.\tB. Tremblay. Cold Flow: A Multi-Well Cold Production (CHOPS) Model, Canada. Journal of Canadian Petroleum Technology. 2007. 22-28 p.","4.\tG. Han, M. Bruno, M.B. Dusseault. How Much Oil You Can Get From CHOPS, Canada. Journal of Canadian Petroleum Technology. 2005. 24-32 p.","5.\tАзиз Абишев, Виталий Токарев, Марат Сагындыков. Анализ применения методов нефтеотдачи на месторождении Каражанбас. Journal of petroleum Technology(SPE) 192553, 2018. стр.1-11.","6.\tZhanbolat Armanovich Esetov, Muradin Fayziyevich Turdiyev, Alim Feyzrakhmanovich Kemalov, Ilmira Maratovna Abdrafikova. Thermal- Steam Cyclic Processing Technology of Development Objects In Karazhanbas Kazakhstan Field. Indian Journals of Science and Technology (9(18)), 2016. 1-9 p.","7.\tMaurice B. Dusseault, Baoci Xu. CHOPS in Jilin Province China. Journal of petroleum Technology(SPE) 79032, 2002. 1-7 p.","8.\tKhosrow Naderi, Nikolas Romaniuk, Baki Ozum. Improvement Of the Chops Process Efficiency. Journal of petroleum Technology(SPE) 175390, 2015. 1-13 p.","9.\tA. Rangriz Shokri, T. Babadagli. An Approach Model CHOPS. Journal of petroleum Technology(SPE) 159437, 2012. 1-12 p.","10.\tBrian Vander Heyden, Xia Ma. Multiscale Stimulation of Chops Wormholes. Journal of petroleum Technology(SPE) 163063, 2013. 1-12 p."]}

In a multi-fold universe, gravity emerges from Entanglement through the multi-fold mechanisms. As a result, gravity-like effects appear in between entangled particles, whether they be real or virtual. Long range, massless gravity results from entanglement of massless virtual particles. Entanglement of massive virtual particles leads to massive gravity contributions at very smalls scales. Multi-folds mechanisms also result in a spacetime that is discrete, with a random walk fractal structure, and non-commutative geometry that is Lorentz invariant and where spacetime nodes and particles can be modeled with microscopic black holes. All these recover General Relativity (GR) at large scales, and semi-classical model remain valid till smaller scale than usually expected. Gravity can therefore be added to the Standard Model resulting in what we defined as SMG. This can contribute to resolving several open issues with the Standard Model without new Physics other than gravity. These considerations hint at an even stronger relationship between gravity and the Standard Model. Among the multi-fold SMG discoveries, the apparition of an-always in-flight, and hence non-interacting, right-handed neutrinos, coupled to the Higgs boson is quite notable. It is supposedly always around right-handed neutrinos, due to chirality flips by gravity of the massless Weyl fermions, induced by 7D space time matter models and hidden behind the Higgs boson or field at the entry points and exit points of the multi-folds. Massless Higgs bosons modeled as minimal microscopic black holes mark concretized spacetime location. They can condensate into Dirac Kerr-Newman soliton Qballs to produce massive and charged particles, thereby providing a microscopic explanation for a Higgs driven inflation, the electroweak symmetry breaking, the Higgs mechanism, the mass acquisition and the chirality of fermions and spacetime; all resulting from the multi-fold gravity electroweak symmetry breaking. The multi-fold theory has also concrete implications on New Physics like supersymmetry, superstrings, M-theory and Loop Quantum Gravity (LQG). In recent papers, we encountered multi-folds in universes described by non-multi-fold physics, including when discussing how to fix challenges in the quantization of the Hilbert Einstein action by LQG, or in enforcing an equivalence across Quantum Reference Frames for coherent or entangled systems. In this paper, starting from a paper that seeks to encounters EPR = ER beyond (asymptotic) AdS universes, we encounter the presence of multi-folds in GR field equations at Planck scales, in the form of traversable wormholes. Doing so, we also encounter hints that, at such scales, spacetime is discrete, 2D, non-commutative while Lorentz symmetric, and yet to become continuous. Doing so we even explained how the previous sentence is not self-contradictory. These results are in perfect alignment with the results obtained in the multi-fold theory, and, in particular, the multi-fold spacetime reconstruction, including the ultimate Unification (UU), the multi-fold inflation and the multi-fold gravity electroweak symmetry breaking. Then, we derive that spacetime entanglement implies non-commutative spacetime and we clarify the meaning of the ER = EPR and QR = QM conjectures, as facets of the multi-fold theory, that is the umbrella theory that neither GR nor QM can fully model. These conjectures become factual, when seen as such facets. The paper also proposes a re-derivation of the whole multi-fold theory from GR at Planck scales: the top-down-up-and-upper derivation of the multi-fold theory, that rigorously confirms the spacetime reconstruction, and that multi-fold mechanism recover GR. Finally, we provide a new derivation, without any multi-fold assumptions, that gravity is asymptotically safe. The main outcome of the paper remains: universe modeled by GR are multi-fold, and the E/G conjecture is not a conjecture but factual. All these results are strong hints that our real universe may be multi-fold., With some errata applied vs. version 1 => version 1.1 Related papers and discussions at https://shmaesphysics.wordpress.com/shmaes-physics-site-navigation/ and https://shmaesphysics.wordpress.com/2022/02/22/deriving-the-multi-fold-theory-from-general-relativity-at-planck-scale/

If Euclidean wormholes contribute meaningfully to the path integral of quantum gravity they can have important implications for particle physics and cosmology. The dominant effects arise from wormholes whose sizes are comparable to the cut-off scale of effective field theory, for which ultraviolet corrections become relevant. We study corrections to classical axion wormhole solutions in string motivated scenarios in which the dilaton partner of the axion becomes massive. We find corrections near the neck region which are consistent with a recent version of the weak gravity conjecture for axions., Comment: 18 pages, 4 figures, published version

Casimir energy is always suggested as a possible source to create a traversable wormhole. It is also used to demonstrate the existence of negative energy, which can be created in a lab. To generalize this idea, Yukawa modification of a Casimir source has been considered in Remo Garattini (Eur. Phys. J. C 81 no.9, 824, 2021). In this work, we explore the Yukawa–Casimir wormholes in symmetric teleparallel gravity. We have taken four different forms of f(Q) to obtain wormhole solutions powered by the original Casimir energy source and Yukawa modification of the Casimir energy source. In power law form f(Q)=αQ2+β and quadratic form f(Q)=αQ2+βQ+γ, where α,β,γ are constants and Q is non-metricity scalar, we analyze that wormhole throat is filled with non-exotic matter. We find self-sustained traversable wormholes in the Casimir source where null energy conditions are violated in all specific forms of f(Q), while after Yukawa modification, it is observed that violation of null energy conditions is restricted to some regions in the vicinity of the throat.

This paper provides a synopsis and review of the multi-fold theory in preparation for more detailed reviews lectures and books. In a multi-fold universe, gravity emerges from Entanglement through the multi-fold mechanisms. As a result, gravity-like effects appear in between entangled particles that they be real or virtual. Long range, massless gravity results from entanglement of massless virtual particles. Entanglement of massive virtual particles leads to massive gravity contributions at very smalls scales. Multi-folds mechanisms also result into a spacetime that is discrete, with a random walk fractal structure and non-commutative geometry that is Lorentz invariant and where spacetime nodes and particles can be modeled with microscopic black holes. All these recover General Relativity (GR) at large scales and semi-classical model remain valid till smaller scale than usually expected. Gravity can therefore be added to the Standard Model resulting into what we defined as SMG. This can contribute to resolving several open issues with the Standard Model without new Physics other than gravity. These considerations hints at an even stronger relationship between gravity and the Standard Model. Among the multi-fold SMG discoveries, the apparition of an-always in-flight, and hence non-interacting, right-handed neutrinos, coupled to the Higgs boson is quite notable. It is supposedly always around right-handed neutrinos, due to chirality flips by gravity of the massless Weyl fermions, induced by 7D space time matter models and hidden behind the Higgs boson or field at the entry points and exit points of the multi-folds. Massless Higgs bosons modeled as minimal microscopic black holes mark concretized spacetime location. They can condensate into Dirac Kerr-Newman soliton Qballs to produce massive and charged particles, thereby providing a microscopic explanation for a Higgs driven inflation, the electroweak symmetry breaking, the Higgs mechanism, the mass acquisition and the chirality of fermions and spacetime; all resulting from the multi-fold gravity electroweak symmetry breaking. The multi-fold theory has also concrete implications on New Physics. We see this paper as a draft to collect comment and feedback as we evolve it towards a fuller publication. It is the End of 2021 version., Stephane H Maes, (2021), "The Multi-fold Theory: A synopsis", viXra:2112.0144v1, https://shmaesphysics.wordpress.com/2021/12/24/the-multi-fold-theory-a-synopsis-so-far-v2-end-of-2021/, December 24, 2021. Note that additional links will always be available at https://shmaesphysics.wordpress.com/2021/05/03/the-multi-fold-theory-a-synopsis-so-far/ to track the latest and interim versions of the synopsis, as they may be published under different tittle or URL/publication numbers. ____ Also published externally as "The Multi-fold Theory: A synopsis so far, V2 – End of 2021" - https://shmaesphysics.wordpress.com/2021/12/24/the-multi-fold-theory-a-synopsis-so-far-v2-end-of-2021/ (V2 of https://shmaesphysics.wordpress.com/2021/05/03/the-multi-fold-theory-a-synopsis-so-far/).

The Goheer-Kleban-Susskind no-go theorem says that the symmetry of de Sitter space is incompatible with finite entropy. The meaning and consequences of the theorem are discussed in the light of recent developments in holography and gravitational path integrals. The relation between the GKS theorem, Boltzmann fluctuations, wormholes, and exponentially suppressed non-perturbative phenomena suggests: the classical symmetry between different static patches is broken; and that eternal de Sitter space -- if it exists at all -- is an ensemble average., 55 pages, 17 figures

In this paper, we study quantum relativistic features of a scalar field around the Rindler-Schwarzschild wormhole. First, we introduce this new class of spacetime, investigating some energy conditions and verifying their violation in a region nearby the wormhole throat, which means that the object has to have an exotic energy in order to prevent its collapse. Then, we study the behavior of the massless scalar field in this spacetime and compute the effective potential by means of tortoise coordinates. We show that such a potential is attractive nearby the wormhole throat and that is traversable via quantum tunneling by massive particles with sufficiently low energies. The solution of the Klein-Gordon equation is obtained subsequently, showing that the energy spectrum of the field is subject to a constraint which induces a decreasing oscillatory behavior. On imposing Dirichlet boundary conditions on a spherical shell nearby the throat we then determine the particle energy levels, and we use this spectrum to calculate the quantum revival of the eigenstates. Finally, we compute the Casimir energy associated with the massless scalar field at zero temperature. We perform this calculation by means of the sum of modes method. The zero-point energy is regularized using the Epstein-Hurwitz zeta-function. We also obtain an analytical expression for the Casimir force acting on the shell., Comment: 14 pages, 6 figures

The Schwarzschild solution to the Einstein field equation leads to a solution that has been interpreted as wormholes. While many researchers have been sceptical about this interpretation, others have been positive about it. We show that wormholes are not mathematically allowed in the spherical metric of a newly-released unified quantum gravity theory known as collision space-time [1] [2] [3]. We, therefore, have reasons to believe that wormholes in general relativity theory are nothing more than a mathematical artefact due to an incomplete theory, but we are naturally open to discussions about this point. The premise that wormholes likely do not exist falls nicely into line with a series of other intuitive predictions from collision space-time where general relativity theory falls short, such as matching the full spectrum of the Planck scale for micro “black holes”. Wormholes Do Not Exist: They Are Mathematical Artifacts from an Incomplete Gravitational Theory

We present the scientific program of the Spectr-M project aimed at the creation and operation of the Millimetron Space Observatory (MSO) planned for launch in the late 2020s. The unique technical capabilities of the observatory will enable broadband observations of astronomical objects from 50 μm to 10 mm wavelengths with a record sensitivity (up to ∼0.1 μJy) in the single-dish mode and with an unprecedented high angular resolution (∼0.1 μas) in the ground-space very long baseline interferometer (SVLBI) regime. The program addresses fundamental priority issues of astrophysics and physics in general that can be solved only with the MSO capabilities: 1) the study of physical processes in the early Universe up to redshifts z ∼ 2 106 through measuring μ-distortions of the cosmic microwave background (CMB) spectrum, and investigation of the structure and evolution of the Universe at redshifts z

Wormholes are hypothetical topologically-non-trivial structures of the spacetime. From the theoretical point of view, the possibility of their existence is challenging but cannot be ruled out. This article is a compact and non-exhaustive review of past and current efforts to search for astrophysical wormholes in the Universe., 13 pages, 9 figures. Invited contribution to the special issue of Universe "Recent Advances in Wormhole Physics" (Eds. K.A. Bronnikov and S. Sushkov). Partially based on e-Print 2010.03947 [gr-qc], e-Print 2007.12184 [gr-qc], e-Print 1910.00429 [gr-qc], e-Print 1810.03432 [hep-th]. v2: added some references

Given the recent development of rotating black-bounce-Kerr spacetimes, for both theoretical and observational purposes it becomes interesting to see whether it might be possible to construct black-bounce variants of the entire Kerr-Newman family. Specifically, herein we shall consider black-bounce-Reissner-Nordstr\"om and black-bounce-Kerr-Newman spacetimes as particularly simple and clean everywhere-regular black hole "mimickers" that deviate from the Kerr-Newman family in a precisely controlled and minimal manner, and smoothly interpolate between regular black holes and traversable wormholes. While observationally the electric charges on astrophysical black holes are likely to be extremely low, $|Q|/m \ll 1$, introducing any non-zero electric charge has a significant theoretical impact. In particular, we verify the existence of a Killing tensor (and associated Carter-like constant) but without the full Killing tower of principal tensor and Killing-Yano tensor, also we discuss how, assuming general relativity, the black-bounce-Kerr-Newman solution requires an interesting, non-trivial matter/energy content., Comment: V1: 27 pages, 0 figures, 61 references. V2: Still 27 pages, 0 figures, no physics changes, 6 references added (now 67 references). V3: Published and final version, now 29 pages, 2 figures added, minor discussion added on page 17, 2 references added (now 69 references)

I give a historical survey of the discussions about the existence of closed timelike curves in general relativistic models of the universe, opening the physical possibility of time travel in the past, as first recognized by K. G\"odel in his rotating universe model of 1949. I emphasize that journeying into the past is intimately linked to spacetime models devoid of timelike singularities. Since such singularities arise as an inevitable consequence of the equations of general relativity given physically reasonable assumptions, time travel in the past becomes possible only when one or another of these assumptions is violated. It is the case with wormhole-type solutions. S. Hawking and other authors have tried to "save" the paradoxical consequences of time travel in the past by advocating physical mechanisms of chronological protection; however, such mechanisms remain presently unknown, even when quantum fluctuations near horizons are taken into account. I close the survey by a brief and pedestrian discussion of Causal Dynamical Triangulations, an approach to quantum gravity in which causality plays a seminal role., Comment: 11 pages

The recent opening of gravitational wave astronomy has shifted the debate about black hole mimickers from a purely theoretical arena to a phenomenological one. In this respect, missing a definitive quantum gravity theory, the possibility to have simple, meta-geometries describing in a compact way alternative phenomenologically viable scenarios is potentially very appealing. A recently proposed metric by Simpson and Visser is exactly an example of such meta-geometry describing, for different values of a single parameter, different non-rotating black hole mimickers. Here, we employ the Newman--Janis procedure to construct a rotating generalisation of such geometry. We obtain a stationary, axially symmetric metric that depends on mass, spin and an additional real parameter $\ell$. According to the value of such parameter, the metric may represent a rotating traversable wormhole, a rotating regular black hole with one or two horizons, or three more limiting cases. By studying the internal and external rich structure of such solutions, we show that the obtained metric describes a family of interesting and simple regular geometries providing viable Kerr black hole mimickers for future phenomenological studies., Comment: 20+ pages, lots of pictures; minor fixes, references added

Our goal in this work was to study some important properties about black holes and wormholes. Among the most important aspects we study we can divide them in two main topics. The first concerns the oscillation modes in systems such as black holes and wormholes. These systems must emit oscillations when they are disturbed by some external field. The amplitudes of these oscillations decrease with time. We typically call these oscillations quasi-normal modes QNMs. The second aspect we investigated, which has been attracting a lot of interest from researchers today, was gravitational lenses. Then we used the semi-analytical WKB method of third order and sixth order to compute the QNMs of some metrics addressed in this work. To compute the light deflection due to the influence of the gravitational lens, we use the Gauss-Bonnet theorem when we consider small deviations of the angles of the trajectories. The first two solutions we treat in this thesis were constructed based on the so-called bumblebee gravity, where the presence of Lorentz violation field contributes to the solution of Einstein equations. The first describes an exact black hole solution of the Schwarzschild type and the second a traversable wormhole, both dependent on a λ violation parameter. In the case of the wormhole solution in bumblebee gravity we determine which energy conditions are preserved to sustain this type of wormhole. We also determined the values that the parameter λ must assume, in order to allow us to calculate the QNMs using the WKB method. For the Schwarzschild solution in bumblebee gravity, it was also possible to determine the QNMs using the WKB method of third and sixth order. With the Gauss-Bonnet theorem we found an expression of the light deviation for small angles this time in Kalb-Ramond gravity. We further investigate two solutions of rotating black holes by calculating expressions of the deflection angle deviations using an extension of the Gauss-Bonnet theorem. The first solution describes a regular Kerr black hole and an Einstein-Bumblebee black hole in low rotation. Nosso objetivo nesse trabalho é de estudar algumas propriedades importantes sobre buracos negros e wormoles. Entre os aspectos mais importantes que estudamos podemos dividir em dois temas principais. O primeiro diz respeito aos modos de oscilações em sistemas como buracos negros e wormholes. Estes sistemas devem emitir as oscilações quando são perturbados por algum campo externo. As amplitudes destas oscilações diminuem com tempo. Tipicamente chamamos estas oscilações de modos quasinormais (MQNs). O segundo aspecto que investigamos, que hoje vem despertando muito interesse dos pesquisadores, são as lentes gravitacionais. Então utilizamos o método semi-analítico WKB de terceira ordem e sexta ordem para calcular os MQNs de algumas métricas abordadas nesse trabalho. Para computar o desvio de luz devido a influência da lente gravitacional, utilizamos o teorema de Gauss-Bonnet quando consideramos pequenos desvios dos ângulos das trajetórias. As duas primeiras soluções que tratamos nesta tese foram construídas com base na chamada gravidade bumblebee, onde a presença de campo de violação de Lorentz contribui para a solução das equações de Einstein. A primeira descreve uma solução exata de buraco negro do tipo Schwarzschild e a segunda um wormhole transponível, ambos dependentes de um parâmetro de violação λ. No caso da solução de wormhole em gravidade bumblebee determinamos quais condições de energia são preservadas para sustentar esse tipo de wormhole. Ainda determinamos os valores que o parâmetro λ deve assumir, de modo a permitirmos calcular os MQNs usando o método WKB. Para solução de Schwarzschild em gravidade bumblebee também foi possível determinarmos os MQNs usando o método WKB de terceira e de sexta ordem. Com o teorema de Gauss-Bonnet encontramos uma expressão do desvio de luz para pequenos ângulos dessa vez na gravidade de Kalb-Ramond. Investigamos ainda duas soluções de buracos negros em rotação calculando expressões dos desvios dos ângulos de deflexão usando uma extensão do teorema de Gauss-Bonnet. A primeira solução descreve um buraco negro de Kerr regular e um buraco negro de Einstein-bumblebee em baixa rotação.

The problem of bending and scattering of light rays passing outside from the entrance to a wormhole with zero gravitational mass is considered. The process of ray capture by a wormhole as well as the process of formation of a shadow when illuminated by a standard screen is investigated. These mechanisms are also compared to the case of motion of light rays in the vicinity of the Schwarzschild black hole., Comment: 12 pages, 12 figures

We suggest two new scenarios of high-energy particle collisions in the background of a wormhole. In scenario 1, the novelty consists of the fact that the effect does not require two particles coming from different mouths. Instead, all such scenarios of high energy collisions develop, when an experimenter sends particles towards a wormhole from the same side of the throat. For static wormholes, this approach leads to indefinitely large energy in the center of mass. For rotating wormholes, it makes possible the super-Penrose process (unbounded energies measured at infinity). In scenario 2, one of colliding particles oscillates near the wormhole throat from the very beginning. In this sense, scenario 2 is intermediate between the standard one and scenario 1 since the particle under discussion does not come from infinity at all.

The Multiverse Response to the problem of evil has it that God made our universe because God makes every universe meeting a certain standard. The main problem for that response is that there’s no explanation for why God didn’t just keeping making duplicates of perfect universes. This paper introduces the ‘Multiactualities Response’, which says that God actualises every possible world that meets a certain standard of value. It avoids the corresponding problem about duplication because different propositions must always be true at distinct worlds. The Multiactualities Response nevertheless has its own problem, namely that it requires the possibility of multiple actual worlds. This paper argues that if we consider spacetimes with wormholes, we have good cause to think there can be multiple metaphysically privileged present moments; given a suitable analogy between time and modality, it follows that there can be multiple metaphysically privileged (i.e. actual) worlds. This paper includes an in–depth examination of the metaphysics of both the temporal and modal cases.

It is well known that static wormhole configurations in general relativity (GR) are possible only if matter threading the wormhole throat is &ldquo, exotic&rdquo, &mdash, i.e., violates a number of energy conditions. For this reason, it is impossible to construct static wormholes supported only by dust-like matter which satisfies all usual energy conditions. However, this is not the case for non-static configurations. In 1934, Tolman found a general solution describing the evolution of a spherical dust shell in GR. In this particular case, Tolman&rsquo, s solution describes the collapsing dust ball, the inner space-time structure of the ball corresponds to the Friedmann universe filled by a dust. In the present work we use the general Tolman&rsquo, s solution in order to construct a dynamic spherically symmetric wormhole solution in GR with dust-like matter. The solution constructed represents the collapsing dust ball with the inner wormhole space-time structure. It is worth noting that, with the dust-like matter, the ball is made of satisfies the usual energy conditions and cannot prevent the collapse. We discuss in detail the properties of the collapsing dust wormhole.

Are analyzed properties of Black Holes and Wormholes obtained by Einstein Theory of Gravitation (TGE) using the Schwarzschild, Eddington and Kruskal metrics. This article was written for undergraduate and graduate students of Physics. Key words: Einstein gravitation theory; black holes; wormholes.

We find a family of exact solutions to the Einstein&ndash, Maxwell equations for rotating cylindrically symmetric distributions of a perfect fluid with the equation of state p=w&rho, (|w|&lt, 1), carrying a circular electric current in the angular direction. This current creates a magnetic field along the z axis. Some of the solutions describe geometries resembling that of Melvin&rsquo, s static magnetic universe and contain a regular symmetry axis, while some others (in the case w&gt, 0) describe traversable wormhole geometries which do not contain a symmetry axis. Unlike Melvin&rsquo, s solution, those with rotation and a magnetic field cannot be vacuum and require a current. The wormhole solutions admit matching with flat-space regions on both sides of the throat, thus forming a cylindrical wormhole configuration potentially visible for distant observers residing in flat or weakly curved parts of space. The thin shells, located at junctions between the inner (wormhole) and outer (flat) regions, consist of matter satisfying the Weak Energy Condition under a proper choice of the free parameters of the model, which thus forms new examples of phantom-free wormhole models in general relativity. In the limit w&rarr, 1, the magnetic field tends to zero, and the wormhole model tends to the one obtained previously, where the source of gravity is stiff matter with the equation of state p=&rho

Agência 1 This work aims to present and discuss the optical analogue models used to study gravitational systems using condensed matter systems. The whole mathematical theory behind the construction of an analogue optical model and the explicit presentation of two analogue models are provided: Schwarzschild black hole and Morris-Thorne wormhole. A parametrization of such models is proposed in order to unify them through a free real parameter β that generates a family of new models, and open the possibility that some of theses new models could actually be analogue models.

A necessidade de tornar poços de petróleo cada vez mais eficientes, especialmente em ambientes de alto custo de produção, leva ao contínuo desenvolvimento de novas tecnologias. Em dezembro de 2019, cerca de 67% da produção de petróleo do Brasil era advinda de poços em rochas carbonáticas do Pré-Sal. A acidificação da matriz é uma técnica de estimulação frequentemente empregada em carbonatos para aumentar a produção, através da formação de canais de alta condutividade ao redor do poço, wormholes. Diversas características interferem no processo de acidificação, como a anisotropia, heterogeneidade, saturação de óleo, e velocidade da reação efetiva entre o fluido de tratamento e a rocha, tornando sua aplicação complexa. Os sistemas microemulsionados, constituídos por estruturas auto-associativas termodinamicamente estáveis e com baixa tensão superficial, são capazes controlar a taxa de transferência de massa e, portanto, interferir em processos reativos. Esses tipos de sistemas já foram abordados em alguns estudos, entretanto é um campo ainda pouco explorado. Esse trabalho visa desenvolver sistemas microemulsionados ácidos do tipo óleo em água e testar suas aplicações na acidificação da matriz em carbonato. Os sistemas de tratamento utilizaram como tensoativo o ALKONAT-L100, cotensoativo o n-butanol, fase apolar o xileno e fase polar soluções aquosas de HCl 1,54 %(m/m), 8,27 %(m/m) e 15 %(m/m). Os sistemas de tratamento microemulsionados foram caracterizados quanto a turbidez, pH, diâmetro de gotícula, condutividade, tensão superficial e estabilidade térmica. Foram testadas diferentes rochas carbonáticas, e escolheu-se o carbonato Indiana, uma rocha padrão em estudos de acidificação, para representar os reservatórios carbonáticos nesse estudo. As rochas carbonáticas foram caracterizadas quanto a composição, porosidade, permeabilidade e reatividade em ácido. Para avaliar a interação dos fluidos de tratamento com carbonato Indiana foram realizados estudos, tais como, influência da concentração de HCl e do tipo de sistemas de tratamento no comportamento da molhabilidade e reatividade superficial. Estudou-se, através de análise estatística, a influência da concentração de ácido, temperatura e tempo de reação na velocidade de reação em diferentes condições. Para estudar a viabilidade técnica da utilização dos sistemas microemulsionados, foram realizados ensaios para produção de curvas de Pore Volume to Breakthrough (PVBT) e posterior análise da morfologia dos padrões de dissolução por Micro-CT e RMN. Os resultados mostraram que mesmo para altas concentrações de HCl foram formados sistemas microemulsionados, ricos em água e pobres em matéria ativa, termicamente resistentes (acima de 100 oC). Os sistemas de tratamento contendo tensoativos, em especial os microemulsionados, causaram um expressivo aumento da molhabilidade da rocha á água e redução na reatividade superficial, em relação às soluções ácidas sem tensoativo. A velocidade de reação dos sistemas que não continham tensoativos são basicamente limitados pela concentração de HCl, independe da saturação, ao passo que para sistemas contendo tensoativos, o fator tempo também é significante. Os resultados de Micro-CT e RMN mostraram morfologias de wormholes efetivos quando foram utilizados sistemas microemulsionados. Dessa forma, os resultados obtidos demonstram que os sistemas microemulsionados possuem eficiência e boas perspectivas de aplicação no retardo da reação ácido-rocha na estimulação ácida de matriz carbonática. The necessity to make oil wells increasingly efficient, especially in conditions with high production costs, leads to continuous technological development in his area of knowledge. In December 2019, about 67% of Brazil's oil production came from wells in Pre-Salt carbonate rocks reservoirs. Matrix Acidification is a stimulation technique widely used in carbonates to increase its production as a result of the formation of high conductivity channels around the well, called wormholes. Several characteristics interfere in acidizing process as anisotropy, heterogeneity, oil saturation, and effective rock-acid reaction speed, making it complex technique. Microemulsion systems, formed by thermodynamically stable auto-associative structures that present low surface tension, can control mass and therefore interfere in reactive processes. These systems have already been subject of studies. However, this a field of study is still little explored. This work aims to develop acid oil in water microemulsion systems and test their applications in standard carbonate rock. These systems used ALKONAT-L100 as a surfactant, n-butanol as a co-surfactant, xylene as a nonpolar phase and HCl solutions as a polar phase (1.54 w/w%, 8.27 w/w%, and 15 w/w%). The acid microemulsion systems were characterized in ter terms of turbity, pH, drop size, conductivity, surface tension and thermal stability. Different carbonate rocks were tested, and Indiana carbonate, a standard rock in acidification studies, was chosen to represent the carbonate reservoirs in this study. The core samples were characterized in terms of composition, porosity, permeability, and reactivity in acid. In order of evaluate the interaction between the treatment fluids and Indiana carbonate, studies were carried out, such as the influence of the HCl concentration and the type of treatment systems on wettability and surface reactivity behavior. Experimental designs were carried out in different conditions to verify the influence of HCl concentration, temperature, and reaction time on the reaction speed. To study the technical feasibility of using microemulsified systems, tests were performed to produce Pore Volume to Breakthrough (PVBT) curves followed by subsequent dissolution patterns analyses by high resolution microtomography (Micro-CT) and NMR. The results showed that even at high HCl concentrations, microemulsion systems were formed close to the polar phase apex, and they were thermally resistant (at least 100 OC). The treatment systems containing surfactants, especially the microemulsified ones, caused a significant increase on the rock surface wettability to water and reduced the surface reactivity, compared with the ones with no surfactant. The speed of acid-rock of treatment systems that did not contain surfactants is basically limited by the concentration of HCl, regardless of saturation, whereas for systems containing surfactants, the time factor is also significant. The Micro-CT and NMR results showed effective wormholes morphologies when microemulsified systems were used. In this way, the results obtained demonstrate that microemulsified systems have efficiency and good prospects for application in retard acid-rock reaction in the acid stimulation in carbonates rocks.

We find an exact, rotating charged black hole solution within Eddington-inspired Born-Infeld gravity. To this end we employ a recently developed correspondence or {\it mapping} between modified gravity models built as scalars out of contractions of the metric with the Ricci tensor, and formulated in metric-affine spaces (Ricci-Based Gravity theories) and General Relativity. This way, starting from the Kerr-Newman solution, we show that this mapping bring us the axisymmetric solutions of Eddington-inspired Born-Infeld gravity coupled to a certain model of non-linear electrodynamics. We discuss the most relevant physical features of the solutions obtained this way, both in the spherically symmetric limit and in the fully rotating regime. Moreover, we further elaborate on the potential impact of this important technical progress for bringing closer the predictions of modified gravity with the astrophysical observations of compact objects and gravitational wave astronomy., 17 double column pages, 7 figures, revtex4-1 style

The “ER = EPR” conjecture, conceived by Maldacena and Susskind, is grounded on the notion that a gravitational theory in the bulk is dual to the corresponding quantum field theory on the boundary in accordance to the AdS/CFT correspondence. The conjecture pertains to the idea that Einstein-Rosen (ER) spacetime bridges and Einstein-Podolsky-Rosen (EPR) quantum entanglement may be considered as dually equivalent. Since ER bridges refer to the connectivity between black holes, the “ER = EPR” conjecture implies that black holes connected by ER bridges are entangled, and conversely, that entangled black holes are connected by ER bridges. However, the instance of the maximally entangled tripartite (GHZ) quantum state points to the necessity of devising a model of non-classical Planck scale ER bridges going beyond the standard description of these bridges in spacetime. Based on the topological structure of the maximally entangled GHZ state, we propose that a universal topological link, called the Borromean rings, furnishes a particular linking structure that is able to unravel the equavalence between entanglement and wormholes, and thus, to address the validity of the “ER = EPR” conjecture beyond the initial context of the AdS/CFT correspondence. As a consequence, we propose the explicit construction of distinguishable extensions of the smooth classical spacetime manifold taking place in the transition to the quantum gravity regime according to a naturally induced physical criterion of gravitational generic properties following from this intrinsic topological qualification of the “ER = EPR” conjecture.

We classified and studied the charged black hole and wormhole solutions in the Einstein–Maxwell system in the presence of a massless, real scalar field. The possible existence of charged black holes in general scalar–tensor theories was studied in Bronnikov et al., 1999; black holes and wormholes exist for a negative kinetic term for the scalar field. Using a conformal transformation, the static, spherically symmetric possible structures in the minimal coupled system are described. Besides wormholes and naked singularities, only a restricted class of black hole exists, exhibiting a horizon with an infinite surface and a timelike central singularity. The black holes and wormholes defined in the Einstein frame have some specificities with respect to the non-minimal coupling original frame, which are discussed in the text.

We consider the generalized Tolman solution of general relativity, describing the evolution of a spherical dust cloud in the presence of an external electric or magnetic field. The solution contains three arbitrary functions f(R), F(R) and τ0(R), where R is a radial coordinate in the comoving reference frame. The solution splits into three branches corresponding to hyperbolic (f&gt, 0), parabolic (f=0) and elliptic (f&lt, 0) types of motion. In such models, we study the possible existence of wormhole throats defined as spheres of minimum radius at a fixed time instant, and prove the existence of throats in the elliptic branch under certain conditions imposed on the arbitrary functions. It is further shown that the normal to a throat is a timelike vector (except for the instant of maximum expansion, when this vector is null), hence a throat is in general located in a T-region of space-time. Thus, if such a dust cloud is placed between two empty (Reissner–Nordström or Schwarzschild) space-time regions, the whole configuration is a black hole rather than a wormhole. However, dust clouds with throats can be inscribed into closed isotropic cosmological models filled with dust to form wormholes which exist for a finite period of time and experience expansion and contraction together with the corresponding cosmology. Explicit examples and numerical estimates are presented. The possible traversability of wormhole-like evolving dust layers is established by a numerical study of radial null geodesics.

Journal of high energy physics 1709(09), 074 (2017). doi:10.1007/JHEP09(2017)074, Recently two of the authors proposed a mechanism of vacuum energy sequester as a means of protecting the observable cosmological constant from quantum radiative corrections. The original proposal was based on using global Lagrange multipliers, but later a local formulation was provided. Subsequently other interesting claims of a different non-local approach to the cosmological constant problem were made, based again on global Lagrange multipliers. We examine some of these proposals and find their mutual relationship. We explain that the proposals which do not treat the cosmological constant counterterm as a dynamical variable require fine tunings to have acceptable solutions. Furthermore, the counterterm often needs to be retuned at every order in the loop expansion to cancel the radiative corrections to the cosmological constant, just like in standard GR. These observations are an important reminder of just how the proposal of vacuum energy sequester avoids such problems., Published by Springer, Berlin

The current paper is devoted to investigating wormhole solutions with an exponential gravity model in the background of f ( R ) theory. Spherically symmetric static spacetime geometry is chosen to explore wormhole solutions with anisotropic fluid source. The behavior of the traceless matter is studied by employing a particular equation of state to describe the important properties of the shape-function of the wormhole geometry. Furthermore, the energy conditions and stability analysis are done for two specific shape-functions. It is seen that the energy condition are to be violated for both of the shape-functions chosen here. It is concluded that our results are stable and realistic.

In this work we study and compare the features of gravitational entropy near the throat of transversable wormholes formed by exotic matter and wormholes in galactic halos. We have verified that gravitational entropy and entropy density of these wormholes in regions near their throats are indistinguishable for objects of same throat, despite the fact they are described by different metrics and by distinct energy-momentum tensors. We have found that the gravitational entropy density diverges near the throat for both cases, probably due to a non-trivial topology at this point, however allowing the interesting interpretation that a maximum flux of information can be carried through the throat of these wormholes. In addition, we have found that both are endowed with an entropic behaviour similar to Hawking-Bekenstein's entropy of non-rotating and null charge black holes., 18 pages, 3 figures

The friction stir weld (FSW) method was developed in 1991 by The Welding Institute (TWI) and is very useful for manufacturing components with low fusion weldability. The success of this relatively new technique is due, in part, to an appropriate combination of some parameters. In order to understand the influence of the parameters such as rotation speed, axial force, and welding velocity, simulations were carried out using the AISI 304L stainless steel. In this work, the process was considered to be a 3D non-Newtonian fluid and the heat input was calculated from the friction between the tool and the plate and from the plastic deformation. The thermal results were compared with the experimental results from the thermocouple measurements. Furthermore, the material flow was related to the formation of defects observed in the experimental welds. The results of the simulation were able to determine the temperature distribution and heat flow, as well as to predict defects in the welding. The simulated viscosity values enabled the prediction of the parameters most likely to cause the formation of flashes. In addition, the injection of inert particles into the model made it possible to predict the formation of wormholes.

We construct scalarized wormholes with a NUT charge in higher curvature theories. We consider both Einstein-scalar-Gauss-Bonnet and Einstein-scalar-Chern-Simons theories, following a recent paper by Brihaye et al. [1], where spontaneously scalarised Schwarzschild-NUT solutions were studied. By varying the coupling parameter and the scalar charge we determine the domain of existence of the scalarized nutty wormholes, and their dependence on the NUT charge. In the Gauss-Bonnet case the known set of scalarized wormholes [2] is reached in the limit of vanishing NUT charge. In the Chern-Simons case, however, the limit is peculiar, since with vanishing NUT charge the coupling constant diverges. We focus on scalarized nutty wormholes with a single throat and study their properties. All these scalarized nutty wormholes feature a critical polar angle, beyond which closed timelike curves are present., Comment: 14 pages, 4 figures

We investigate binary lenses with $1/r^n$ potentials in the asymmetric case with two lenses with different indexes $n$ and $m$. These kinds of potentials have been widely used in several contexts, ranging from galaxies with halos described by different power laws to lensing by wormholes or exotic matter. In this paper, we present a complete atlas of critical curves and caustics for mixed binaries, starting from the equal-strength case, and then exploring unequal-strength systems. We also calculate the transitions between all different topology regimes. Finally we find some useful analytic approximations for the wide binary case and for the extreme unequal-strength case., Comment: 25 pages, 18 figures, in press on Universe, special issue Gravitational Lensing and Optical Geometry: A Centennial Perspective

In this Ph.D. dissertation we study the emergence of black-hole and wormhole solutions in theframework of the Einstein-scalar-Gauss-Bonnet (EsGB) theory. Particularly we study a family oftheories where the coupling function f(φ) between the scalar field of the theory and the quadraticGauss-Bonnet gravitational term has an arbitrary form. At first, we analytically derive that theaforementioned family of theories may evade the constraints imposed by Bekenstein's No-Scalar Hair theorems and new solutions for black holes may be found. Then, using numerical integration methods we find solutions for black holes for many different forms of the coupling function. Also, we derive their physical characteristics namely their mass, scalar charge, horizon area and entropy as well.Subsequently, by introducing a cosmological constant in the theory we investigate the existence ofnovel black-hole solutions. Specifically, assuming that the cosmological constant may be positive ornegative we find numerical solutions which are asymptotically de Sitter or anti-de Sitter. In addition, as in the case of the asymptotically flat black holes, for each case we derive their physical characteristics. Finally, in the framework of the EsGB theory we derive novel wormhole solutions. The Gauss-Bonnet wormholes are traversable, may have a single or a double throat and do not demand the existence of exotic matter. Στην παρούσα Διδακτορική Διατριβή μελετάμε λύσεις Μαύρων Οπών και Σκουληκότρυπων στα πλαίσια της Γενικευμένης Θεωρίας Βαρύτητας Einstein-Scalar-Gauss-Bonnet (EsGB). Ειδικότερα μελετούμε μια οικογένεια θεωριών όπου η συνάρτηση σύζευξης $f(\f)$ ανάμεσα στο βαθμωτό πεδίο της θεωρίας και τον τετραγωνικό βαρυτικό όρο Gauss-Bonnet έχει εν γένει μια γενική μορφή. Αρχικά αποδεικνύουμε αναλυτικά ότι η οικογένεια αυτή των θεωριών δεν υπόκειται στους περιορισμούς που υποβάλουν τα No-Scalar Hair theorems του Bekenstein και νέες λύσεις ασυμπτωτικά επίπεδων μαύρων οπών μπορούν να βρεθούν. Στη συνέχεια, χρησιμοποιώντας μεθόδους αριθμητικής ολοκλήρωσης, προσδιορίζουμε νέες λύσεις μαύρων οπών (επιλέγοντας κάθε φορά συγκεκριμένη μορφή για τη συνάρτηση σύζευξης). Επιπλέον εξάγουμε τα χαρακτηριστικά τους, δηλαδή την μάζα τους, το βαθμωτό τους φορτίο, την επιφάνεια και την εντροπία τους. Έπειτα, εισάγοντας μια κοσμολογική σταθερά στην θεωρία ερευνούμε εκ νέου την ύπαρξη λύσεων μαύρων οπών. Συγκεκριμένα θεωρώντας πως η κοσμολογική σταθερά μπορεί να είναι θετική ή αρνητική βρίσκουμε αριθμητικές λύσεις οι οποίες είναι ασυμπτωτικά de Sitter ή anti-de Sitter αντίστοιχα. Επιπλέον όπως και στην περίπτωση των ασυμπτωτικά επίπεδων λύσεων, σε κάθε περίπτωση προσδιορίζουμε και ταχαρακτηριστικά των νέων αυτών λύσεων μαύρων οπών. Τέλος, στα πλαίσια της EsGB θεωρίαςβρίσκουμε λύσεις που περιγράφουν σκουληκότρυπες. Οι Gauss-Bonnet σκουληκότρυπες είναιδιασχίσιμες, μπορούν να έχουν μονό ή διπλό λαιμό και δεν απαιτούν την ύπαρξη εξωτικής ύλης σεκανένα σημείο του χωροχρόνου. 207 σ.

We study a traversable wormhole originated by a transformation over the 4D Dymnikova metric which describes analytic Black-Holes (BH). By using a transformation of coordinates which is adapted from the used in the Einstein-Rosen bridge, we study a specific family of geodesics in which a test particle with non-zero electric charge induces an effective magnetic monopole, that is perceived by observers outside the wormhole. Because the Riemannian geometry cannot explain the presence of magnetic monopoles, then we propose a torsional geometry in order to explore the possibility that magnetic monopoles can be geometrically induced. We obtain an expression that relates torsion and magnetic fields jointly with a Dirac-like expression for magnetic and electric charges, such that torsion makes possible define a fundamental length that provides a magnetic field and a spacetime discretization., Comment: Version accepted in EPJP

We argue that one can nucleate a traversable wormhole via a nonperturbative process in quantum gravity. To support this, we construct spacetimes in which there are instantons giving a finite probability for a test cosmic string to break and produce two particles on its ends. One should be able to replace the particles with small black holes with only small changes to the spacetime away from the horizons. The black holes are then created with their horizons identified, so this is an example of nucleating a wormhole. Unlike previous examples where the created black holes accelerate apart, in our case they remain essentially at rest. This is important since wormholes become harder and harder to make traversable as their mouths become widely separated, and since traversability can be destroyed by Unruh radiation. In our case, back-reaction from quantum fields can make the wormhole traversable., Comment: 24 pages, 6 Figs, v2: comment added and a few typos corrected

ispartof: JOURNAL OF HIGH ENERGY PHYSICS issue:10 status: published

In the Swampland philosophy of constraining EFTs from black hole mechanics we study charged black hole evaporation in de Sitter space. We establish how the black hole mass and charge change over time due to both Hawking radiation and Schwinger pair production as a function of the masses and charges of the elementary particles in the theory. We find a lower bound on the mass of charged particles by demanding that large charged black holes evaporate back to empty de Sitter space, in accordance with the thermal picture of the de Sitter static patch. This bound is satisfied by the charged spectrum of the Standard Model. We discuss phenomenological implications for the cosmological hierarchy problem and inflation. Enforcing the thermal picture also leads to a heuristic remnant argument for the Weak Gravity Conjecture in de Sitter space, where the usual kinematic arguments do not work. We also comment on a possible relation between WGC and universal bounds on equilibration times. All in all, charged black holes in de Sitter should make haste to evaporate, but they should not rush it., 38 pages + references, 5 figures, 1 conjecture v2: references added, minor modifications to text v3: corrected minor typos v4: corrected one typo

In general relativity, traversable wormholes are possible provided they do not represent shortcuts in the spacetime. Einstein equations, together with the achronal averaged null energy condition, demand to take longer for an observer to go through the wormhole than through the ambient space. This forbids wormholes from connecting two distant regions in the space. The situation is different when higher-curvature corrections are considered. Here, we construct a traversable wormhole solution connecting two asymptotically flat regions, otherwise disconnected. This geometry is an electrovacuum solution to the Lovelock theory of gravity coupled to an Abelian gauge field. The electric flux suffices to support the wormhole throat and to stabilize the solution. In fact, we show that, in contrast to other wormhole solutions previously found in this theory, the one constructed here turns out to be stable under scalar perturbations. We also consider wormholes in anti-de Sitter (AdS). We present a protection argument showing that, while stable traversable wormholes connecting two asymptotically locally AdS5 spaces do exist in the higher-curvature theory, the region of the parameter space where such solutions are admitted lies outside the causality bounds coming from AdS/CFT. Fil: Giribet, Gaston Enrique. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Rubín de Celis, Emilio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Simeone, Claudio Mauricio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina

This article describes the study of wormhole solutions in f(Q) gravity with noncommutative geometry. Here, we considered two different f(Q) models—a linear model f(Q)=αQ and an exponential model f(Q)=Q−α1−e−Q, where Q is the non-metricity and α is the model parameter. In addition, we discussed the existence of wormhole solutions with the help of the Gaussian and Lorentzian distributions of these linear and exponential models. We investigated the feasible solutions and graphically analyzed the different properties of these models by taking appropriate values for the parameter. Moreover, we used the Tolman–Oppenheimer–Volkov (TOV) equation to check the stability of the wormhole solutions that we obtained. Hence, we found that the wormhole solutions obtained with our models are physically capable and stable.

We discuss the possibility that the distribution of relic wormholes may possess fractal properties. Relic wormholes and their fractal distributions are predicted in a natural way by lattice quantum gravity models. This provides a new approach to some long standing problems. That is the nature of dark matter phenomena, the origin of Faber-Jackson and Tully-Fisher relations and the observed deficit of baryons. We derive corrections to the Newton’s potential caused by the presence of relic wormholes and show that the analysis of dark matter distribution in galaxies allows us to fix the parameters of the fractal distribution of wormholes.

The hypothesis is considered that the active galactic nuclei (AGNs) are wormhole (WH) mouths rather than supermassive black holes (SMBHs). We study the difference in the physical properties of such objects from those of AGNs with SMBH, as well as the the corresponding difference in observational data. Firstly, the radiative efficiency for some types of WHs (both static and rotating) can be significantly larger than the theoretical maximal value for the Kerr SMBHs. A number of AGNs is presented, for which the observational data can be interpreted as the result of the presence of WHs in them. Secondly, a sufficiently strong gamma radiation with a characteristic spectrum noticeably differing from that of AGNs jets, can be emitted from a static WH as a result of a collision of accreting flows of matter inside the WH.

Taking advantage of a previously developed method, which allows to map solutions of General Relativity into a broad family of theories of gravity based on the Ricci tensor (Ricci-based gravities), we find new exact analytical scalar field solutions by mapping the free-field static, spherically symmetric solution of General Relativity (GR) into quadratic $f(R)$ gravity and the Eddington-inspired Born-Infeld gravity. The obtained solutions have some distinctive feature below the would-be Schwarzschild radius of a configuration with the same mass, though in this case no horizon is present. The compact objects found include wormholes, compact balls, shells of energy with no interior, and a new kind of object which acts as a kind of wormhole membrane. The latter object has Euclidean topology but connects antipodal points of its surface by transferring particles and null rays across its interior in virtually zero affine time. We point out the relevance of these results regarding the existence of compact scalar field objects beyond General Relativity that may effectively act as black hole mimickers., 11 pages, revtex4-1 style

In this literature review we discus and describe the theoretically predicted phenomena known as wormholes, where two different regions of space-time are joined by a “throat” or a “bridge”. If information or even an observer could be sent through the wormhole we refer to it as traversable. We argue that traversable wormholes demands negative energy densities and display a number of different constructions found within the field. Among these the orgional construction by EinsteinRosen and Morris-Thornes discussion on traversability. We also give a overview of the current state of the field by presenting to more recently published papers: “Casimir Energy of a Long Wormhole Throat” av Luke Buther och “Traversable Wormholes via a Double Trace Deformation” av Ping Gao, Daniel Louis Jafferis och Aron C.Wall.

Carbonate rocks contain about 60 % of global oil and gas reserves. Stimulation of wells tapping into carbonate reservoirs is often performed using hydrochloric acid treatments based on the chemical reaction of hydrochloric acid with carbonate minerals. Carbonate reservoirs generally exhibit significant inhomogeneity, therefore the acid being injected into the formation causes uneven rock dissolution in the near-wellbore region, resulting in the emergence of highly conductive flow channels (wormholes) with complex geometry. They ensure a good hydrodynamic connection between the well and the formation. Each specific rock-acid compound system has an optimum injection rate which can help form long weakly ramified wormholes at minimum acid injection volume. The optimum injection rate value is influenced by many factors, such as pressure, temperature, acid concentration, solution composition, mineral composition of rock etc. As of today, laboratory research is the main method to determine the optimum parameters for treating the near-wellbore formation region with acid. The paper summarises the results of the analysis examining the influence of various factors on the optimum injection rate and the amount of injected pore volumes of an acid compound until a wormhole breakthrough. It is shown that the factors have a cumulative effect on the effectiveness of the acid treatment and have to be considered simultaneously in laboratory tests. The results of the performed analysis have been taken into account when planning further laboratory research. Within the design scope of hydrochloric acid treatments in wells of one of Iraq’s carbonate fields, laboratory tests have been conducted to assess the impact of acid concentration and injection rate on the effectiveness of acid stimulation in the conditions that were expected in case of the hydrochloric acid treatment. The determined injection parameters help obtain an optimum structure of wormholes at a minimum acid injection volume. The results of the performed research have been successfully used to design hydrochloric acid treatments in wells of the field under study.