Implications of a class of grand unified theories for large scale structure in the universe

A class of grand unified theories in which cosmologicaly significant axion and neutrino energy densities arise naturally is discussed. To obtain large scale structure three scenarios are considered: (1) an inflationary scenario; (2) inflation followed by string production; and (3) a non-inflationary scenario with density fluctuations caused solely by strings. Inflation may be compatible with the recent observational indications that mega 1 on the scale of superclusters, particularly if strings are present

The evolution of structure in the universe from axions

A scenario where axions provide the dark matter in the universe is considered. Fluctuations in the axion field density produced by domain walls and strings cause the appearance of axion clumps of masses of order 10 to the 6th power solar mass which most likely collapse to black holes by or at the time that the universe becomes axion dominated at T is approximately 10 eV. These objects form the building blocks for a clustering hierarchy theory of galaxy and supercluster formation on scales up to approximately 10 Mpc and approximately 10 to the 15th power solar mass

Spontaneous Breaking of Lepton Number and Cosmological Domain Wall Problem

We show that if global lepton number symmetry is spontaneously broken in a post inflation epoch, then it can lead to the formation of cosmological domain walls. This happens in the well-known "Majoron paradigm" for neutrino mass generation. We propose some realistic examples which allow spontaneous lepton number breaking to be safe from such domain walls.Comment: 8 pages, References added, Discussion on Domain Wall Problem Expanded, Conclusions Unchanged, Version Published in Phys. Rev. Let

Structure of vasa deferentia and spermatophores in Parapenaeopsis stylifera (H. Milne Edwards) (Decapoda: Penaeidae)

The structure of vasa deferentia and spermatophores has been described in Parapenaeopsis stylifera. The male reproductive system consists of two symmetrical halves; each half bears testis, vas deferens and an ejaculatory duct. Each testis comprised of two to three short, broad and milky white lobes; vas deferens is divisible into proximal, medial and distal parts. The proximal vas deferens (PVD) is a convoluted mass made up of an extremely long and thin tube having elongated rod like spermatozoa. The median vas deferens (MVD) is broad, straight, somewhat flattened and bears many membranous folds internally and contained complete spermatophores; the distal vas deferens (DVD) is straight and cylindrical tube. The ejaculatory duct is a simple dilation with a tubular basal part tapered posteriorly for extrusion of spermatophores. The spermatophores are minute, spindle shaped bodies present in large numbers in each ejaculatory duct; the size varied from 0.148 to 0.161 mm; each spermatophore bears six to eight rows of regularly arranged spermatozoa. Histological studies reveal no internal partitioning of either vas deferens or ejaculatory duct.Keywords: Parapenaeopsis stylifer, vasa deferentia, spermatophore

Some Properties of Domain Wall Solution in the Randall-Sundrum Model

Properties of the domain wall (kink) solution in the 5 dimensional Randall-Sundrum model are examined both {\it analytically} and {\it numerically}. The configuration is derived by the bulk Higgs mechanism. We focus on 1) the convergence property of the solution, 2) the stableness of the solution, 3) the non-singular property of the Riemann curvature, 4) the behaviours of the warp factor and the Higgs field. It is found that the bulk curvature changes the sign around the surface of the wall. We also present some {\it exact} solutions for two simple cases: a) the no potential case, b) the cosmological term dominated case. Both solutions have the (naked) curvature singularity. We can regard the domain wall solution as a singularity resolution of the exact solutions.Comment: Typographical error correction for publication. 16 pages, 4 figure

Neutrino Democracy, Fermion Mass Hierarchies And Proton Decay From 5D SU(5)

The explanation of various observed phenomena such as large angle neutrino oscillations, hierarchies of charged fermion masses and CKM mixings, and apparent baryon number conservation may have a common origin. We show how this could occur in 5D SUSY SU(5) supplemented by a ${\cal U}(1)$ flavor symmetry and additional matter supermultiplets called 'copies'. In addition, the proton decays into $p\to K\nu$, with an estimated lifetime of order $10^{33}-10^{36}$ yrs. Other decay channels include $Ke$ and $K\mu$ with comparable rates. We also expect that BR$(\mu \to e\gamma)\sim$BR$(\tau \to \mu \gamma)$

Tensor to Scalar Ratio in Non-Minimal ϕ4\phi^4 Inflation

We reconsider non-minimal \lambda \phi^4 chaotic inflation which includes the gravitational coupling term \xi \mathcal{R} \phi^2, where \phi denotes a gauge singlet inflaton field and \mathcal{R} is the Ricci scalar. For \xi >> 1 we require, following recent discussions, that the energy scale \lambda^{1/4} m_P / \sqrt{\xi} for inflation should not exceed the effective UV cut-off scale m_P / \xi, where m_P denotes the reduced Planck scale. The predictions for the tensor to scalar ratio r and the scalar spectral index n_s are found to lie within the WMAP 1-\sigma bounds for 10^{-12} < \lambda < 10^{-4} and 10^{-3} < \xi < 10^2. In contrast, the corresponding predictions of minimal \lambda \phi^4 chaotic inflation lie outside the WMAP 2-\sigma bounds. We also find that r > 0.002, provided the scalar spectral index n_s > 0.96. In estimating the lower bound on r we take into account possible modifications due to quantum corrections of the tree level inflationary potential.Comment: 10 pages, 6 figure

A Theory of Unsupervised Translation Motivated by Understanding Animal Communication

Recent years have seen breakthroughs in neural language models that capture nuances of language, culture, and knowledge. Neural networks are capable of translating between languages -- in some cases even between two languages where there is little or no access to parallel translations, in what is known as Unsupervised Machine Translation (UMT). Given this progress, it is intriguing to ask whether machine learning tools can ultimately enable understanding animal communication, particularly that of highly intelligent animals. Our work is motivated by an ambitious interdisciplinary initiative, Project CETI, which is collecting a large corpus of sperm whale communications for machine analysis. We propose a theoretical framework for analyzing UMT when no parallel data are available and when it cannot be assumed that the source and target corpora address related subject domains or posses similar linguistic structure. The framework requires access to a prior probability distribution that should assign non-zero probability to possible translations. We instantiate our framework with two models of language. Our analysis suggests that accuracy of translation depends on the complexity of the source language and the amount of ``common ground'' between the source language and target prior. We also prove upper bounds on the amount of data required from the source language in the unsupervised setting as a function of the amount of data required in a hypothetical supervised setting. Surprisingly, our bounds suggest that the amount of source data required for unsupervised translation is comparable to the supervised setting. For one of the language models which we analyze we also prove a nearly matching lower bound. Our analysis is purely information-theoretic and as such can inform how much source data needs to be collected, but does not yield a computationally efficient procedure