scholarly journals COSMOLOGICAL SOLUTION IN M-THEORY ON S1/Z2

1999 ◽  
Vol 08 (02) ◽  
pp. 153-160 ◽  
Author(s):  
KARIM BENAKLI
Keyword(s):  
Cosmological Solution ◽  
Radial Coordinate ◽  
Expanding Universe ◽  
Instanton Solution ◽  
Tunneling Process ◽  
Yang Mills ◽  
Lorentzian Signature ◽  
M Theory ◽  
The Universe

We provide the first example of a cosmological solution of the Horava–Witten supergravity. This solution is obtained by exchanging the role of time with the radial coordinate of the transverse space to the five-brane soliton. On the boundary, this corresponds to rotating an instanton solution into a tunneling process in a space with Lorentzian signature, leading to an expanding universe. Due to the freedom to choose different nontrivial Yang–Mills backgrounds on the boundaries, the two walls of the universe (visible and hidden worlds) expand differently. However at late times the anisotropy is washed away by gravitational interactions.

scholarly journals Gravitational Radiation as the Bremsstrahlung of Superheavy Particles in the Early Universe

Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 188
Author(s):  
Andrey A. Grib ◽  
Yuri V. Pavlov
Keyword(s):  
Early Universe ◽  
Gravitational Radiation ◽  
Background Radiation ◽  
Particle Creation ◽  
Grand Unification ◽  
Expanding Universe ◽  
The Universe

The number of superheavy particles with the mass of the Grand Unification scale with trans-Planckian energy created at the epoch of superheavy particle creation from the vacuum by the gravitation of the expanding Universe is calculated. In later collisions of these particles, gravitational radiation is radiated playing the role of bremsstrahlung for gravity. The effective background radiation of the Universe is evaluated.

scholarly journals The Expansion of the Universe

2020 ◽  
Vol 8 (07) ◽  
pp. 25-31
Author(s):  
Dr. Andreas Gimsa
Keyword(s):  
Background Radiation ◽  
Expanding Universe ◽  
Stellar Radiation ◽  
Expansion Of The Universe ◽  
Accelerated Growth ◽  
The Universe ◽  
Physical Quantities

The expansion of the universe is explained, calculated and graphically displayed. The 3K background radiation is examined and interpreted as reflected and distributed stellar radiation. The role of entropy in cosmology is discussed. In our expanding universe it must remain constant. Physical quantities previously assumed to be constant are worked out to be variable. It is explained why the measured redshift is not due to an accelerated growth of the universe.

scholarly journals Dynamics and Clusters of Galaxies

1974 ◽  
Vol 62 ◽  
pp. 273-284
Author(s):  
D. G. Saari
Keyword(s):  
Virial Theorem ◽  
Gravitational Force ◽  
Clusters Of Galaxies ◽  
Expanding Universe ◽  
Evolution Of The Universe ◽  
Mathematical Probability ◽  
The Masses ◽  
The Universe

Under the assumption that the inverse square central force law is a good approximation to the gravitational force, at least for large distances, the different possibilities for the evolution of the Universe are sketched. Several of the possibilities lead naturally to a dynamical classification of clusters of galaxies in an expanding universe. In one of the classifications the galaxies must define configurations which are functions of the masses. The virial theorem approach of determining masses of galaxies in a cluster is briefly examined. Some tentative statements concerning a dynamical explanation of the local hypothesis for quasars are advanced. Finally, the role of mathematical probability in predicting the behavior of the Universe is discussed.

Quantitative Conditions and Convergent Operations That Are Compatible With the Universe as a Persistent Generator of Successive Simulations

2016 ◽  
Vol 12 (1) ◽  
pp. 4178-4187
Author(s):  
Michael A Persinger ◽  
Stanley A Koren
Keyword(s):  
Structural Organization ◽  
Total Duration ◽  
Human Cognition ◽  
Intrinsic Properties ◽  
Basic Assumptions ◽  
Electron Orbit ◽  
Quantitative Analyses ◽  
Massive Information ◽  
The Universe

                The capacity for computer-like simulations to be generated by massive information processing from electron-spin potentials supports Bostrom’s hypothesis that matter and human cognition might reflect simulations. Quantitative analyses of the basic assumptions indicate the universe may display properties of a simulation where photons behave as pixels and gravitons control the structural organization. The Lorentz solution for the square of the light and entanglement velocities converges with the duration of a single electron orbit that ultimately defines properties of matter. The approximately one trillion potential states within the same space with respect to the final epoch of the universe indicate that a different simulation, each with intrinsic properties, has been and will be generated as a type of tractrix defined by ±2 to 3 days (total duration 5 to 6 days). It may define the causal limits within a simulation. Because of the intrinsic role of photons as the pixel unit, phenomena within which flux densities are enhanced, such as human cognition (particularly dreaming) and the cerebral regions associated with those functions, create the conditions for entanglement or excess correlations between contiguous simulations. The consistent quantitative convergence of operations indicates potential validity for this approach. The emergent solutions offer alternative explanations for the limits of predictions for multivariate phenomena that could be coupled to more distal simulations.

Laws of Nature

2018 ◽  
Keyword(s):  
Philosophy Of Science ◽  
Laws Of Nature ◽  
Current Debate ◽  
Scientific Theories ◽  
Law Of Nature ◽  
First Time ◽  
The Universe

The concept of a law of nature, while familiar, is deeply puzzling. Theorists such as Descartes think a divine being governs the universe according to the laws which follow from that being’s own nature. Newton detaches the concept from theology and is agnostic about the ontology underlying the laws of nature. Some later philosophers treat laws as summaries of events or tools for understanding and explanation, or identify the laws with principles and equations fundamental to scientific theories. In the first part of this volume, essays from leading historians of philosophy identify central questions: are laws independent of the things they govern, or do they emanate from the powers of bodies? Are the laws responsible for the patterns we see in nature, or should they be collapsed into those patterns? In the second part, contributors at the forefront of current debate evaluate the role of laws in contemporary Best System, perspectival, Kantian, and powers- or mechanisms-based approaches. These essays take up pressing questions about whether the laws of nature can be consistent with contingency, whether laws are based on the invariants of scientific theories, and how to deal with exceptions to laws. These twelve essays, published here for the first time, will be required reading for anyone interested in metaphysics, philosophy of science, and the histories of these disciplines.

scholarly journals Dust Production around Carbon-Rich Stars: The Role of Metallicity

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 233
Author(s):  
Ambra Nanni ◽  
Sergio Cristallo ◽  
Jacco Th. van Loon ◽  
Martin A. T. Groenewegen
Keyword(s):  
Wind Speed ◽  
Galactic Halo ◽  
Magellanic Clouds ◽  
Asymptotic Giant Branch ◽  
Agb Stars ◽  
Circumstellar Envelopes ◽  
Chemical Enrichment ◽  
Wide Range ◽  
The Universe

Background: Most of the stars in the Universe will end their evolution by losing their envelope during the thermally pulsing asymptotic giant branch (TP-AGB) phase, enriching the interstellar medium of galaxies with heavy elements, partially condensed into dust grains formed in their extended circumstellar envelopes. Among these stars, carbon-rich TP-AGB stars (C-stars) are particularly relevant for the chemical enrichment of galaxies. We here investigated the role of the metallicity in the dust formation process from a theoretical viewpoint. Methods: We coupled an up-to-date description of dust growth and dust-driven wind, which included the time-averaged effect of shocks, with FRUITY stellar evolutionary tracks. We compared our predictions with observations of C-stars in our Galaxy, in the Magellanic Clouds (LMC and SMC) and in the Galactic Halo, characterised by metallicity between solar and 1/10 of solar. Results: Our models explained the variation of the gas and dust content around C-stars derived from the IRS Spitzer spectra. The wind speed of the C-stars at varying metallicity was well reproduced by our description. We predicted the wind speed at metallicity down to 1/10 of solar in a wide range of mass-loss rates.

scholarly journals Celestial superamplitude in $$ \mathcal{N} $$ = 4 SYM theory

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Hongliang Jiang
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Scattering Amplitudes ◽  
Momentum Space ◽  
Ward Identity ◽  
Yang Mills ◽  
Conformal Field ◽  
New Perspective ◽  
Celestial Sphere

Abstract Celestial amplitude is a new reformulation of momentum space scattering amplitudes and offers a promising way for flat holography. In this paper, we study the celestial amplitudes in $$ \mathcal{N} $$ N = 4 Super-Yang-Mills (SYM) theory aiming at understanding the role of superconformal symmetry in celestial holography. We first construct the superconformal generators acting on the celestial superfield which assembles all the on-shell fields in the multiplet together in terms of celestial variables and Grassmann parameters. These generators satisfy the superconformal algebra of $$ \mathcal{N} $$ N = 4 SYM theory. We also compute the three-point and four-point celestial super-amplitudes explicitly. They can be identified as the conformal correlation functions of the celestial superfields living at the celestial sphere. We further study the soft and collinear limits which give rise to the super-Ward identity and super-OPE on the celestial sphere, respectively. Our results initiate a new perspective of understanding the well-studied $$ \mathcal{N} $$ N = 4 SYM amplitudes via 2D celestial conformal field theory.

scholarly journals Local G2-manifolds, Higgs bundles and a colored quantum mechanics

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Max Hübner
Keyword(s):  
Quantum Mechanics ◽  
Gauge Theories ◽  
Supersymmetric Quantum Mechanics ◽  
Higgs Bundle ◽  
Higgs Bundles ◽  
View Point ◽  
Yang Mills ◽  
G2 Manifolds ◽  
Supersymmetric Gauge ◽  
M Theory

Abstract M-theory on local G2-manifolds engineers 4d minimally supersymmetric gauge theories. We consider ALE-fibered G2-manifolds and study the 4d physics from the view point of a partially twisted 7d supersymmetric Yang-Mills theory and its Higgs bundle. Euclidean M2-brane instantons descend to non-perturbative effects of the 7d supersymmetric Yang-Mills theory, which are found to be in one to one correspondence with the instantons of a colored supersymmetric quantum mechanics. We compute the contributions of M2-brane instantons to the 4d superpotential in the effective 7d description via localization in the colored quantum mechanics. Further we consider non-split Higgs bundles and analyze their 4d spectrum.

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