Evolution Of Universe Research Articles

Property of Quark-Gluon Plasma

During the nascent stages of the universe's evolution, matter existed in the form of quarkgluon plasma (QGP), characterized by its presence under conditions of exceedingly high temperature andpressure. Presently, the ability to replicate the QGP state has been attained through relativistic heavy.ion collision experiments, Key indicators of QGP generation encompass the initial collision configurationwhich exerts a discernible infuence on the subsequent momentum and scattering angles of emitted hadronsThis study endeavors to recapitulate the findings of the CMS XeXe collision experiment by meticulouslyscrutinizing data stemming from PbPb collisions at a center-of-mass energy of s = 5.02 TeV. Specificallyour focus centers on an exhaustive analysis of the transverse momentum (pt), azimuthal angle (), ancpseudorapidity () of scattered particles. 'Through this comprehensive approach, we aim to corroborate theimplications drawn from the ClMS XeXe experiment, thereby contributing to a deeper understanding of themechanisms underlying quark-gluon plasma creation and behavior

Fractional holographic dark energy

Holographic dark energy theories present a fascinating interface to probe late-time cosmology, as guided by contemporary ideas about quantum gravity. In this work, we present a new holographic dark energy scenario designated “Fractional Holographic Dark Energy” (FHDE). This model extends the conventional framework of HDEs by incorporating specific features from fractional calculus and fractional Wheeler-De Witt equation recently applied, e.g., in cosmological settings. In this manner, we retrieve a novel form of HDE energy density. We then show how FHDE can provide a consistent picture of the evolution of the late-time universe even with the simple choice of the Hubble horizon as the IR (infrared) cutoff. We provide detailed descriptions of the cosmological evolution, showing how the fractional calculus ingredients can alleviate quite a few issues associated with the conventional HDE scenario. Concretely, we compute and plot diagrams using the Hubble horizon cutoff for HDE. The density parameters for DE and dark matter (DM), the deceleration parameter, and the DE EoS parameter indicate how the universe may evolve within our “FHDE” model, fitting within an appropriate scenario of late-time cosmology.

Ensemble Learning for Stellar Classification and Radius Estimation from Multimodal Data

Abstract Stellar classification and radius estimation are crucial for understanding the structure of the universe and stellar evolution. With the advent of the era of astronomical big data, multimodal data are available and theoretically effective for stellar classification and radius estimation. A problem is how to improve the performance of this task by jointly using the multimodal data. However, existing research primarily focuses on using single-modal data. To this end, this paper proposes a model, Multi-Modal SCNet (MMSCNet), and its ensemble model Multimodal Ensemble for Stellar Classification and Regression (MESCR) for improving stellar classification and radius estimation performance by fusing two modality data. In this problem, a typical phenomenon is that the sample numbers of some type stars are evidently more than others. This imbalance has negative effects on model performance. Therefore, this work utilize a weighted sampling strategy to deal with the imbalance issues in MESCR. Some evaluation experiments are conducted on a test set for MESCR and the classification accuracy is 96.1\%, the radius estimation performance Mean of Absolute Error (MAE) and $\sigma$ are 0.084 dex and 0.149 \(R_{\odot}\) respectively. Moreover, we assessed the uncertainty of model predictions, confirming good consistency within a reasonable deviation range. Finally, we applied our model to 50,871,534 SDSS stars without spectra and published a new catalog.

Is the Cyclic Model of the Universe Possible in the Relativistic Theory of Gravitation?

For the flat FLRW model of Universe evolution in RTG a new model of Dark Energy is proposed. It is a global scalar field Φ with the quadratic potential. It ensures cosmological acceleration at the present time and a bounce at the latе times. At the contraction stage Kazner-like growing anisotropy of Riemannian metrics will break a mass-of- the-graviton bounce mechanism near the Big Bang in FLRW case. There is also noncyclic option, when small enough graviton-mass-terms are significant only at the end of expansion. After bounce, during next contraction epoch, an anisotropy grows and the matter density finally reaches the Planck one.

Inflationary Butterfly Effect: Nonperturbative Dynamics from Small-Scale Features.

For the first time, we investigate the nonperturbative dynamics of single field inflation with a departure from slow roll. Using simulations, we find that oscillatory features in the potential can drastically alter the course of inflation, with major phenomenological implications. In certain cases, the entire Universe gets trapped in a forever inflating de Sitter state. In others, only some regions get stuck in a false vacuum, offering an alternative channel for primordial black hole formation. Analogous to the flap of a butterfly, these results show that small-scale phenomena can have profound consequences on the evolution of the entire Universe. More generally, our work shows the power of simulations in the exploration of the small-scale physics of inflation, particularly in the regime relevant for gravitational-wave astronomy.

Dimitrie Cantemir in the face of the change of the civilizational paradigm

In the following communication Dimitrie Cantemir in the face of civilizational paradigm change, the authors try to examine from a different angle the actions of Dimitrie Cantemir (1673-1723) during his short reign in Moldova (1710-1711) and especially regarding his alliance with Peter I, Tsar of Russia (April 2/13, 1711). Starting from the fact that the Romanian scholar during his adolescence and youth had been formed as an intellectual and politician in the Orthodox cultural and spiritual environment from Moldova on the one hand and in that of the Islamic world and culture from Constantinople on the other, it can be assumed that he was acquainted both with the Christian European civilization and with the Arab-Turkish-Persian Oriental one. Throughout his entire literary creation as a historian, philosopher, musician, etc., Cantemir relied on representative scientific, cultural and religious values from both civilizational worlds. As for his political activity, both before and during his reign in Moldova, the Romanian prince understood that his homeland was included in the civilizational area of the Ottoman Empire, a circumstance that inhibited its development and affirmation on the international level. In accordance with the Biblical conception of the universal cycle of the four monarchies, which the erudite prince had embraced and further developed in a special study, Monarchiarum physica examinatio / A Natural Research of Monarchies, he considered that the unfolding political-military events at the crossroads of the two great civilizations, that of Europe and that of Islam, inevitably led to the collapse and disappearance of the Ottoman Empire as a historical anomaly. As a result, the baton of universal evolution would soon be taken over by the Northern monarchy, which was represented, according to D. Cantemir, by the Russian state. This system was used as the theoretical basis for the decision of the prince of Moldavia to break his relations with the Ottoman Gate and negotiate an alliance with the new rising European power. Thus, through such an action in these new circumstances, Cantemir was actually trying to break Moldova away from the area of Oriental civilization and place it de facto as a sovereign country in the new system of European international relations.

On testimony in scenarios with Wigner and Friend

The paper constructs a semi-formal language suited to the analysis of Wigner’s Friend scenarios: it represents an epistemic notion of rational beliefs and perspectives, to accommodate the insights of perspectival interpretations of quantum mechanics. The language is then used to analyze a paradox put forward by Frauchiger and Renner (Nat Commun, 9(1):3711, 2018). Their argument is presented as a semi-formal derivation with specified rules of reasoning. These rules bear an affinity to some of the cherished tenets of epistemology and we argue that they are valid (one universally, and the other in experimental contexts). Since our proof is a reductio, it leaves a choice which premises are responsible for a contradiction. Our first choice is a step that appears incorrect from the point of view of the universal unitary evolution as well as the view that every measurement induces a collapse of a measured system’s state. Our second choice, brought to view by the paper’s attention to perspectives and epistemology, points to a step reporting the transmission of beliefs (testimony) about measurement results. We argue that testimony is not licensed by quantum mechanical formalism; we discuss some recent attempts to save the cogency of testimony in the context of quantum measurements.

Cosmological tests of the dark energy models in Finsler-Randers space-time

The Finsler-Randers space-time offers a novel perspective on cosmic dynamics, departing from the constraints of General Relativity. This paper thoroughly investigates two dark energy models resulting from the parametrization of H within this geometric framework. We have conducted some geometrical and physical analysis of the dark energy models in Finslerian geometry. First, we have derived the field equations governing the universe's evolution within the Finsler-Randers formalism, incorporating the presence of dark energy. Through this, we explore its implications on cosmological phenomena, including cosmic expansion, late-time behavior of the universe, cosmological phase transition, and a few more. Also, we employ observational data such as Cosmic Chronometer, Supernovae, Gamma-Ray Bursts, Quasar, and baryon acoustic oscillations to constrain the parameters associated with dark energy in the Finsler-Randers universe. Comparing theoretical predictions with empirical observations, we assess the model viability and discern any deviations from the standard ΛCDM cosmology. Our findings offer intriguing insights into the nature of dark energy within this alternative gravitational framework, providing a deeper understanding of its role in shaping cosmic evolution. The implications of our results extend to fundamental cosmology, hinting at new avenues for research to unravel the mysteries surrounding dark energy and the geometric structure of the universe within non-standard gravitational theories.

The Ethics of Astrobiology and the Cosmic Bet Argument

Stephen Weinberg posited in 1977 that as the universe becomes more comprehensible, it appears more meaningless owing to a strict division between facts and values. He seemingly overlooked the consideration of the purposes and values of intelligent life in examining its ability to influence the universe's development. The scientific revolution, initiated by Copernicus's heliocentric hypothesis and furthered by Darwin's theory, shifted humanity's perceived place in the cosmos, removing the sacred. However, developments in astrobiology and discoveries related to the Fermi Paradox and the Rare Earth Hypothesis are hinting at humanity's significant role in the universe, suggesting we might be the only intelligent species. This paper argues that advancing scientific knowledge reinforces the hypothesis of human exclusivity and importance in the cosmos, making the potential sixth mass extinction cosmically significant and underscoring the imperative of human persistence in the cosmos.

Modified Gravity in the Presence of Matter Creation: Scenario for the Late Universe.

We consider a dynamic scenario for characterizing the late Universe evolution, aiming to mitigate the Hubble tension. Specifically, we consider a metric f(R) gravity in the Jordan frame which is implemented to the dynamics of a flat isotropic Universe. This cosmological model incorporates a matter creation process, due to the time variation of the cosmological gravitational field. We model particle creation by representing the isotropic Universe (specifically, a given fiducial volume) as an open thermodynamic system. The resulting dynamical model involves four unknowns: the Hubble parameter, the non-minimally coupled scalar field, its potential, and the energy density of the matter component. We impose suitable conditions to derive a closed system for these functions of the redshift. In this model, the vacuum energy density of the present Universe is determined by the scalar field potential, in line with the modified gravity scenario. Hence, we construct a viable model, determining the form of the f(R) theory a posteriori and appropriately constraining the phenomenological parameters of the matter creation process to eliminate tachyon modes. Finally, by analyzing the allowed parameter space, we demonstrate that the Planck evolution of the Hubble parameter can be reconciled with the late Universe dynamics, thus alleviating the Hubble tension.

Dynamical stability and phase space analysis of an emergent Universe with non-interacting and interacting fluids

Abstract We investigate the evolution of a flat Emergent Universe obtained with a non-linear equation of state (nEoS) in Einstein’s general theory of Relativity. The nEoS is equivalent to three different types of barotropic cosmic fluids, which are found from the nEoS parameter. The EU began expanding initially with no interactions among the cosmic fluids. However, one can assume an interaction that sets in at a time t ⩾ t i in the cosmic fluids, we study the evolution of the EU that accommodates the present observed Universe. We adopt dynamical system analysis to study the critical points of the autonomous system and the evolutionary behavior of an EU with or without interaction among the cosmic fluid components. We also study the stability of critical points and plot the phase portraits. The density parameters and the corresponding cosmological parameters are determined for both the non-interacting and interacting phases of the evolutionary dynamics of the Universe.

Confinement and synergy effects of supported-confined bimetal catalysts with superior stability and catalytic activity

Bimetallic nanocrystals have attracted considerable attention because of their complicated systems, which are far superior to those of their individual constituents. A TiO2-confined PtMnP bimetallic catalyst (PtMnP@TiO2) was prepared using an ultrasonic-assisted coincident strategy, which demonstrated exceptional catalytic activity in the universal hydrogen evolution reaction (HER). Owing to the bimetallic synergistic effect and TiO2 confinement, PtMnP@TiOx showed ultrasmall metal nanoparticles (NPs), a higher active Pt0 content, adequate activation at the porous surface, and abundant acid sites. Simulations were performed to visualize the strain properties of Mn and Pt during the bending process and demonstrate the high activity of Pt. The Pt-Mn bimetallic catalysts were enriched with Pt NPs, convoyed by electron transfer from Mn to Pt. Briefly, PtMnP@TiO2 showed robust evolution reaction activities (an overpotential of 220 mV at a current density of 10 mA cm−2 and a Tafel slope of 186 mV dec−1) and the ability to contrast stated catalysts without ultrasonication-plasma. This protocol revealed that the geometrical and electronic effects of Pt and P surrounding the Mn species in PtMnP@TiO2 were crucial for increasing the catalytic activity (99%) and durability (over 20 cycles), which were far superior to those of other reported catalysts.

Jeans instability in the particle-antiparticle system with the different gravitational charges and the ALPHA-g experiment

The principle of binding energy conservation during charge conjugation and the hypothesis of gravitational repulsion of antiparticle masses is used to formulate appropriate two-component hydrodynamics. The dispersion relation for small perturbations is obtained and analyzed. The modified Jeans instability for matter-antimatter system is found as the function of arbitrary fraction of the repulsive matter. For the hydrogen-antihydrogen system, the recent ALPHA-g experimental result is used to apply to the early Universe evolution. It is shown that the non-damping sound mode exists if the annihilation damping is absent.

Automating galaxy morphology classification using k-nearest neighbours and non-parametric statistics

ABSTRACT Morphology is a fundamental property of any galaxy population. It is a major indicator of the physical processes that drive galaxy evolution and in turn the evolution of the entire Universe. Historically, galaxy images were visually classified by trained experts. However, in the era of big data, more efficient techniques are required. In this work, we present a k-nearest neighbours based approach that utilizes non-parametric morphological quantities to classify galaxy morphology in Sloan Digital Sky Survey images. Most previous studies used only a handful of morphological parameters to identify galaxy types. In contrast, we explore 1023 morphological spaces (defined by up to 10 non-parametric statistics) to find the best combination of morphological parameters. Additionally, while most previous studies broadly classified galaxies into early types and late types or ellipticals, spirals, and irregular galaxies, we classify galaxies into 11 morphological types with an average accuracy of ${\sim} 80\!-\!90 \, {{\rm per\, cent}}$ per T-type. Our method is simple, easy to implement, and is robust to varying sizes and compositions of the training and test samples. Preliminary results on the performance of our technique on deeper images from the Hyper Suprime-Cam Subaru Strategic Survey reveal that an extension of our method to modern surveys with better imaging capabilities might be possible.

Cosmology from string T-duality and zero-point length

Inspired by string T-duality and taking into account the zero-point length correction, l0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$l_0$$\\end{document}, to the gravitational potential, we construct modified Friedmann equations by applying the first law of thermodynamics on the apparent horizon of the Friedmann–Robertson–Walker (FRW) Universe. The cosmological viability of this extended scenario is investigated by studying influences on the evolution of the early Universe and performing cosmographic analysis. Furthermore, we explore the inflationary paradigm under the slow-roll condition. By testing the model against observational data, the zero-point length is constrained around the Planck scale, in compliance with the original assumption from string T-duality. We also study the growth of density perturbations in the linear regime. It is shown that the zero-point length stands out as an alternative characterization for the broken-power-law spectrum, providing a better fit for the experimental measurements than the simple power-law potential. Finally, we focus on implications for the primordial gravitational wave (PGW) spectrum. Should the zero-point length be running over energy scales, as is the case for all parameters and coupling constants in quantum gravity under renormalization group considerations, deviations from general relativity (GR) might be potentially tested through upcoming PGW observatories.

О социальной эволюции как части мегаэволюции

The present article is devoted to the issue of the unity of laws, patterns and mechanisms of evolution in all its phases and levels, as well as to the clarification of the aspects of the similarity between social evolution and previous phases in a single process of universal evolution, or megaevolution. Despite the enormous differences between cosmic, planetary, chemical, biological and social forms of evolution, there are many similarities between them. In this article we will consider a number of important similarities which we believe clearly demonstrate the systemic-structural and functional-evolutionary unity of the world at its different levels and in various domains. Understanding of these similarities deepens our perception of social evolution and its patterns and moves us away from the misconception that social evolution is different in all aspects from the evolution of previous levels.

Late time acceleration in Bianchi type-V dark energy cosmological models with linear deceleration parameter

We present a Bianchi type-V cosmological model with deceleration parameter as a simple linear function of the Hubble parameter interacting with a perfect fluid in the general theory of relativity. For Bianchi type-V space-time, the available solutions of Einstein field equations have been procure under the assumption of linear deceleration parameter, q = A + BH, where H is the Hubble parameter. Also,during the evolution of the Bianchi-V universe, dark energy(DE) with a variable EoS parameters has been studied in detail and w slowly varies around w = –0.33 for a 10 GYr. lapse, which involves an accelerated expansion, through an expansion not compatible with current. In this article, we discuss the physical and geometrical facets of the cosmological parameter of the model. Several elements of the model universe are explained by the jerk parameter and energy conditions, including the recent cosmological expansion and singularity theories. We also deliberated state-finder parameters, which forecast that the Universe created from Einstein’s static era rallies towards ΛCDM model (r = 1, s = 0).

Analysis of the Composition and Characteristics of Dark Matter

Today, astronomers use different methods to study the structure and evolution of the universe. However, they will all be affected by other factors such as light or electromagnetic radiation. It is impossible to accurately observe the structure of the universe in the distant past. To find objects that fit the criteria, the existence of dark matter was assumed. It only has a gravitational effect and will be less affected. The composition and characteristics of dark matter are important research foundations. In this paper, the Cosmic Microwave Background (CMB) and power spectrum are used to study the status of dark matter in the universe. The search found Weakly Interacting Massive Particles (WIMPs) to be a candidate in the dark matter component. The three types of dark matter are cold dark matter, warm dark matter, and hot dark matter. Comparing their respective characteristics, it is concluded that cold dark matter (CDM) is the condition for observing large-scale structures. The result is that dark matter constitutes the second largest component of the universe. WIMPs are more suitable candidates than Neutrinos. CDM is best suited for studying large-scale structures over time. Eventually, it will be discovered that dark matter has strong stability, which will help astronomers find the process of universe evolution. Dark matter is also an important player that is best used to study the structure and evolution of the universe.

Cosmological evolution of new Tsallis agegraphic dark energy with conformal time as IR-cutoff

This paper considers the only sectors to constitute the present universe as the dark matter and dark energy. The proposed new agegraphic dark energy model studies the gradual transition from matter to dark energy in sequential order, including the current dominance of the matter sector by dark energy. The model utilizes concepts of Tsallis entropy and the Karolyhazy relation with conformal time [Formula: see text] as the time scale. Various evolutionary aspects of the universe are characterized by Tsallis parameter [Formula: see text] and the model constant [Formula: see text]. Expressions for dynamic behavior of dark energy, as a differential equation, equation of state and deceleration parameters are obtained to describe the thermal history of universe evolution. Also, the stability of the model is analyzed through squared sound speed parameter. The analysis is made by considering an interaction as well as independence among the constituent sectors of the universe.

Statistical Anisotropy of Primordial Gravitational Waves from Generalized δN Formalism.

In this Letter, we demonstrate how to use the generalized δN formalism, which enables us to compute the evolution of all the large-scale fluctuations, including gravitational waves, solely by solving the evolution of the background homogeneous Universe. Using the Noether charge density, we derive an analytic formula which describes the mapping between the fluctuations at the horizon crossing and the sourced gravitational waves at the end of inflation. This formula can apply also to an inflation model with an anisotropic background. Using this formula, we discuss the condition for the nonvanishing linear polarization and the qualitative difference between single- and multigauge field models.