Source Of Dark Energy Research Articles

Retraction Note: Emergent D-Instanton as a Source of Dark Energy

The author has retracted this article [1] because it significantly overlaps with a previously published article by Singh and Kar [2].

New Insights on Time and Quantum Gravity

According to Einstein, a universal time does not exist. But what if time is different than what we think of it? Cosmic Microvawe Background Radiation was accepted as a reference for a universal clock and a new time concept has been constructed. According to this new concept, time was tackled as two-dimensional having both a wavelength and a frequency. What our clocks measure is actually a derivation of the frequency of time. A relativistic time dilation actually corresponds to an increase in the wavelength of time. At the point where time wavelength and time frequency is equal, where light is positioned, quantum-world and macro-world are seperated. Gravity was redefined with respect to time and the new two dimensional time fabric of the universe was speculated to be the source of dark energy causing the universe to expand. According to this new point of view quantum realm and macro-world can be better understood. This new time concept provide a basis for our understanding of quantum gravity and provide the long-sought answers to well known problems of it. A prediction of the presented theory is that the universe will expand at various rates at different regions due to the fact that particular surroundings will create different gravities and cause a different gravity- time wavelength effect yielding various time delays for calculating this rate of expansion. Keywords: General Relativity, Gravitation, Time and frequency, Quantum mechanics DOI : 10.7176/APTA/83-08 Publication date : May 30 th 2020

Thermal dark energy

We present a novel source of dark energy, which is motivated by the prevalence of hidden sectors in string theory models and is consistent with all of the proposed swampland conjectures. Thermal effects hold a light hidden sector scalar at a point in field space that is not a minimum of its zero temperature potential. This leads to an effective "cosmological constant", with an equation of state $w=-1$, despite the scalar's zero temperature potential having only a 4D Minkowski or AdS vacuum. For scalar masses $\lesssim \mu$eV, which could be technically natural via sequestering, there are large regions of phenomenologically viable parameter space such that the induced vacuum energy matches the measured dark energy density. Additionally, in many models a standard cosmological history automatically leads to the scalar having the required initial conditions. We study the possible observational signals of such a model, including at fifth force experiments and through $\Delta N_{\rm eff}$ measurements. Similar dynamics that are active at earlier times could resolve the tension between different measurements of $H_0$ and can lead to a detectable stochastic gravitational wave background.

Collective Nouns for Mammals: A Bestiary

82 WILLIAM TODD SEABROOK Collective Nouns for Mammals: A Bestiary  Boars, A Singular Of KINGDOM: Animalia PHYLUM: Chordata CLASS: Mammalia ORDER: Artiodactyla FAMILY: Suidae GENUS: Sus SPECIES: S. scrofa There is only one boar in the animal kingdom and it is the only boar that has ever existed. It is an ancient creature, a creature singular unto itself. When you see a group of boars, you see multiple timelines, each layered over one another, no longer connected to its whole self, and forced to face the universe alone. Some are able to lead full lives. Others die quickly. But most are unable to cope with being severed from their singular identity and surrender to fracture again and again and again. With each fracture, their timelines become a bit shorter, slightly more divided. A singular of boars is the sight of an ancient creature being sliced away bit by bit, and eventually the boar will be so fractured that its being will not be able to hold its shape, dissolving into the void, singular once more. Buffalo, An Obstinacy Of KINGDOM: Animalia PHYLUM: Chordata CLASS: Mammalia ORDER: Artiodactyla 83 FAMILY: Bovidae GENUS: Bison It is notoriously difficult to move a buffalo. For ages, it was thought that their hooves were made of lead and their fur was laced with iron, but the truth is far stranger. When you see a buffalo, you are only seeing half of the animal. Under its hooves exists a mirrored version of itself, the two invisibly rooted together. As one moves, so does the other. With each step, a buffalo is required to rip itself in two, reconnecting only when its hooves land. As they stampede across a plain, their mirrors tear across the inner curve of the earth, joining and then severing from their bodies in a painful cycle. And when a buffalo dies, its two bodies grow into each other, the two versions becoming a single whole, a collection of itself, one sinking into the earth, the other rising toward the surface. Elephants, A Memory Of KINGDOM: Animalia PHYLUM: Chordata CLASS: Mammalia ORDER: Proboscidea FAMILY: Elephantidae GENERA: Loxodonta, Elephas SPECIES: L. africana, L. cyclotis, E. maximus Elephants have extraordinary memories. A single elephant can recall the entirety of its life, and a group can remember back to the dawn of time, recalling not just their own memories, but the collective memories of all living creatures. They are the witnesses to history. They can remember when the lands split apart, and when species divided into their own lines. They remember what it was like for the boar, who was there before the world fractured, and for dodos, who were there until they weren’t. Their memory goes all the way back to the moment of life’s creation, recalling the taste of the primordial soup when the first cell congealed into consciousness. The smell of the methanated air. The bright terror 84 of being alive. This memory is the one elephants cherish the most, softly blowing on its light so it is never extinguished. But as the number of elephants in the wild dwindles, so do the memories of the world. Already it is difficult to gather enough of them together to remember the time before man evolved, and the memories of the earliest animals, extinct for eons, grow hazier with every elephant that dies. Eventually they will slip below a critical mass, unable to remember the world as it once was, and the first memory of creation, the most precious memory of all, will be lost. Ferrets, A Fesnying Of KINGDOM: Animalia PHYLUM: Chordata SUBPHYLUM: Vertebrata CLASS: Mammalia ORDER: Carnivora FAMILY: Mustelidae GENUS: Mustela Ferrets are often considered the source of dark energy, the force that is responsible for expanding the universe at an accelerated rate. They have the peculiar ability to expend more energy than they ingest. The difference is small, so much so that over an entire lifetime it does not add up to even a single calorie’s worth of energy, but that is enough to create catastrophic consequences for the universe. If left unchecked, the furry creatures will push the universe past the point of gravitational collapse, dooming the cosmos...

Friedmann-Like Cosmological Equations for the Accelerated Expansion of the Universe

In recent papers [1] [2] [3], we framed suitable axioms for Space called Super Space by Wheeler [4]. Using our axioms in Newtonian formalism and considering the density of the universe to be constant in time, we showed in the above references that at t = 0 the radius of the universe need not be zero. And thus, we avoided the problem of singularity. We further showed that the Hubble factor is no longer constant in time and goes on decreasing as confirmed by experiments. We pointed out in the above references that Space is the source of dark energy which is responsible for the accelerated expansion of the universe. With a view to improving the above-mentioned results quantitatively, in this paper, we are discussing the consequences of our axioms using Einstein’s field equations of general theory of relativity. Friedmann-like Cosmological equations with Dark Energy built-in are derived. This derivation is obtained using Robertson-Walker line element and by introducing a suitable expression for Energy-Momentum tensor in terms of matter and Dark energy contents of the universe. The solutions of our cosmological equations obtained here, show that the radius of the universe cannot reach zero but has a minimum value and there is also maximum value for the radius of the universe. The inflationary expansion of the very early universe emerges from our theory.

New Insights into Time and Quantum Gravity

According to Einstein, a universal time does not exist. But what if time is different than what we think of it? Cosmic Microwave Background Radiation was accepted as a reference for a universal clock and a new time concept has been constructed. According to this new concept, time was tackled as two-dimensional having both a wavelength and a frequency. What our clocks measure is actually a derivation of the frequency of time. A relativistic time dilation actually corresponds to an increase in the wavelength of time. At the point where time wavelength and time frequency is equal, where light is positioned, quantum-world and macro- world are separated. Gravity was redefined with respect to time and the new two dimensional time fabric of the universe was speculated to be the source of dark energy causing the universe to expand. According to this new point of view quantum realm and macro-world can be better understood. This new time concept provide a basis for our understanding of quantum gravity and provide the long-sought answers to well known problems of it. A prediction of the presented theory is that the universe will expand at various rates at different regions due to the fact that particular surroundings will create different gravities and cause a different gravity- time wavelength effect yielding various time delays for calculating this rate of expansion.

Unified Dark Matter, Dark Energy and baryogenesis via a “cosmological wetting transition”

In a recent publication [1], a cosmological scenario featuring a scalar field, φ, that is a source for Dark Matter and Dark Energy has been proposed. In this paper, a concrete realization of that scenario is presented. As in many models of scalar-field driven Dark Energy, the effective Lagrangian of the field φ contains a potential proportional to e−φ/f. This potential is modulated in such a way that, in the absence of other matter fields, it has a local minimum at a small value of φ. Fluctuations of φ around this minimum give rise to a gas of dark-matter particles. The field φ is coupled to another scalar field χ in such a way that the minimum in the effective potential of φ disappears when, after a continuous phase transition accompanied by spontaneous symmetry breaking, χ develops a non-vanishing expectation value. This triggers slow growth of a homogeneous component of φ accompanied by the emergence of Dark Energy, a phenomenon analogous to the “wetting transition” in statistical mechanics. Inside regions of the Universe where the pressure is small and the energy density is large enough to stall expansion, in particular around galaxies and galaxy clusters, the phase transition in the state of χ does not take place, and a gas of cold dark-matter particles persists. The evolution of φ at very early times may tune the rate of baryogenesis.

Correction to: Emergent D-Instanton as a Source of Dark Energy

In the original article Supriya Kar was listed as a co-author without his permission. The sole author of this article is Deobrat Singh.

RETRACTED ARTICLE: Emergent D-Instanton as a Source of Dark Energy

We revisit a non-perturbative formulation leading to a vacuum created gravitational pair of (33)-brane by a Poincare dual higher form U (1) gauge theory on a D4 -brane. In particular, the analysis has revealed a dynamical geometric torsion H 3 for an on-shell Neveu-Schwarz (NS) form on a fat 4-brane. We argue that a D-instanton can be a viable candidate to incorporate the quintessence correction hidden to an emergent (3 + 1)-dimensional brane universe. It is shown that a dynamical non-perturbative correction may be realized with an axionic scalar QFT on an emergent anti 3-brane within a gravitational pair. The theoretical tool provokes thought to believe for an extra instantaneous dimension transverse to our classical brane-universe in an emergent scenario. Interestingly a D-instanton correction, sourced by an axion on an anti 3-brane, may serve as a potential candidate to explain the accelerated rate of expansion of our 3-brane universe and may provide a clue to the origin of dark energy.

Cosmographic nature of the early universe from extra dimensional perspective

In this study, making use of the f(R) theory of gravity in a D-dimensional Kaluza-Klein type framework, we discuss whether we need to assume additional dimensions in order to explain two stages (inflation and deceleration phases) of the universe. To reach this goal, we start with a higher dimensional form of the Friedmann equation written in the f(R) gravity. For the inflation era occurring after a beginning vacuum phase of the universe, we conclude that a 10-dimensional spacetime model is needed as predicted in the string theory. However, after using a fixed field condition, it is observed that additional dimensions are compactified on the standard four spacetime dimensions in the deceleration phase. Moreover, the additional dimensions may be responsible for the dynamics of the dark energy dominated era, that's why we can state that the source of dark energy may be the extra dimensions.

Periodic waveguided multiverse as a source of dark matter and dark energy

Sources of dark matter (DM) and dark energy (DE) could be co-existing standard-model (SM)-universes. The proposed four-dimensional (4D)-multiverse—periodic chain of identical (parallel, quasi-flat) three-dimensional (3D)-waveguides—mimics adjacent identical SM-like universes, immersed in global 4D-Euclidean space. The quasi-classical Maxwellian-like waveguided normal modes simultaneously create quantized 3D-rest-mass particles (from electron to higher masses) with co-emergent basic physical laws (special relativity, quantum mechanics) plus weak Newtonian gravity with equivalence principle. The basic novelties are: The nearest adjacent SM-like-universes show evident charge-parity-time plus ±Mgr (gravity charges) symmetries—matter–antimatter antigravity—the dark energy nature; the nearest even (odd) 3D-universes become SM-decoupled, DM-like gravitating, disclosing the dark matter and DM–DE fine-tuning nature. The proposed corresponding weightless superfluid vacuum-medium concept discloses the Planckian h, light speed C constants nature as propagating massless quasiparticles-magnons—attractive–repulsive odd spin-1 photons and spin-3 gravitons; explains the quantum double-split, entanglement, etc phenomena and the 3D-waveguided quasi-optical nature of the least-action principle. This concept predicts: The matter–antimatter antigravity; only antimatter (the only SM mediator between matter and dark matter) able detect dark matter particles; the only possibility create dark matter particles is the antiparticles–antiparticles collision (never done), realizable even in low-energy colliders.

Bianchi type III cosmological model with hybrid scale factor in the presence of Van der Waals fluid in Lyra manifold

The search for the existence of Lyra manifold in a hybrid universe interacting with Van der Waals fluid using Bianchi type III metric is presented in this paper. To find the exact cosmological solutions, we use certain physical relations between the metric potentials and the average scale factor is assumed to be [Formula: see text] (see Ref. 1) describing the hybrid character of scale factor with the generation of a model of transitioning phase from early decelerating to the present accelerating universe. In this model, when we investigate further about the role of the Van der Waals fluid with Lyra geometry, interestingly, we found that this universe behaves as one containing with dark energy and at the late stage a part of the dark energy behaves as phantom type. This part being generated by the Lyra manifold itself may be taken as a source of dark energy. Some physical as well as geometrical aspects of the model universe are also presented.

A new model of universe which can explaine source of dark energy

A new model of universe which can explaine source of dark energy

Accelerated cosmos in a nonextensive setup

Here, we consider a flat FRW universe whose its horizon entropy meets the R\'enyi entropy of non-extensive systems. In our model, the ordinary energy-momentum conservation law is not always valid. By applying the Clausius relation as well as the Cai-Kim temperature to the apparent horizon of a flat FRW universe, we obtain modified Friedmann equations. Fitting the model to the observational data on current accelerated universe, some values for the model parameters are also addressed. Our study shows that the current accelerating phase of universe expansion may be described by a geometrical fluid, originated from the non-extensive aspects of geometry, which models a varying dark energy source interacting with matter field in the Rastall way. Moreover, our results indicate that the probable non-extensive features of spacetime may also be used to model a varying dark energy source which does not interact with matter field, and is compatible with the current accelerated phase of universe.

Whether Lyra’s Manifold Itself is aHidden Source of Dark Energy

In the course of investigation of some interesting cosmic string universes in the five dimensional Lyra manifold it is excitingly found that the geometry itself of Lyra manifold behaves as a new source of dark energy and this energy takes a form similar to that of quintessence in most of the cases, though in one case the dark energy comes out to be that of the cosmological constant type. The behaviour of the universes and their contribution to the process of evolution are examined. Further study of such type of universes will be very helpful in explaining the present accelerated expansion behaviour of the universe.

On neutrino masses and source of dark energy

We propose a Higgs-extended model in which neutrinos naturally acquire tiny Majorana masses as constrained by the electroweak precision data, while the associated pseudo Nambu–Goldstone boson serves as an attractive candidate for dark enegy.

A causal viscous cosmology without singularities

An isotropic and homogeneous cosmological model with a source of dark energy is studied. That source is simulated with a viscous relativistic fluid with minimal causal correction. In this model the restrictions on the parameters coming from the following conditions are analized: a) energy density without singularities along time, b) scale factor increasing with time, c) universe accelerated at present time, d) state equation for dark energy with "w" bounded and close to -1. It is found that those conditions are satified for the following two cases. i) When the transport coefficient ({\tau}_{{\Pi}}), associated to the causal correction, is negative, with the aditional restriction {\zeta}|{\tau}_{{\Pi}}|>2/3, where {\zeta} is the relativistic bulk viscosity coefficient. The state equation is in the "phantom" energy sector. ii) For {\tau}_{{\Pi}} positive, in the "k-essence" sector. It is performed an exact calculation for the case where the equation of state is constant, finding that option (ii) is favored in relation to (i), because in (ii) the entropy is always increasing, while this does no happen in (i).

Gaugessence: a dark energy model with early time radiation-like equation of state

In this work, we study a new quintessence model associated with non-Abelian gauge fields, minimally coupled to Einstein gravity. This gauge theory has been recently introduced and studied as an inflationary model, called gauge-flation. Here, however, we are interested in the late time cosmology of the model in the presence of matter and radiation to explain the present time accelerating Universe. During the radiation and matter eras, the gauge field tracks radiation and basically acts like a dark radiation sector. As we approach lower redshifts, the dark component takes the form of a dark energy source which eventually becomes the dominate part of the energy budget of the Universe. Due to the tracking feature of our model, solutions with different initial values are attracted to a common trajectory. The existence of early dark radiation is a robust prediction of our model which contributes to the effective number of relativistic species, $N_{\rm eff}$ and has its own interesting observational features.

Dark Energy and Estimate of Cosmological Constant from String Theory

The observation that expansion of our universe is accelerating suggests the existence of an unknown energy source, dark energy. The observed large-scale structure of our universe indicates the existence of an unknown matter source, dark matter. Cosmological constant, a constant term related to the vacuum energy appearing in the equation of gravitational field, is the simplest possible form of dark energy. String theory is one of the few mathematically consistent theories that can unify quantum physics and general relativity. In this work, we present a new way to derive and interpret string theory. We show that this new interpretation of string theory can explain the source of dark energy and dark matter. It may provide a way to calculate cosmological constant consistent with the current data.

Bianchi type VI0 generalized ghost pilgrim dark energy model in Brans–Dicke theory of gravitation

In this paper, we solve Brans–Dicke (BD) theory (Phys. Rev. D, 24, 925) field equations for anisotropic Bianchi type VI0 space–time and discuss evolution of the expanding Universe. Here, we consider pressureless fluid and isotropic generalized ghost pilgrim dark energy as the source of matter and dark energy, respectively. To get the determinate solution of the field equations we have used (i) scalar expansion proportional to the shear scalar and (ii) scalar field (in BD theory) proportional to average scale factor of the model. Some physical and geometrical properties of the model are also discussed.