Publications related to Cosmology (10,000)

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In the present work, we solve the nonlinear Helmholtz differential equation by means of the Jacobi elliptic functions in the context of the problem of the deflection of light in the gravitational field of the Sun and taking into account the cosmological constant in the Einstein equations. The proposed methodology can be of great help for students a...

Building on the foundational The Affect Theory Reader, this new volume gathers together contemporary scholarship that highlights and interrogates the contemporary state of affect inquiry. Unsettling what might be too readily taken-for-granted assumptions in affect theory, The Affect Theory Reader 2 extends and challenges how contemporary theories o...

Traditional ancestral knowledge: an elaboration of cases and problems Modalidad: Taller Duración: 120 minutos Línea temática: Perspectivas en diversidad, diferencia e interculturalidad en la educación en ciencias. Responsables: Silvio Daza Rosales 1 y José Rafael Arrieta Vergara 2 Resumen: El siguiente taller propone un esquema de trabajo en el aul...

In the Indian context, it is impossible to view any “body”, human or animal,
divorced from its caste-based cultural milieu. They embody a specific semiotics
in the cosmology of the everyday social relations of production. Some
bodies, whether human or animal, enjoy a privileged status with greater
access to resources, whereas an untouchable body is...

We consider a real scalar field in de Sitter background and compute its thermal propagators. We propose that in a dS/CFT context, nontrivial thermal effects as seen by an `outside’ observer can be encoded in the anomalous dimensions of the d=3 Ising model. One of these anomalous dimensions, the critical exponent η, completely fixes a number of cosm...

We present differential double-copy relations between gluon and graviton three-point functions in AdSd+1. We introduce a set of differential operators in anti–de Sitter (AdS) that naturally generalize on shell kinematics of scattering amplitudes in flat space. This provides a way to construct AdS correlators by replacing the kinematic variables of...

We prove the conditions under which scaling cosmologies are inevitable late-time attractors of multifield multiexponential potentials, independently of initial conditions. The advantage of such scaling cosmologies is that the time dependence of the fields and of the scale factor is known analytically, thus allowing late-time observables to be deter...

Ricci-flat solutions to Einstein's equations in four dimensions are obtained as the flat limit of Einstein spacetimes with negative cosmological constant. In the limiting process, the anti-de Sitter energy--momentum tensor is expanded in Laurent series in powers of the cosmological constant, endowing the system with the infinite number of boundary...

We consider the quantized bi-scalar gravity, which may serve as a locally Lorentz invariant cosmological model with varying speed of light and varying gravitational constant. The equation governing the quantum regime for the case of homogeneous and isotropic cosmological setup is a Dirac-like equation which replaces the standard Wheeler–DeWitt equa...

We investigate whether an accelerating universe can be realized as an asymptotic late-time solution of Friedmann–Lemaître–Robertson–Walker (FLRW)-cosmology with multifield multiexponential potentials. Late-time cosmological solutions exhibit a universal behavior which enables us to bound the rate of time variation of the Hubble parameter. In string...

Assuming that the energy density of super-heavy particles matches that of dark matter observed today, tight constraints on the couplings governing the decay process are presented as a function of the particle mass. These constraints are obtained from the lack of signatures that would be suggestive of decaying super-heavy X X particles in the data o...

Recently, the scalar-tensor representation of (,) gravity was used to explore gravitationally induced particle production/annihilation. Using the framework of irreversible thermodynamics of open systems in the presence of matter creation/annihilation, the physical and cosmological consequences of this setup were investigated in detail. In this pape...

The cosmic large-scale structure (LSS) provides a unique testing ground for connecting fundamental physics to astronomical observations. Modeling the LSS requires numerical-body simulations or perturbative techniques that both come with distinct shortcomings. Here we present the first unified numerical approach, enabled by new time integration and...

We study the evolution of magnetic fields coupled with chiral fermion asymmetry in the framework of chiral magnetohydrodynamics with zero initial total chirality. The initial magnetic field has a turbulent spectrum peaking at a certain characteristic scale and is fully helical with positive helicity. The initial chiral chemical potential is spatial...

An analysis of contemporary Cosmology is presented, with the aim of identifying the elements present in it according to the scientific program structure created by I. Lakatos. We look at some modern controversies from this point of view and clarify the meaning of issues related to them within this context.

We use the dispersion measure (DM) and redshift measurements of 24 localized fast radio bursts (FRBs) to compare cosmological models and investigate the Hubble tension. Setting a flat prior on the DM contribution from the Milky Way’s halo, DM halo MW ∈ [ 5 , 80 ] pc cm − 3 , the best fit for flat ΛCDM is obtained with a Hubble constant H 0 = 95.8 −...

We study the evolution and production of axion dark matter in a universe model with two scale factors corresponding to different patches of the universe. The interaction between patches is described through a deformed Poisson bracket structure. The first part of the present paper is devoted to a review of the results reported in previous works conc...

The gravitational lens system PS J0147+4630 (Andromeda’s Parachute) consists of four quasar images ABCD and a lensing galaxy. We obtained r -band light curves of ABCD in the 2017−2022 period from monitoring with two 2 m class telescopes. Applying state-of-the-art curve-shifting algorithms to these light curves led to measurements of time delays bet...

We present a dark fluid model described as a non-viscous, non-relativistic, rotating, and self-gravitating fluid. We assume that the system has spherical symmetry and that the matter can be described by the polytropic equation of state. The induced coupled nonlinear partial differential system of equations was solved using a self-similar time-depen...

The question is posed whether the prevailing theory of redshift-as being due entirely to Doppler shifts and motion, might instead or jointly be caused by the nonlinear interactions of light in stellar and galactic environments, where nonlinear effects such as stimulated Raman scattering may play a role in redshift that could very well influence the...

The H0 Award. A History: Professor Adam G. RIESS, Nobel prize in Physics (2011), is awarded the Chalonge Medal, Héctor de Vega Medal, and H0 Award 2023, for his relentless clever work and deep discoveries regarding the expansion rate of the Universe, a puzzle at the center of Cosmology and LambdaCDM showing the Model is currently challenged to conn...

This study explores the impact of antisymmetric tensor effects on spherically symmetric black holes, investigating photon spheres, shadows, and quasinormal frequencies in relation to a parameter which triggers the Lorentz symmetry breaking. We examine these configurations without and with the presence of a cosmological constant. In the first scenar...

The present analysis deals with the study of the f(Q,T) theory of gravity, which was recently considered by many cosmologists. In this theory of gravity, the action is taken as an arbitrary function f(Q,T), where Q is non-metricity and T is the trace of the energy–momentum tensor for matter fluid. In this study, we took two different forms of the f...

We show that the Friedmann–Lemaître–Robertson–Walker (FLRW) framework has an instability towards the growth of fluid flow anisotropies, even if the Universe is accelerating. This flow (tilt) instability in the matter sector is invisible to Cosmic No-Hair Theorem-like arguments, which typically only flag shear anisotropies in the metric. We illustra...

Einstein’s general theory of relativity from 1915¹ remains the most successful description of gravitation. From the 1919 solar eclipse² to the observation of gravitational waves³, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the...

In the almost empty Universe (with almost no matter in it), stochastic gravitational waves (SGW) of finite amplitude produce a de Sitter regime as a solution, which is invariant with respect to the Wick rotation. Asymptotically, super horizon SGWs do not "feel" difference between Lorentzian and Euclidean space-time and belong simultaneously to both...

H_0 The Expansion History of the Universe. Professor Adam G. RIESS, Nobel prize in Physics (2011), is awarded the Chalonge Medal, Héctor de Vega Medal, and H0 Award 2023, for his relentless clever work and deep discoveries regarding the expansion rate of the Universe, a puzzle at the center of Cosmology and LambdaCDM showing the Model is currently...

These authors contributed equally to this work. Abstract: The accelerated expansion of the universe during recent times is well known in cosmology, whereas during early times, there was decelerated expansion. The ΛCDM model is consistent with most observations, but there are some issues with it. In addition, the transition from early deceleration t...

A presente pesquisa identifica como práxis ecofeministas podem colaborar para a construção de sociedades ecológicas e anti-patriarcais diante da intensificação da crise climática e do aumento da violência contra mulheres no contexto neoliberal. Buscou-se identificar a relação entre ambos os fenômenos e explicar a formação da estrutura de classes tr...

Recently different cosmological measurements have shown a tension in the value of the Hubble constant, $$H_0.$$ H 0 . Assuming the $$\Lambda $$ Λ CDM model, the Planck satellite mission has inferred the Hubble constant from the cosmic microwave background (CMB) anisotropies to be $$H_0 = 67.4 \pm 0.5 \, \text {km} \, \text {s}^{-1} \, \text {Mpc}^{...

A bstract
We propose a new freeze-in dark matter candidate which feebly couples to the standard model charged leptons. The feeble interactions allow it (i) to freeze-in from the Standard Model thermal bath with its relic density being either a fraction or the entirety of the observed dark matter density and (ii) to radiatively decay to two photons...

The main objective of this paper is to redirect the attention of the African performer, the writer, the theatre artist, theatre enthusiast and commentator to what constitutes an African thought in the process of African inquiry and creative production. To the African performer as well as his critic; to the African theatre enthusiast as well as its...

We conduct a Bayesian analysis of recent observational datasets, specifically the Cosmic Chronometers (CC) dataset and Pantheon samples, to investigate the evolution of the EoS parameter in dark energy models. Our study focused on the effective EoS parameter, which is described by the parametric form \(\omega _{eff}=-\frac{1}{1+m(1+z)^n}\), where m...

The metaphysical lure of Wallace Stevens’s poetry has tantalized readers for decades yet refuses to be pinned down, evading categories like idealism, realism, and anti-realism. Throughout his entire career from Harmonium (1923) to The Rock (1954), Stevens was haunted by the “one” and the possibilities of change. Does change contradict oneness? Can...

According to the standard interpretation of Einstein’s field equations, gravity consists of mass-energy curving spacetime, and an additional physical force or entity—denoted by Λ (the ‘cosmological constant’)—is responsible for the Universe’s metric-expansion. Although General Relativity’s direct predictions have been systematically confirmed, the...

We consider an isotropic homogeneous cosmological model with five interacting elements: first, the dynamic aether presented by a unit timelike vector field; second, the pseudoscalar field describing an axionic component of the dark matter; third, the cosmic dark energy, described by a rheologic fluid; fourth, the non-axionic dark matter coupled to...

Cosmic voids are the largest and most underdense structures in the Universe. Their properties have been shown to encode precious information about the laws and constituents of the Universe. We show that machine-learning techniques can unlock the information in void features for cosmological parameter inference. We rely on thousands of void catalogs...

A bstract
The QCD axion can be formulated in a dual description as a massive 2-form field. In this picture, the QCD axion quality problem translates into the question if there are additional 3-forms coupled to the axion other than the QCD 3-form that emerges at low energy. If such forms exist, the quality problem can be resolved via the introductio...

We construct the first four-dimensional multiple black hole solution of general relativity with a positive cosmological constant. The solution consists of two static black holes whose gravitational attraction is balanced by the cosmic expansion. These static binaries provide the first four-dimensional example of nonuniqueness in general relativity...

A bstract
We explore the possibility of embedding thermal leptogenesis within a first-order phase transition (FOPT) such that RHNs remain massless until a FOPT arises. Their sudden and violent mass gain allows the neutrinos to become thermally decoupled, and the lepton asymmetry generated from their decay can be, in principle, free from the strong...

We study the production of a beyond the Standard Model (BSM) free-streaming relativistic particles which contribute to Neff and investigate how much the predictions for the inflationary analysis change. We consider inflaton decay as the source of this dark radiation (DR) and use the cosmic microwave background (CMB) data from Planck-2018 to constra...

Based on Padmanabhan's theory, the spatial expansion of the Universe can be explained by the emergence of space as cosmic time progresses. To further explore this idea, we have developed fractional-fractal Friedmann and Raychaudhuri equations for an isotropic and homogeneous universe. Our analysis has also delved into how Padmanabhan's concept fits...

Einstein spent his latter years attempting to unify gravitation with electromagnetism but lacked several conceptual notions, perspectives, and cosmological data in order to successfully merge them

Esta pesquisa tem como objetivo analisar as canções do grupo Minha Raízes, oriundo de populações tradicionais do Baixo Madeira especificamente da comunidade de Nazaré orientado por pensadores como Adorno (2017) e Cunha (2009). Assim se fez uma coleta de dados por meio de entrevistas com os membros do grupo Minha Raízes, se transcreveu todas as canç...

This article aims to provide a comprehensive exploration of nine pivotal natural principles and their significance in understanding the fundamental laws governing the cosmos. By offering mathematical expressions, real-world examples, and a unifying equation, the purpose is to elucidate the intricate interplay of these principles, shedding light on...

However it can be applied in QCD only to rather rare collisions with large transferred momenta (or masses) where the coupling strength becomes small due to the asymptotic freedom property, specific for QCD. It cannot be applied to main bulk of "soft" hadronic interactions with low transferred momenta because the coupling constant becomes large. The...

The formal ontologies that organize underlying data are extensively utilized by the Semantic Web to achieve complete and portable machine comprehension. Because of this, the Semantic Web's success is heavily dependent on the spread of ontologies, which calls for quick and simple ontology architecture and the avoidance of a knowledge accumulation bo...

The Eddington-inspired Born-Infeld (EiBI) theory of gravity is an emerging post-Newtonian theory equivalent to Einstein's General Relativity (GTR) in vacuum. It introduces modifications to the self-gravitating potential of an astrofluid in dense matter environments. In the non-relativistic Newtonian limit, it introduces an additional correction ter...

We derive the first analytical formula for the density of "Dark Matter" (DM) at all length scales, thus also for the rotation curves of stars in galaxies, for the baryonic Tully–Fisher relation and for planetary systems, from Einstein's equations (EE) and classical approximations, in agreement with observations. DM is defined in Part I as the energ...

In this paper will be presented the equations of Unified Physics. The beautiful equations of the unification of the fundamental interactions. We calculate the unity formulas that connect the coupling constants of the fundamental forces. These equations are applicable for all energy scales. Also we present the unification of atomic physics and cosmo...

It is discussed in detail the complete mathematical model of gravitational lensing on a single cosmic string (CS) of general shape and position with respect to the line of sight. CS are one-dimensional extended objects assuredly predicted by modern cosmology. The presence of CS changes the global geometry of the Universe, could clarify the properti...

We use high-resolution zoom-in cosmological simulations to model outflow triggered by radiation and thermal drivers around the central mass accumulation during direct collapse within the dark matter (DM) halo. The maximal resolution is 1.3 × 10 ⁻⁵ pc, and no restrictions are put on the geometry of the inflow/outflow. The central mass is considered...

We analyze the parity-odd correlators $$\langle JJO\rangle _{odd},$$ ⟨ J J O ⟩ odd , $$\langle JJT\rangle _{odd},$$ ⟨ J J T ⟩ odd , $$\langle TTO\rangle _{odd}$$ ⟨ T T O ⟩ odd and $$\langle TTT\rangle _{odd}$$ ⟨ T T T ⟩ odd in momentum space, constrained by conformal Ward identities, extending our former investigation of the parity-odd chiral anoma...

A bstract
The P - V phase transition of the FRW (Friedmann-Robertson-Walker) universe with a perfect fluid has recently been investigated, revealing that the four critical exponents near the critical point are consistent with the values predicted by mean field theory. Notably, the coexistence phase of the P - V phase transition in the FRW universe...

This article presents a novel parametrization of the deceleration parameter (DP) to investigate the cosmological scenario. The newly proposed parametric form of the DP is both physically plausible and model-independent. Constrained by a combined dataset of 31 cosmic chronometers (CC) data points, 26 non-correlated baryonic acoustic oscillations (BA...

We present results on the morphological and structural evolution of a total of 3956 galaxies observed with JWST at 1.5 < z < 6.5 in the JWST CEERS observations that overlap with the CANDELS EGS field. This is the biggest visually classified sample observed with JWST yet, ∼20 times larger than previous studies, and allows us to examine in detail how...

A bstract
We study various aspects of the Carroll limit in which the speed of light is sent to zero. A large part of this paper is devoted to the quantization of Carroll field theories. We show that these exhibit infinite degeneracies in the spectrum and may suffer from non-normalizable ground states. As a consequence, partition functions of Carrol...

Nowadays there is a new challenge among scientists, all of us know dark energy spreads the universe by constant index, but the big question is whether the universe expanding without stopping. I am not agreeing, because on the other side, we have dark matter and we know the force of dark matter and dark energy are opposite of each other. In this art...

This article presents a scientific framework that investigates the hypothesis positing electrons as miniature black holes. By elucidating a profound mathematical foundation, we reveal intriguing connections between particle physics and cosmology. This framework encompasses the Charge-Mass Relationship, Self-Energy of a Ring Structure, Kerr-Newman M...

In this work, we investigate for the first time Nariai-like black hole solutions in four dimensional space time with spherical symmetry in the context of scale-dependent gravity. In particular, we construct self-consistent solutions in such a way that the classical one that coming from Einstein theory) is also contained into our new results. We sta...

Existents could be matter or antimatter, but only cellular matters are considered as having life and living entities. Critical observations indicated that cellular matter like zygote and non-cellular matter like the Universe grow to form specialized self-organized parts and systems. This research was aimed at re-investigating the concepts of "life"...

This article presents a scientific framework that investigates the hypothesis positing electrons as miniature black holes. By elucidating a profound mathematical foundation, we reveal intriguing connections between particle physics and cosmology. This framework encompasses the Charge-Mass Relationship, Self-Energy of a Ring Structure, Kerr-Newman M...

This paper explores new neutron star models based on spherically symmetric space–time. We take into account the gravitational effects of f(T,T) gravity, in which T is the torsion and T is the trace of the energy–momentum tensor. Field equations are evaluated by incorporating the off-diagonal tetrad. In this paper, we discuss the detailed properties...

A process of idea filtration in two distinct streams of physics i.e., 1) The dimensionality perspective of spacetime, and 2) The quantum perspective – leads us to an understanding of what might be a true reality of all that we perceive. The conclusions arrived at in this paper are a bit perplexing in the sense that our perceived reality could be a...

The analysis of excursion sets in imaging data is essential to a wide range of scientific disciplines such as neuroimaging, climatology, and cosmology. Despite growing literature, there is little published concerning the comparison of processes that have been sampled across the same spatial region but which reflect different study conditions. Given...

In the present work gravity is considered both in the discrete form (within the scope of the Regge Calculus) and at the limiting transition to a continuous pattern in the non-perturbative regime. Quantum-gravitational corrections have been found for all the fundamental quantities in the case when space-time foam at Planck's scales comprises black h...

Based on Torsion as given by de Sabbata and Sirvaram, Erice 1990. The 1990 article claims that Torsion cancels Cosmological vacuum energy. We consider if relic black holes at the start of inflation may allow for the observed cosmological constant. Using the 1990 text if thermal energy is used at start of inflation creates conceptual issues, whereas...

In Bantu cosmology mountain tops have special importance for prayer to God. A polarity exists with the sites of water-as prime realm of spirits. Ritual and divinatory access to both types of sites provides different forms of authority. In prayer for rain both are connected.

This thesis addresses the practical nature and necessity of assumptions for the construction of classical general relativity and its application to Friedmann-Robertson-Walker cosmology. The approach taken is in the realm of mathematical physics with particular emphasis on linearized gravity and stability analysis. The e¤ective radius of the observa...

Available inventories of baryonic mass in the universe are based largely on galactic data and empirical calculations made >20 years ago. Values falling below cosmological estimates underlie proposals that certain rarified gassy regions could have extremely high T, which motivated absorption measurements and hydrodynamic models. Yet, the shortfall r...

Meaning and no-soul, When a Free Neutron Decays, Early Nuclear Experiments and the Standard Model; A Reexamination of TCT, Modern Cosmology, and Potential Reconciliation; John, Revelation, and More; Angels, Demons, Souls, and Temporal Physics

A bstract
Inflation correlators with one-loop massive exchange encode rich information about the dynamics of the massive loop particles. Their nonanalytic behavior in certain soft limits leads to characteristic oscillatory pattern, which is the leading signal of many particle models of cosmological collider physics. In this work, we investigate sys...

A bstract
In this paper we revisit a generalised crossing equation that follows from harmonic analysis on the conformal group, and is of particular interest for the cosmological bootstrap programme. We present an exact solution to this equation, for dimensions two or higher, in terms of 6j symbols of the Euclidean conformal group, and discuss its r...

We investigate the thermodynamic properties of the Hayward regular black hole using both Euclidean path integral and Hamiltonian methods, in asymptotically anti-de Sitter, Minkowski, and de Sitter spacetimes. With the inclusion of matter fields which act as a source for the regular black hole geometry, an effective temperature emerges that differs...

Dark sector theories naturally lead to multicomponent scenarios for dark matter where a subcomponent can dissipate energy through self-interactions, allowing it to efficiently cool inside galaxies. We present the first cosmological hydrodynamical simulations of Milky Way analogs where the majority of dark matter is collisionless cold dark matter (C...

In this work we have considered a quintom cosmological model with generalised Galileon corrections in the scalar tensor theories of gravitation. After proposing the corresponding action of the cosmological model we have deduced the Klein-Gordon equations and the modified Friedmann relations. By introducing the auxiliary variables we have described...

Ultralight axion-like particles are well-motivated relics that might compose the cosmological dark matter and source anomalous time-dependent magnetic fields. We report on terrestrial bounds from the Noble And Alkali Spin Detectors for Ultralight Coherent darK matter (NASDUCK) collaboration on the coupling of axion-like particles to neutrons and pr...

One of the key open questions in cosmology is the nature of sources that completed cosmological hydrogen reionization at z ∼ 5.2. High- z primeval galaxies have been long considered the main drivers of reionization, with a minor role played by high- z active galactic nuclei (AGN). However, in order to confirm this scenario, it is fundamental to mea...

We present, for the first time, a complete treatment of strongly interacting dark matter capture in planets, taking Earth as an example. We focus on light dark matter and the heating of Earth by dark matter annihilation, addressing a number of crucial dynamical processes which have been overlooked, such as the “ping-pong effect” during dark matter...

We consider the screening of the axio-dilaton fields when both the dilaton and the axion couple to matter with Yukawa couplings. We analyze the screening of the dilaton in the vicinity of a compact object and find that this can only take place when special boundary conditions at infinity are imposed. We study the cosmological dynamics of the axio-d...

Currently, there is a great deal of interest in the seeking of consistent thermodynamics of the Lorentzian Taub-Newman-Unti-Tamburino (NUT) spacetimes. Despite a lot of “satisfactory” efforts that have been made, all of these activities have been restricted to the four-dimensional cases, with the higher even-dimensional cases remaining unexplored....

Chapter Abstract: Redshift, a fundamental phenomenon in astrophysics and cosmology, is explored in detail through its governing equations. We delve into equations describing redshift as a function of wavelength and frequency changes, energy changes, and phase shifts. These equations provide insights into the behaviour of electromagnetic waves as so...

We present the deep connections among (Anti) de Sitter geometry, and complex conformal gravity-Maxwell theory, stemming directly from a gauge theory of gravity based on the complex Clifford algebra Cl(4, C). This is attained by simply promoting the de (Anti) Sitter algebras so(4, 1), so(3, 2) to the real Clifford algebras Cl(4, 1, R), Cl(3, 2, R),...

Based on the idea of cyclic conformal cosmology, we discuss how torsion may allow for a cosmological constant, which links the ideas given by Beckwith and QaZi 2023 to a presentation as far as Torsion as given by de Sabbata and Sirvaram, Erice 1990. The 1990 article claims that Torsion cancels Cosmological vacuum energy whereas our formulation lead...

Este libro es una apuesta de diálogo intercultural que tiene como propósito visibilizar la relevancia de los movimientos indígenas y contribuir a develar los alcances sociales, jurídicos, ontológicos y epistémicos de sus luchas en América Latina. Se trata de un tejido de diferentes voces, experiencias y reflexiones que permite comprender cómo los m...

In 2007, Witten proposed that the Monster conformal field theory (CFT) is very likely the dual CFT of 3D pure gravity in Anti-de Sitter space. Based on the fact that the Hilbert space of quantum gravity in asymptotically de Sitter space is finite, in this article, an attempt is made to study the de Sitter space dual to the Monster CFT. As the Monst...