Universe Cosmology Research Articles

Phase transitions in anisotropic multidimensional systems

A new class of models, which might be used to describe the phase transitions in anisotropic multidimensional systems with both higher-order spatial order parameter (OP) derivatives and higher OP nonlinearities, is proposed. Such models may be useful in the study of phase transitions in early universe cosmology; inflation cosmology; superstring, p-branes and other non-point objects theories. Both the upper and the lower critical dimensions of the models were calculated. It allows one to define the ranges of the mean-field theory applicability for describing critical phenomena in the proposed models.

Data-Driven Insights to Cosmology in the Dark Universe

The research provides a qualitative analysis with data-driven evidence on the dark energy and dark universe in cosmology and large-scale structure. It provides a descriptive account of the causal significance of black hole and white hole thermonuclear binding to instrumental observational schemes. The article adopted a postpositive paradigm in reorganizing from the previous experimental procedures and finer details not previously covered. The qualitative research into the dark universe has not yet reached a quantifiable stage but may contribute to the data-driven and informatics approaches to the supplement of the simulation methods that underly the services for observation coordination. The research proposes that the change in Shannon Entropy with regard to fundamental asymmetry and CP violation may contribute to data-driven insights into the cosmological large-scale structure, with an electrolyte and hydrolysis approach to quantum superconductive information.

The Scientific Spirit of American Humanism

The Scientific Spirit of American Humanism

Exact fermionic Chern-Simons-Kodama state in quantum gravity

The Chern-Simons-Kodama (CSK) state is an exact, non-perturbative wave function in the Ashtekar formulation of classical General Relativity. In this work, we find a generalized fermionic CSK state by solving the extended gravitational and fermionic Hamiltonian constraints of the Wheeler-DeWitt equation exactly. We show that this new state reduces to the original Kodama state upon symmetry reduction to FRW coordinates with perturbative fermionic corrections, making contact with the Hartle-Hawking and Vilenkin wave functions of the universe in cosmology. We also find that when both torsion and fermions are non-vanishing, the wave function possesses a finite amplitude to evade the Big Bang curvature singularity.

Precision early universe cosmology from stochastic gravitational waves

The causal tail of stochastic gravitational waves can be used to probe the energy density in free streaming relativistic species as well as measure g*(T) and beta functions β(T) as a function of temperature. In the event of the discovery of loud stochastic gravitational waves, we demonstrate that LISA can measure the free streaming fraction of the universe down to the the 10−3 level, 100 times more sensitive than current constraints. Additionally, it would be sensitive to mathcal{O} (1) deviations of g* and the QCD β function from their Standard Model value at temperatures ~ 105 GeV. In this case, many motivated models such as split SUSY and other solutions to the Electroweak Hierarchy problem would be tested. Future detectors, such as DECIGO, would be 100 times more sensitive than LISA to these effects and be capable of testing other motivated scenarios such as WIMPs and axions. The amazing prospect of using precision gravitational wave measurements to test such well motivated theories provides a benchmark to aim for when developing a precise understanding of the gravitational wave spectrum both experimentally and theoretically.

CRITICAL PHENOMENA IN ANISOTROPIC MULTIDIMENSIONAL SYSTEMS

A class of models, which describe the critical phenomena in anisotropic multidimensional systems with both higher-order spatial order parameter (OP) derivatives and higher OP nonlinearities is proposed. Such models may be useful in the study of phase transitions in early universe cosmology; inflation cosmology; superstring, p-branes and other non-point objects theories. Both the upper and the lower critical dimensions of the models were calculated. It allows one to define the ranges of the mean-field theory applicability for describing critical phenomena in the proposed models.

The inflaton that could: primordial black holes and second order gravitational waves from tachyonic instability induced in Higgs-R 2 inflation

The running of the Higgs self coupling may lead to numerous phenomena in early universe cosmology. In this paper we introduce a scenario where the Higgs running induces turns in the trajectory passing a region with tachyonic mass, leading to a temporal tachyonic growth in the curvature power spectrum. This effect induced by the Higgs leaves phenomena in the form of primordial black holes and stochastic gravitational waves, where proposed GW observatories will be able to probe in the near future.

Higgstory repeats itself

We consider a scalar potential with two minima, one of which is arbitrarily deep, such as could be the case for the Higgs potential in the Standard Model. A recent calculation within the thin-wall approximation [1] concludes that regions in which the scalar field takes values beyond the top of the potential barrier are forced by gravity to collapse, while they remain hidden behind a black hole horizon. We show that the thin-wall approximation is not applicable to this problem. We clarify the issue through numerical and analytical solutions to the field equations of the gravity-scalar system. We find that regions around the deeper minimum expand, and would thereby engulf the Universe in post-inflationary cosmology. We also show that black holes with Higgs hair are unstable. Even though the physics of the true vacuum is different, our final conclusion replicates the earlier ‘Higgstory’ paper [2].

Emergent metric space-time from matrix theory

The IKKT matrix model yields an emergent space-time. We further develop these ideas and give a proposal for an emergent metric. Based on previous numerical studies of this model, we provide evidence that the emergent space-time is continuous and infinite in extent, both in space and in time, and that the metric is spatially flat. The time evolution describes the transition from a string-theoretic emergent phase to a phase in which the SO(9) symmetry of the model is spontaneously broken to SO(6) × SO(3), with three dimensions of space expanding, becoming classical and at later times evolving like in a radiation-dominated universe, and the remaining six dimensions of space stabilized at the string scale. We speculate on how this analysis can be extended to yield an early universe cosmology which, in addition to the above-mentioned properties, also leads to a roughly scale-invariant spectrum of cosmological fluctuations and gravitational waves.

Cosmological dependence of sterile neutrino dark matter with self-interacting neutrinos

Unexplored interactions of neutrinos could be the key to understanding the nature of the dark matter (DM). In particular, active neutrinos with new self-interactions can produce keV-mass sterile neutrinos that account for the whole of the DM through the Dodelson-Widrow mechanism for a large range of active-sterile mixing values. This production typically occurs before Big-Bang Nucleosynthesis (BBN) in a yet uncharted era of the Universe. We assess how the mixing range for keV-mass sterile neutrino DM is affected by the uncertainty in the early Universe pre-BBN cosmology.This is particularly relevant for identifying the viable parameter space of sterile neutrino searches allowed by all astrophysical limits, as well as for cosmology, since the detection of a sterile neutrino could constitute the first observation of a particle providing information about the pre-BBN epoch. We find that the combined uncertainties in the early Universe cosmology and neutrino interactions significantly expand the allowed parameter space for sterile neutrinos that can constitute the whole of the DM.

Universe Radius-Electron Relationship Shows Electron Creation is the Dark Energy Driving Quantized Universe Expansion

IJCAA publishes original hypotheses and discoveries in cosmology, astronomy, space science and technology, astrophysics, astrobiology, plasma physics, and Earth & planetary sciences. It covers multiple disciplines and sub-disciplines of biology, geology, physics, chemistry, extinction, the origin and evolution of life and Martian colonization and exploration. It mainly focuses on the conceptual problems of the current paradigm of early universe cosmology and astronomy, thus motivating exploration of the potential of string theory to provide a new paradigm.

Emergent early universe cosmology from BFSS matrix theory

The BFSS matrix model is a suggested nonperturbative definition of string theory. Starting from a thermal state of this matrix model, we show how space and time can emerge dynamically. Results from the IKKT matrix model indicate that the SO(9) symmetry of space is spontaneously broken to SO(3) × SO(6), with the three-dimensional subspace becoming large. Given this initial state for the universe, we show that cosmological perturbations and gravitational waves with scale-invariant spectra are generated, without the need of postulating an early phase of cosmological inflation. The Big Bang singularity is automatically resolved.

Searching for dark radiation at the LHC

In this work we explore the intriguing connections between searches for long-lived particles (LLPs) at the LHC and early universe cosmology. We study the non-thermal production of ultra-relativistic particles (i.e. dark radiation) in the early universe via the decay of weak-scale LLPs and show that the cosmologically interesting range ∆Neff ~ 0.01–0.1 corresponds to LLP decay lengths in the mm to cm range. These decay lengths lie at the boundary between prompt and displaced signatures at the LHC and can be comprehensively explored by combining searches for both. To illustrate this point, we consider a scenario where the LLP decays into a charged lepton and a (nearly) massless invisible particle. By reinterpreting searches for promptly decaying sleptons and for displaced leptons at both ATLAS and CMS we can then directly compare LHC exclusions with cosmological observables. We find that the CMB-S4 target value of ∆Neff = 0.06 is already excluded by current LHC searches and even smaller values can be probed for LLP masses at the electroweak scale.

Satisfiable Cosmologies

IJCAA publishes original hypotheses and discoveries in cosmology, astronomy, space science and technology, astrophysics, astrobiology, plasma physics, and Earth & planetary sciences. It covers multiple disciplines and sub-disciplines of biology, geology, physics, chemistry, extinction, the origin and evolution of life and Martian colonization and exploration. It mainly focuses on the conceptual problems of the current paradigm of early universe cosmology and astronomy, thus motivating exploration of the potential of string theory to provide a new paradigm.

Northern Hemisphere UHECR data further supports CMBR photons with weak U(1) component

I further test the theory that the Cosmic Background Radiation (CBR) is made of photons with a weak U(1) component. Tipler (2005) has previously argued that the consistency of the Standard Model (SM) with the Second Law of Thermodynamics requires the early universe CBR to be composed mainly of an SU(2) gauge field. The U(1) field would be suppressed. One of the consequences of this approach is that the Ultra High Energy Cosmic Rays (UHECR) would be able to propagate much further than conventionally accepted, as an SU(2) dominant CBR would be largely unable to couple with right handed fermions. I test if this novel theory solves the problem of UHECR origin by finding suitable candidates up to a redshift z = 0.1 within three degrees of the arrival direction. Utilizing the Fly's Eye Northern Hemisphere UHECR data, I identified candidates with 80% success for the Northern Sky UHECR (98.7% if certain celestial objects which are likely to be Active Galactic Nuclei are absolutely identified as such). This is parsimonious with the CBR theory, which has other important implications for the Standard Model, early universe cosmology, and the origin of matter and anti-matter. This builds off of Tipler and Piasecki (2018), where we have reviewed UHECR data from the Southern Hemisphere to get a 86% success identification rate. We predict that the remaining UHECR not paired with a potential source will have sources identified upon closer telescopic investigations of these regions. Other recent experiments further suggest an SU(2) dominant composition of the CBR photons. The problem of UHECR origin may be solved.

Gravitational dark matter: Free streaming and phase space distribution

Gravitational dark matter (DM) is the simplest possible scenario that has recently gained interest in the early Universe cosmology. In this scenario, DM is assumed to be produced from the scattering of inflatons through the gravitational interaction during reheating. Gravitational production from the radiation bath will be ignored as our analysis shows it to be suppressed for a wide range of reheating temperatures $({T}_{\mathrm{re}})$. Ignoring any other internal parameters except the DM mass $({m}_{Y})$ and spin, a particular inflation model such as $\ensuremath{\alpha}$ attractor, with a specific scalar spectral index $({n}_{s})$ has been shown to uniquely fix the DM mass of the present Universe. For fermion type DM, we found the mass ${m}_{f}$ should be within $({10}^{4}--{10}^{13})\text{ }\text{ }\mathrm{GeV}$, and for boson/vector type DM, the mass ${m}_{s}/{m}_{X}$ turned out to be within $(1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}/9.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}--{10}^{13})\text{ }\text{ }\mathrm{GeV}$. Interestingly, if the inflaton equation of state ${\ensuremath{\omega}}_{\ensuremath{\phi}}\ensuremath{\rightarrow}1/3$, the DM mass also approaches towards unique value, ${m}_{f}\ensuremath{\sim}{10}^{10}\text{ }\text{ }\mathrm{GeV}$ and ${m}_{s}({m}_{X})\ensuremath{\sim}{10}^{3}(8\ifmmode\times\else\texttimes\fi{}{10}^{3})\text{ }\text{ }\mathrm{GeV}$. We further analyzed the phase space distribution ${f}_{Y}$ and free streaming length ${\ensuremath{\lambda}}_{\mathrm{fs}}$ of these gravitationally produced DM. ${f}_{Y}$, which is believed to encode important information about DM, contains a characteristic primary peak at the initial time where the gravitational production is maximum for both fermionic and bosonic DM. Apart from this fermionic phase space, the distribution function contains an additional peak near the inflaton and fermion mass equality (${m}_{Y}\ensuremath{\sim}{m}_{\ensuremath{\phi}}$) arising for ${\ensuremath{\omega}}_{\ensuremath{\phi}}>5/9$. Furthermore, the height of this additional peak turned out to be increasing with decreasing ${T}_{\mathrm{re}}$ and at some point, dominates over the primary one. Since reheating is a causal process and DM is produced during this phase, gravitational instability forming small-scale DM structures during this period will encode those phase space information and be observed at present. The crucial condition of forming such a small-scale DM structure during reheating suggests that the ${\ensuremath{\lambda}}_{\mathrm{fs}}$ must be less than the length scale associated with the mode reentering the Hubble radius at the end of reheating ${\ensuremath{\lambda}}_{\mathrm{re}}$, which has been analyzed in detail. We further estimate in detail the range of scales within which the above condition will be satisfied for different masses of scalar, fermionic, and vector DM. Finally, we end by stating the fact that all our results are observed to be insensitive on the parameter $\ensuremath{\alpha}$ of the inflaton potential within the allowed range set by the latest Planck and BICEP/Keck results.

Limitations of an effective field theory treatment of early Universe cosmology.

Assuming that superstring theory is the fundamental theory which unifies all forces of Nature at the quantum level, I argue that there are key limitations to the applicability of effective field theory techniques in describing early Universe cosmology. This article is part of the theme issue 'The future of mathematical cosmology, Volume 2'.

Viewing the World through Cosmovision at Late Preclassic Noh K'uh in Chiapas, Mexico

This article examines how landscape modification was key to the development of an urbanizing society within a valley in Chiapas, Mexico. The Late Preclassic (400 bc–ad 250) site of Noh K'uh demonstrates how both the altered and unaltered environment signified the importance of cosmological concepts within this society. In an area rich with mountains and caves, the natural landscape offered residents opportunities to create symbolically meaningful living spaces. Evidence from local settlements reveals how the cosmological universe played a guiding role during the site's peak growth period, suggesting that other common contributors (such as economic and militaristic needs) of expansion may have been secondary.

Early and late universe holographic cosmology from a new generalized entropy

We propose a new four-parameter entropy function that generalizes the Tsallis, Rényi, Barrow, Sharma-Mittal, Kaniadakis and Loop Quantum Gravity entropies for suitable limits of the parameters. Consequently, we address the early and late universe cosmology corresponding to the proposed four-parameter entropy function. As a result, it turns out that the entropic cosmology from the generalized entropy function can unify the early inflation to the late dark energy era of the universe. In such a unified scenario, we find that – (1) the inflation era is described by a quasi de-Sitter evolution of the Hubble parameter, which has an exit at around 58 e-folding number, (2) the inflationary observable quantities like the spectral index for primordial scalar perturbation and the tensor-to-scalar ratio are simultaneously compatible with the recent Planck data, and (3) regarding the late time cosmology, the dark energy EoS parameter is found to be consistent with the Planck result for the same values of the entropy parameters that lead to the viable inflation during the early universe. Furthermore, we show that the entropic cosmology from the proposed entropy function is equivalent to holographic cosmology, where the respective holographic cut-offs are determined in terms of either particle horizon and its derivative or future horizon and its derivative.

Soap Bubbles on the Surface of a Liquid: A Playful Universe in 3+1 Dimensions, a Real Universe in 4+1 Dimensions

IJCAA publishes original hypotheses and discoveries in cosmology, astronomy, space science and technology, astrophysics, astrobiology, plasma physics, and Earth & planetary sciences. It covers multiple disciplines and sub-disciplines of biology, geology, physics, chemistry, extinction, the origin and evolution of life and Martian colonization and exploration. It mainly focuses on the conceptual problems of the current paradigm of early universe cosmology and astronomy, thus motivating exploration of the potential of string theory to provide a new paradigm.