Projective relativity, cosmology and gravitation
International Nuclear Information System (INIS)
Arcidiacono, G.
1986-01-01
This book describes the latest applications of projective geometry to cosmology and gravitation. The contents of the book are; the Poincare group and Special Relativity, the thermodynamics and electromagnetism, general relativity, gravitation and cosmology, group theory and models of universe, the special projective relativity, the Fantappie group and Big-Bang cosmology, a new cosmological projective mechanics, the plasma physics and cosmology, the projective magnetohydrodynamics field, projective relativity and waves propagation, the generalizations of the gravitational field, the general projective relativity, the projective gravitational field, the De Sitter Universe and quantum physics, the conformal relativity and Newton gravitation
, i.e. with the cosmology hidden. Looking Beyond Lambda with the Union Supernova Compilation by Rubin et Matrix Description Covariance Matrix with Systematics Description Full Table of All SNe Description Beyond Lambda Figures Updated 11-18-11 Contact: drubin at physics dot fsu dot edu, saul at lbl dot gov
Chandra Cluster Cosmology Project. II. Samples and X-Ray Data Reduction
DEFF Research Database (Denmark)
Vikhlinin, A.; Burenin, R. A.; Ebeling, H.
2009-01-01
We discuss the measurements of the galaxy cluster mass functions at z ≈ 0.05 and z ≈ 0.5 using high-quality Chandra observations of samples derived from the ROSAT PSPC All-Sky and 400 deg2 surveys. We provide a full reference for the data analysis procedures, present updated calibration of relati...... at a fixed mass threshold, e.g., by a factor of 5.0 ± 1.2 at M 500 = 2.5 × 1014 h –1 M sun between z = 0 and 0.5. This evolution reflects the growth of density perturbations, and can be used for the cosmological constraints complementing those from the distance-redshift relation....
Cosmological principles. II. Physical principles
International Nuclear Information System (INIS)
Harrison, E.R.
1974-01-01
The discussion of cosmological principle covers the uniformity principle of the laws of physics, the gravitation and cognizability principles, and the Dirac creation, chaos, and bootstrap principles. (U.S.)
Bianchi type II brane-world cosmologies (U≥0)
International Nuclear Information System (INIS)
Hoogen, R.J. van den; Ibanez, J.
2003-01-01
The asymptotic properties of the Bianchi type II cosmological model in the brane-world scenario are investigated. The matter content is assumed to be a combination of a perfect fluid and a minimally coupled scalar field that is restricted to the brane. The isotropic brane-world solution is determined to represent the initial singularity in all brane-world cosmologies. Additionally, it is shown that it is the kinetic energy of the scalar field which dominates the initial dynamics in these brane-world cosmologies. It is important to note that the dynamics of these brane-world cosmologies is not necessarily asymptotic to general relativistic cosmologies to the future in the case of a zero four-dimensional cosmological constant
Chandra Cluster Cosmology Project III: Cosmological Parameter Constraints
DEFF Research Database (Denmark)
Vikhlinin, A.; Kravtsov, A. V.; Burenin, R. A.
2009-01-01
function evolution to be used as a useful growth of a structure-based dark energy probe. In this paper, we present cosmological parameter constraints obtained from Chandra observations of 37 clusters with langzrang = 0.55 derived from 400 deg2 ROSAT serendipitous survey and 49 brightest z ≈ 0.05 clusters...
CHANDRA CLUSTER COSMOLOGY PROJECT III: COSMOLOGICAL PARAMETER CONSTRAINTS
International Nuclear Information System (INIS)
Vikhlinin, A.; Forman, W. R.; Jones, C.; Murray, S. S.; Kravtsov, A. V.; Burenin, R. A.; Voevodkin, A.; Ebeling, H.; Hornstrup, A.; Nagai, D.; Quintana, H.
2009-01-01
Chandra observations of large samples of galaxy clusters detected in X-rays by ROSAT provide a new, robust determination of the cluster mass functions at low and high redshifts. Statistical and systematic errors are now sufficiently small, and the redshift leverage sufficiently large for the mass function evolution to be used as a useful growth of a structure-based dark energy probe. In this paper, we present cosmological parameter constraints obtained from Chandra observations of 37 clusters with (z) = 0.55 derived from 400 deg 2 ROSAT serendipitous survey and 49 brightest z ∼ 0.05 clusters detected in the All-Sky Survey. Evolution of the mass function between these redshifts requires Ω Λ > 0 with a ∼5σ significance, and constrains the dark energy equation-of-state parameter to w 0 = -1.14 ± 0.21, assuming a constant w and a flat universe. Cluster information also significantly improves constraints when combined with other methods. Fitting our cluster data jointly with the latest supernovae, Wilkinson Microwave Anisotropy Probe, and baryonic acoustic oscillation measurements, we obtain w 0 = -0.991 ± 0.045 (stat) ±0.039 (sys), a factor of 1.5 reduction in statistical uncertainties, and nearly a factor of 2 improvement in systematics compared with constraints that can be obtained without clusters. The joint analysis of these four data sets puts a conservative upper limit on the masses of light neutrinos Σm ν M h and σ 8 from the low-redshift cluster mass function.
Asymptotics with a positive cosmological constant II
Kesavan, Aruna; Ashtekar, Abhay; Bonga, Beatrice
2015-04-01
The study of isolated systems has been vastly successful in the context of vanishing cosmological constant, Λ = 0 . However, there is no physically useful notion of asymptotics for the universe we inhabit with Λ > 0 . This means that presently there is no fundamental understanding of gravitational waves in our own universe. The full non-linear framework is still under development, but some interesting results at the linearized level have been obtained. In particular, I will discuss the quadrupole formula for gravitational radiation and its implications.
Cosmologies with quasiregular singularities. II. Stability considerations
International Nuclear Information System (INIS)
Konkowski, D.A.; Helliwell, T.M.
1985-01-01
The stability properties of a class of spacetimes with quasiregular singularities is discussed. Quasiregular singularities are the end points of incomplete, inextendible geodesics at which the Riemann tensor and its derivatives remain at least bounded in all parallel-propagated orthonormal (PPON) frames; observers approaching such a singularity would find that their world lines come to an end in a finite proper time. The Taub-NUT (Newman-Unti-Tamburino)-type cosmologies investigated are R 1 x T 3 and R 3 x S 1 flat Kasner spacetimes, the two-parameter family of spatially homogeneous but anisotropic Bianchi type-IX Taub-NUT spacetimes, and an infinite-dimensional family of Einstein-Rosen-Gowdy spacetimes studied by Moncrief. The behavior of matter near the quasiregular singularity in each of these spacetimes is explored through an examination of the behavior of the stress-energy tensors and scalars for conformally coupled and minimally coupled, massive and massless scalar waves as observed in both coordinate and PPON frames. A conjecture is postulated concerning the stability of the nature of the singularity in these spacetimes. The conjecture for a Taub-NUT-type background spacetime is that if a test-field stress-energy tensor evaluated in a PPON frame mimics the behavior of the Riemann tensor components which indicate a particular type of singularity (quasiregular, nonscalar curvature, or scalar curvature), then a complete nonlinear backreaction calculation, in which the fields are allowed to influence the geometry, would show that this type of singularity actually occurs. Evidence supporting the conjecture is presented for spacetimes whose symmetries are unchanged when fields with the same symmetries are added
International Nuclear Information System (INIS)
Novikov, I.D.
1979-01-01
Progress made by this Commission over the period 1976-1978 is reviewed. Topics include the Hubble constant, deceleration parameter, large-scale distribution of matter in the universe, radio astronomy and cosmology, space astronomy and cosmology, formation of galaxies, physics near the cosmological singularity, and unconventional cosmological models. (C.F.)
Anisotropic Bianchi II cosmological models with matter and electromagnetic fields
International Nuclear Information System (INIS)
Soares, D.
1978-01-01
A class of solutions of Einstein-Maxwell equations is presented, which corresponds to anisotropic Bianchi II spatially homogeneous cosmological models with perfect fluid and electromagnetic field. A particular model is examined and shown to be unstable for perturbations of the electromagnetic field strength parameter about a particular value. This value defines a limiar unstable case in which the ratio epsilon, of the fluid density to the e.m. energy density is monotonically increasing with a minimum finite value at the singularity. Beyond this limiar, the model has a matter dominated singularity, and a characteristic stage appears where epsilon has a minimum, at a finite time from the singularity. For large times, the models tend to an exact solution for zero electromagnetic field and fluid with p = (1/5)p. Some cosmological features of the models are calculated, as the effect of anisotropy on matter density and expansion time scale factors, as compared to the corresponding Friedmann model [pt
PHOTOMETRIC SUPERNOVA COSMOLOGY WITH BEAMS AND SDSS-II
Energy Technology Data Exchange (ETDEWEB)
Hlozek, Renee [Oxford Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Kunz, Martin [Department de physique theorique, Universite de Geneve, 30, quai Ernest-Ansermet, CH-1211 Geneve 4 (Switzerland); Bassett, Bruce; Smith, Mat; Newling, James [African Institute for Mathematical Sciences, 68 Melrose Road, Muizenberg 7945 (South Africa); Varughese, Melvin [Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch, Cape Town, 7700 (South Africa); Kessler, Rick; Frieman, Joshua [The Kavli Institute for Cosmological Physics, The University of Chicago, 933 East 56th Street, Chicago, IL 60637 (United States); Bernstein, Joseph P.; Kuhlmann, Steve; Marriner, John [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Campbell, Heather; Lampeitl, Hubert; Nichol, Robert C. [Institute of Cosmology and Gravitation, Dennis Sciama Building Burnaby Road Portsmouth PO1 3FX (United Kingdom); Dilday, Ben [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Falck, Bridget; Riess, Adam G. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Sako, Masao [Department of Physics and Astronomy, University of Pennsylvania, 203 South 33rd Street, Philadelphia, PA 19104 (United States); Schneider, Donald P., E-mail: rhlozek@astro.princeton.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)
2012-06-20
Supernova (SN) cosmology without spectroscopic confirmation is an exciting new frontier, which we address here with the Bayesian Estimation Applied to Multiple Species (BEAMS) algorithm and the full three years of data from the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SN). BEAMS is a Bayesian framework for using data from multiple species in statistical inference when one has the probability that each data point belongs to a given species, corresponding in this context to different types of SNe with their probabilities derived from their multi-band light curves. We run the BEAMS algorithm on both Gaussian and more realistic SNANA simulations with of order 10{sup 4} SNe, testing the algorithm against various pitfalls one might expect in the new and somewhat uncharted territory of photometric SN cosmology. We compare the performance of BEAMS to that of both mock spectroscopic surveys and photometric samples that have been cut using typical selection criteria. The latter typically either are biased due to contamination or have significantly larger contours in the cosmological parameters due to small data sets. We then apply BEAMS to the 792 SDSS-II photometric SNe with host spectroscopic redshifts. In this case, BEAMS reduces the area of the {Omega}{sub m}, {Omega}{sub {Lambda}} contours by a factor of three relative to the case where only spectroscopically confirmed data are used (297 SNe). In the case of flatness, the constraints obtained on the matter density applying BEAMS to the photometric SDSS-II data are {Omega}{sup BEAMS}{sub m} = 0.194 {+-} 0.07. This illustrates the potential power of BEAMS for future large photometric SN surveys such as Large Synoptic Survey Telescope.
PHOTOMETRIC SUPERNOVA COSMOLOGY WITH BEAMS AND SDSS-II
International Nuclear Information System (INIS)
Hlozek, Renée; Kunz, Martin; Bassett, Bruce; Smith, Mat; Newling, James; Varughese, Melvin; Kessler, Rick; Frieman, Joshua; Bernstein, Joseph P.; Kuhlmann, Steve; Marriner, John; Campbell, Heather; Lampeitl, Hubert; Nichol, Robert C.; Dilday, Ben; Falck, Bridget; Riess, Adam G.; Sako, Masao; Schneider, Donald P.
2012-01-01
Supernova (SN) cosmology without spectroscopic confirmation is an exciting new frontier, which we address here with the Bayesian Estimation Applied to Multiple Species (BEAMS) algorithm and the full three years of data from the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SN). BEAMS is a Bayesian framework for using data from multiple species in statistical inference when one has the probability that each data point belongs to a given species, corresponding in this context to different types of SNe with their probabilities derived from their multi-band light curves. We run the BEAMS algorithm on both Gaussian and more realistic SNANA simulations with of order 10 4 SNe, testing the algorithm against various pitfalls one might expect in the new and somewhat uncharted territory of photometric SN cosmology. We compare the performance of BEAMS to that of both mock spectroscopic surveys and photometric samples that have been cut using typical selection criteria. The latter typically either are biased due to contamination or have significantly larger contours in the cosmological parameters due to small data sets. We then apply BEAMS to the 792 SDSS-II photometric SNe with host spectroscopic redshifts. In this case, BEAMS reduces the area of the Ω m , Ω Λ contours by a factor of three relative to the case where only spectroscopically confirmed data are used (297 SNe). In the case of flatness, the constraints obtained on the matter density applying BEAMS to the photometric SDSS-II data are Ω BEAMS m = 0.194 ± 0.07. This illustrates the potential power of BEAMS for future large photometric SN surveys such as Large Synoptic Survey Telescope.
International Nuclear Information System (INIS)
Contopoulos, G.; Kotsakis, D.
1987-01-01
An extensive first part on a wealth of observational results relevant to cosmology lays the foundation for the second and central part of the book; the chapters on general relativity, the various cosmological theories, and the early universe. The authors present in a complete and almost non-mathematical way the ideas and theoretical concepts of modern cosmology including the exciting impact of high-energy particle physics, e.g. in the concept of the ''inflationary universe''. The final part addresses the deeper implications of cosmology, the arrow of time, the universality of physical laws, inflation and causality, and the anthropic principle
Hybrid petacomputing meets cosmology: The Roadrunner Universe project
International Nuclear Information System (INIS)
Habib, Salman; Pope, Adrian; Lukic, Zarija; Daniel, David; Fasel, Patricia; Desai, Nehal; Heitmann, Katrin; Hsu, Chung-Hsing; Ankeny, Lee; Mark, Graham; Bhattacharya, Suman; Ahrens, James
2009-01-01
The target of the Roadrunner Universe project at Los Alamos National Laboratory is a set of very large cosmological N-body simulation runs on the hybrid supercomputer Roadrunner, the world's first petaflop platform. Roadrunner's architecture presents opportunities and difficulties characteristic of next-generation supercomputing. We describe a new code designed to optimize performance and scalability by explicitly matching the underlying algorithms to the machine architecture, and by using the physics of the problem as an essential aid in this process. While applications will differ in specific exploits, we believe that such a design process will become increasingly important in the future. The Roadrunner Universe project code, MC 3 (Mesh-based Cosmology Code on the Cell), uses grid and direct particle methods to balance the capabilities of Roadrunner's conventional (Opteron) and accelerator (Cell BE) layers. Mirrored particle caches and spectral techniques are used to overcome communication bandwidth limitations and possible difficulties with complicated particle-grid interaction templates.
García-Bellido, J
2015-01-01
In these lectures I review the present status of the so-called Standard Cosmological Model, based on the hot Big Bang Theory and the Inflationary Paradigm. I will make special emphasis on the recent developments in observational cosmology, mainly the acceleration of the universe, the precise measurements of the microwave background anisotropies, and the formation of structure like galaxies and clusters of galaxies from tiny primordial fluctuations generated during inflation.
Vittorio, Nicola
2018-01-01
Modern cosmology has changed significantly over the years, from the discovery to the precision measurement era. The data now available provide a wealth of information, mostly consistent with a model where dark matter and dark energy are in a rough proportion of 3:7. The time is right for a fresh new textbook which captures the state-of-the art in cosmology. Written by one of the world's leading cosmologists, this brand new, thoroughly class-tested textbook provides graduate and undergraduate students with coverage of the very latest developments and experimental results in the field. Prof. Nicola Vittorio shows what is meant by precision cosmology, from both theoretical and observational perspectives.
Gravitational Waves in Locally Rotationally Symmetric (LRS Class II Cosmologies
Directory of Open Access Journals (Sweden)
Michael Bradley
2017-10-01
Full Text Available In this work we consider perturbations of homogeneous and hypersurface orthogonal cosmological backgrounds with local rotational symmetry (LRS, using a method based on the 1 + 1 + 2 covariant split of spacetime. The backgrounds, of LRS class II, are characterised by that the vorticity, the twist of the 2-sheets, and the magnetic part of the Weyl tensor all vanish. They include the flat Friedmann universe as a special case. The matter contents of the perturbed spacetimes are given by vorticity-free perfect fluids, but otherwise the perturbations are arbitrary and describe gravitational, shear, and density waves. All the perturbation variables can be given in terms of the time evolution of a set of six harmonic coefficients. This set decouples into one set of four coefficients with the density perturbations acting as source terms, and another set of two coefficients describing damped source-free gravitational waves with odd parity. We also consider the flat Friedmann universe, which has been considered by several others using the 1 + 3 covariant split, as a check of the isotropic limit. In agreement with earlier results we find a second-order wavelike equation for the magnetic part of the Weyl tensor which decouples from the density gradient for the flat Friedmann universes. Assuming vanishing vector perturbations, including the density gradient, we find a similar equation for the electric part of the Weyl tensor, which was previously unnoticed.
The effective field theory of nonsingular cosmology: II
Energy Technology Data Exchange (ETDEWEB)
Cai, Yong; Li, Hai-Guang [University of Chinese Academy of Sciences, School of Physics, Beijing (China); Qiu, Taotao [Central China Normal University, Institute of Astrophysics, Wuhan (China); Piao, Yun-Song [University of Chinese Academy of Sciences, School of Physics, Beijing (China); Chinese Academy of Sciences, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China)
2017-06-15
Based on the effective field theory (EFT) of cosmological perturbations, we explicitly clarify the pathology in nonsingular cubic Galileon models and show how to cure it in EFT with new insights into this issue. With the least set of EFT operators that are capable to avoid instabilities in nonsingular cosmologies, we construct a nonsingular model dubbed the Genesis-inflation model, in which a slowly expanding phase (namely, Genesis) with increasing energy density is followed by slow-roll inflation. The spectrum of the primordial perturbation may be simulated numerically, which shows itself a large-scale cutoff, as the large-scale anomalies in CMB might be a hint for. (orig.)
Cosmological perturbations in the projectable version of Hořava-Lifshitz gravity
International Nuclear Information System (INIS)
Cerioni, Alessandro; Brandenberger, Robert H.
2011-01-01
We consider linear perturbations about a homogeneous and isotropic cosmological background in the projectable version of Hořava-Lifshitz gravity. Starting from the action for cosmological perturbations, we identify the canonically normalized fluctuation variables. We find that - in contrast to what happens in the non-projectable version of the theory - the extra scalar cosmological perturbation mode is already dynamical at the level of linear perturbations and is either ghost-like or tachyonic depending on the value of a free parameter. This indicates a problem for the projectable version of Hořava-Lifshitz gravity
International Nuclear Information System (INIS)
Alejaldre, C.; Gozalo, J.J.A.; Perez, J.B.; Magaria, F.C.; Diaz, J.R.C.; Perez, J.G.; Lopez-Fraguas, A.; Garcia, L.; Krivenski, V.I.; Martin, R.; Navarro, A.P.; Perea, A.; Rodriguez-Yunta, A.; Ayza, M.S.; Varias, A.
1990-01-01
The TJ-II device is a medium-size helical-axis stellarator to be built in Madrid. Its main characteristics are potential for high-beta operation; flexibility, i.e., its rotational transform can be varied over a wide range and its shear to some extent; and bean-shaped plasma cross section. The latest understanding of TJ-II physics in the fields of electron cyclotron resonance heating, transport, and magneto-hydrodynamics, and the engineering solutions introduced in its final design are discussed
Computational complexity of the landscape II-Cosmological considerations
Denef, Frederik; Douglas, Michael R.; Greene, Brian; Zukowski, Claire
2018-05-01
We propose a new approach for multiverse analysis based on computational complexity, which leads to a new family of "computational" measure factors. By defining a cosmology as a space-time containing a vacuum with specified properties (for example small cosmological constant) together with rules for how time evolution will produce the vacuum, we can associate global time in a multiverse with clock time on a supercomputer which simulates it. We argue for a principle of "limited computational complexity" governing early universe dynamics as simulated by this supercomputer, which translates to a global measure for regulating the infinities of eternal inflation. The rules for time evolution can be thought of as a search algorithm, whose details should be constrained by a stronger principle of "minimal computational complexity". Unlike previously studied global measures, ours avoids standard equilibrium considerations and the well-known problems of Boltzmann Brains and the youngness paradox. We also give various definitions of the computational complexity of a cosmology, and argue that there are only a few natural complexity classes.
The concept of fractal cosmos: II. Modern cosmology
Grujic, P. V.
Development of the concept of fractal cosmos after Anaxagoras has been followed up to the present. It is shown how the concept reappeared in the early Renaissance as a vague idea and subsequently took up a concrete formulation at the beginning of the 20-eth century. The modern cosmology state of affairs has been considered in view of the fractal paradigm and the current disputes and controversies discussed. It is argued that the concept of the hierarchical cosmos is still alive and might become an essential ingredient within the modern view of the universe.
The concept of fractal cosmos: II Modern cosmology
Directory of Open Access Journals (Sweden)
Grujić Petar V.
2002-01-01
Full Text Available Development of the concept of fractal cosmos after Anaxagoras has been followed up to the present. It is shown how the concept reappeared in the early Renaissance as a vague idea and subsequently took up a concrete formulation at the beginning of the 20-eth century. The modern cosmology state of affairs has been considered in view of the fractal paradigm and the current disputes and controversies discussed. It is argued that the concept of the hierarchical cosmos is still alive and might become an essential ingredient within the modern view of the universe.
DEFF Research Database (Denmark)
Hovden, Jan
2008-01-01
The Hovdabrekka group is a group of nordic researchers doing survey studies of Nordic journalism schools (2005,2008). This site is dedicated to information from this project. The current members are: Norway: Rune Ottosen,Gunn Bjørnsen and Jan Fredrik Hovden Sweden: Jenny Wiik Denmark: Ida Willig...... and Jannie Møller Hartley. Finland: Henrika Zilliacus-Tikkanen and Raimo Solokangas Former members: Jan Dyberg and Hanne Jørndrup (Denmark), Marina Ghersetti (Sweden) Project Hovdabrekka originated at the Nordic conference for journalist teachers at Hovdabrekka, Iceland September 2004, where a small group...... of scientists/lecturers assembled with a desire to do a comparative quantitative study of students at Nordic journalism schools. Until very recently, there existed little systematic knowledge on the students of journalism in the Nordic countries. For these reasons, the Hovdabrekka group planned and sent out...
Nonlinear evolution of f(R) cosmologies. II. Power spectrum
International Nuclear Information System (INIS)
Oyaizu, Hiroaki; Hu, Wayne; Lima, Marcos
2008-01-01
We carry out a suite of cosmological simulations of modified action f(R) models where cosmic acceleration arises from an alteration of gravity instead of dark energy. These models introduce an extra scalar degree of freedom which enhances the force of gravity below the inverse mass or Compton scale of the scalar. The simulations exhibit the so-called chameleon mechanism, necessary for satisfying local constraints on gravity, where this scale depends on environment, in particular, the depth of the local gravitational potential. We find that the chameleon mechanism can substantially suppress the enhancement of power spectrum in the nonlinear regime if the background field value is comparable to or smaller than the depth of the gravitational potentials of typical structures. Nonetheless power spectrum enhancements at intermediate scales remain at a measurable level for models even when the expansion history is indistinguishable from a cosmological constant, cold dark matter model. Simple scaling relations that take the linear power spectrum into a nonlinear spectrum fail to capture the modifications of f(R) due to the change in collapsed structures, the chameleon mechanism, and the time evolution of the modifications.
Galaxy mergers and active nuclei. II. Cosmological evolution
International Nuclear Information System (INIS)
Roos, N.
1985-01-01
Galaxy mergers may produce active galactic nuclei (AGNs) by repopulating stellar loss-cone orbits around a central black hole. In the companion paper we derived a local bolometric luminosity function of AGNs based on this process. In this paper we interpret the observed cosmological evolution of the luminosity function of AGNs as due to evolution of the merging rate among galaxies after their formation at a redshift of approx.3. An important difference between our model and previous (empirical) models is that the evolution depends on galactic (stellar) luminosity instead of central nonthermal luminosity. The radio counts at 1.4 GHz and optical counts are reproduced by the model if the merging rate of the galaxies at the bright end of the galaxy luminosity function evolves considerably faster than the merging rate of the smaller galaxies. The theoretical and observed luminosity functions at high redshift have similar characteristics: (i) at high luminosity the evolution is best described by luminosity evolution, and (2) the luminosity function has a maximum at approx.10 3 Gpc -3 , which is the space density of the most massive galaxies. A large fraction of these galaxies are presumably formed in the precursors of rich clusters. Their merger rate is high initially and declines rapidly on a time scale of a few billion years. If the initial density fluctuation spectrum for protoclusters of mass M/sub cl/ has the form deltarho/rhoproportionalM/sup( -1+n//3)/2/sub cl/, then the steep evolution of the most luminous galaxies suggests nroughly-equal-1.3 at a redshift of approx.3, which is consistent with the observed clustering of galaxies
Hořava–Lifshitz gravity inspired Bianchi-II cosmology and the mixmaster universe
International Nuclear Information System (INIS)
Giani, Leonardo; Kamenshchik, Alexander Y
2017-01-01
We study different aspects of the Hořava-Lifshitz inspired Bianchi-II cosmology and its relations with the mixmaster universe model. First, we present exact solutions for a toy model, where only the cubic in spatial curvature terms are present in the action; then we briefly discuss some exotic singularities, which can appear in this toy model. We study also the toy model where only the quadratic in spatial curvature terms are present in the action. We establish relations between our results and those obtained by using the Hamiltonian formalism. Finally, we apply the results obtained by studying Bianchi-II cosmology to describe the evolution of the mixmaster universe in terms of the Belinsky–Khalatnikov–Lifshitz formalism. Generally, our analysis gives some arguments in favour of the existence of the oscillatory approach to the singularity in a universe governed by the Hořava–Lifshitz type gravity. (paper)
LRS Bianchi Type II Massive String Cosmological Models with Magnetic Field in Lyra's Geometry
Directory of Open Access Journals (Sweden)
Raj Bali
2013-01-01
Full Text Available Bianchi type II massive string cosmological models with magnetic field and time dependent gauge function ( in the frame work of Lyra's geometry are investigated. The magnetic field is in -plane. To get the deterministic solution, we have assumed that the shear ( is proportional to the expansion (. This leads to , where and are metric potentials and is a constant. We find that the models start with a big bang at initial singularity and expansion decreases due to lapse of time. The anisotropy is maintained throughout but the model isotropizes when . The physical and geometrical aspects of the model in the presence and absence of magnetic field are also discussed.
II José Plínio Baptista School of Cosmology
Piattella, Oliver; Rodrigues, Davi; Velten, Hermano; Zimdahl, Winfried
2016-01-01
The series of texts composing this book is based on the lectures presented during the II José Plínio Baptista School of Cosmology, held in Pedra Azul (Espírito Santo, Brazil) between 9 and 14 March 2014. This II JBPCosmo has been entirely devoted to the problem of understanding theoretical and observational aspects of Cosmic Background Radiation (CMB). The CMB is one of the most important phenomena in Physics and a fundamental probe of our Universe when it was only 400,000 years old. It is an extraordinary laboratory where we can learn from particle physics to cosmology; its discovery in 1965 has been a landmark event in the history of physics. The observations of the anisotropy of the cosmic microwave background radiation through the satellites COBE, WMAP and Planck provided a huge amount of data which are being analyzed in order to discover important information regarding the composition of our universe and the process of structure formation.
Jones, Bernard J. T.
2017-04-01
Preface; Notation and conventions; Part I. 100 Years of Cosmology: 1. Emerging cosmology; 2. The cosmic expansion; 3. The cosmic microwave background; 4. Recent cosmology; Part II. Newtonian Cosmology: 5. Newtonian cosmology; 6. Dark energy cosmological models; 7. The early universe; 8. The inhomogeneous universe; 9. The inflationary universe; Part III. Relativistic Cosmology: 10. Minkowski space; 11. The energy momentum tensor; 12. General relativity; 13. Space-time geometry and calculus; 14. The Einstein field equations; 15. Solutions of the Einstein equations; 16. The Robertson-Walker solution; 17. Congruences, curvature and Raychaudhuri; 18. Observing and measuring the universe; Part IV. The Physics of Matter and Radiation: 19. Physics of the CMB radiation; 20. Recombination of the primeval plasma; 21. CMB polarisation; 22. CMB anisotropy; Part V. Precision Tools for Precision Cosmology: 23. Likelihood; 24. Frequentist hypothesis testing; 25. Statistical inference: Bayesian; 26. CMB data processing; 27. Parametrising the universe; 28. Precision cosmology; 29. Epilogue; Appendix A. SI, CGS and Planck units; Appendix B. Magnitudes and distances; Appendix C. Representing vectors and tensors; Appendix D. The electromagnetic field; Appendix E. Statistical distributions; Appendix F. Functions on a sphere; Appendix G. Acknowledgements; References; Index.
Military Family Coping Project - Phase II
2015-05-01
Anxiety, Life Satisfaction , Addiction, Trauma 4 The Military Family Coping Project reflects two phases. The first consisted of a series of focus...need for and guided the work of the Military Family Coping Project Phase II funded by TATRC. The Military Family Coping Project Phase II was...solidarity. For the purposes of family functioning analyses, married and unmarried soldiers were analyzed separately because marital status affects
Cosmological parameter uncertainties from SALT-II type Ia supernova light curve models
International Nuclear Information System (INIS)
Mosher, J.; Sako, M.; Guy, J.; Astier, P.; Betoule, M.; El-Hage, P.; Pain, R.; Regnault, N.; Kessler, R.; Frieman, J. A.; Marriner, J.; Biswas, R.; Kuhlmann, S.; Schneider, D. P.
2014-01-01
We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ∼120 low-redshift (z < 0.1) SNe Ia, ∼255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ∼290 SNLS SNe Ia (z ≤ 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w input – w recovered ) ranging from –0.005 ± 0.012 to –0.024 ± 0.010. These biases are indistinguishable from each other within the uncertainty; the average bias on w is –0.014 ± 0.007.
Cosmological Parameter Uncertainties from SALT-II Type Ia Supernova Light Curve Models
Energy Technology Data Exchange (ETDEWEB)
Mosher, J. [Pennsylvania U.; Guy, J. [LBL, Berkeley; Kessler, R. [Chicago U., KICP; Astier, P. [Paris U., VI-VII; Marriner, J. [Fermilab; Betoule, M. [Paris U., VI-VII; Sako, M. [Pennsylvania U.; El-Hage, P. [Paris U., VI-VII; Biswas, R. [Argonne; Pain, R. [Paris U., VI-VII; Kuhlmann, S. [Argonne; Regnault, N. [Paris U., VI-VII; Frieman, J. A. [Fermilab; Schneider, D. P. [Penn State U.
2014-08-29
We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ~120 low-redshift (z < 0.1) SNe Ia, ~255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ~290 SNLS SNe Ia (z ≤ 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w (input) – w (recovered)) ranging from –0.005 ± 0.012 to –0.024 ± 0.010. These biases are indistinguishable from each other within the uncertainty, the average bias on w is –0.014 ± 0.007.
Project planning and project management of Baseball II-T
International Nuclear Information System (INIS)
Kozman, T.A.; Chargin, A.K.
1975-01-01
The details of the project planning and project management work done on the Baseball II-T experiment are reviewed. The LLL Baseball program is a plasma confinement experiment accomplished with a superconducting magnet in the shape of a baseball seam. Both project planning and project management made use of the Critical Path Management (CPM) computer code. The computer code, input, and results from the project planning and project management runs, and the cost and effectiveness of this method of systems planning are discussed
Cosmological models in globally geodesic coordinates. II. Near-field approximation
International Nuclear Information System (INIS)
Liu Hongya
1987-01-01
A near-field approximation dealing with the cosmological field near a typical freely falling observer is developed within the framework established in the preceding paper [J. Math. Phys. 28, xxxx(1987)]. It is found that for the matter-dominated era the standard cosmological model of general relativity contains the Newtonian cosmological model, proposed by Zel'dovich, as its near-field approximation in the observer's globally geodesic coordinate system
International Nuclear Information System (INIS)
Caprini, Chiara; Hindmarsh, Mark; Helsinki Univ.; Huber, Stephan
2016-04-01
We investigate the potential for the eLISA space-based interferometer to detect the stochastic gravitational wave background produced by strong first-order cosmological phase transitions. We discuss the resulting contributions from bubble collisions, magnetohydrodynamic turbulence, and sound waves to the stochastic background, and estimate the total corresponding signal predicted in gravitational waves. The projected sensitivity of eLISA to cosmological phase transitions is computed in a model-independent way for various detector designs and configurations. By applying these results to several specific models, we demonstrate that eLISA is able to probe many well-motivated scenarios beyond the Standard Model of particle physics predicting strong first-order cosmological phase transitions in the early Universe.
Project Final Report: HPC-Colony II
Energy Technology Data Exchange (ETDEWEB)
Jones, Terry R [ORNL; Kale, Laxmikant V [University of Illinois, Urbana-Champaign; Moreira, Jose [IBM T. J. Watson Research Center
2013-11-01
This report recounts the HPC Colony II Project which was a computer science effort funded by DOE's Advanced Scientific Computing Research office. The project included researchers from ORNL, IBM, and the University of Illinois at Urbana-Champaign. The topic of the effort was adaptive system software for extreme scale parallel machines. A description of findings is included.
Andrianov, Alexander A.; Espriu, D. (Domènec); Andrianov, Vladimir A.; Kolevatov, S.
2014-01-01
This publication contains the proceedings of the II Russian-Spanish Congress on Particle and Nuclear Physics at All Scales, Astroparticle Physics and Cosmology, a collection of refereed papers presented in plenary and parallel sessions at a meeting that gathered leading Russian and Spanish Scientists in the above fields in Saint-Petersburg from October 1st through October 4th 2013 (http://hep.phys.spbu.ru/conf/esp-rus2013/).
The Sudbury Neutrino Observatory project and the Kamiokande II project
International Nuclear Information System (INIS)
Beier, E.W.
1991-01-01
This document is a technical progress report on work performed at the University of Pennsylvania during the current year on the Sudbury Neutrino Observatory project and on the Kamiokande II project. The motivation for both experiments is the measurement of neutrinos emitted by the sun. The Kamiokande II experiment was an adaptation of an existing nucleon decay detector located in Japan to search for neutrinos emitted by the sun. It has been operational since 1986. Data taking was concluded in 1990 and work will terminate at the end of this grant year. The topics discussed in this report are: the Sudbury Neutrino Observatory project; photomultiplier tube measurements; photomultiplier bases; signal processing electronics; electronics system issues; software management and development; and Kamiokande II
Energy Technology Data Exchange (ETDEWEB)
Heitmann, Katrin [Los Alamos National Laboratory; Habib, Salman [Los Alamos National Laboratory; Higdon, David [Los Alamos National Laboratory; Williams, Brian J [Los Alamos National Laboratory; White, Martin [Los Alamos National Laboratory; Wagner, Christian [Los Alamos National Laboratory
2008-01-01
The power spectrum of density fluctuations is a foundational source of cosmological information. Precision cosmological probes targeted primarily at investigations of dark energy require accurate theoretical determinations of the power spectrum in the nonlinear regime. To exploit the observational power of future cosmological surveys, accuracy demands on the theory are at the one percent level or better. Numerical simulations are currently the only way to produce sufficiently error-controlled predictions for the power spectrum. The very high computational cost of (precision) N-body simulations is a major obstacle to obtaining predictions in the nonlinear regime, while scanning over cosmological parameters. Near-future observations, however, are likely to provide a meaningful constraint only on constant dark energy equation of state 'wCDM' cosmologies. In this paper we demonstrate that a limited set of only 37 cosmological models -- the 'Coyote Universe' suite -- can be used to predict the nonlinear matter power spectrum at the required accuracy over a prior parameter range set by cosmic microwave background observations. This paper is the second in a series of three, with the final aim to provide a high-accuracy prediction scheme for the nonlinear matter power spectrum for wCDM cosmologies.
Venkateswarlu, R.; Sreenivas, K.
2014-06-01
The LRS Bianchi type-I and type-II string cosmological models are studied when the source for the energy momentum tensor is a bulk viscous stiff fluid containing one dimensional strings together with zero-mass scalar field. We have obtained the solutions of the field equations assuming a functional relationship between metric coefficients when the metric is Bianchi type-I and constant deceleration parameter in case of Bianchi type-II metric. The physical and kinematical properties of the models are discussed in each case. The effects of Viscosity on the physical and kinematical properties are also studied.
Health Activities Project (HAP), Trial Edition II.
Buller, Dave; And Others
Contained within this Health Activities Project (HAP) trial edition (set II) are a teacher information folio and numerous student activity folios which center around the idea that students in grades 5-8 can control their own health and safety. Each student folio is organized into a Synopsis, Health Background, Materials, Setting Up, and Activities…
Wallace, Colin S.; Prather, Edward E.; Duncan, Douglas K.
2011-01-01
This is the second of five papers detailing our national study of general education astronomy students' conceptual and reasoning difficulties with cosmology. This article begins our quantitative investigation of the data. We describe how we scored students' responses to four conceptual cosmology surveys, and we present evidence for the inter-rater…
Ex-Nihilo II: Examination Syllabi and the Sequencing of Cosmology Education
Pimbblet, Kevin A.; Newman, John C.
2003-01-01
Cosmology education has become an integral part of modern physics courses. Directed by National Curricula, major UK examination boards have developed syllabi that contain explicit statements about the model of the Big Bang and the strong observational evidence that supports it. This work examines the similarities and differences in these…
Energy Technology Data Exchange (ETDEWEB)
Pesce, D. W. [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Braatz, J. A.; Condon, J. J.; Gao, F.; Lo, K. Y. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Henkel, C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Litzinger, E. [Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Emil-Fischer-Str. 31, D-97074 Würzburg (Germany); Reid, M. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2015-09-01
We use single-dish radio spectra of known 22 GHz H{sub 2}O megamasers, primarily gathered from the large data set observed by the Megamaser Cosmology Project, to identify Keplerian accretion disks and to investigate several aspects of the disk physics. We test a mechanism for maser excitation proposed by Maoz and McKee (1998), whereby population inversion arises in gas behind spiral shocks traveling through the disk. Though the flux of redshifted features is larger on average than that of blueshifted features, in support of the model, the high-velocity features show none of the predicted systematic velocity drifts. We find rapid intra-day variability in the maser spectrum of ESO 558−G009 that is likely the result of interstellar scintillation, for which we favor a nearby (D ≈ 70 pc) scattering screen. In a search for reverberation in six well-sampled sources, we find that any radially propagating signal must be contributing ≲10% of the total variability. We also set limits on the magnetic field strengths in seven sources, using strong flaring events to check for the presence of Zeeman splitting. These limits are typically 200–300 mG (1σ), but our most stringent limits reach down to 73 mG for the galaxy NGC 1194.
International Nuclear Information System (INIS)
Boening, K.
1994-01-01
The new research reactor FRM-II at Garching near Munich is planned to become a high performance source of slow neutrons in Germany. Its design concept provides for a very compact reactor core cooled by light water and placed within a heavy water moderator tank, where a high thermal neutron flux will be obtained at only 20 MW power. - This paper begins with an overview over some of the essential design features and some more recent design modifications. It then reports on the status of the project, the most important event being a positive decision which the Bavarian State Government has made in January 1993 and which represented a green light for the project to enter the next project phase. Consequently, two official requests have been made by the Technical University of Munich, one for the nuclear licensing of the facility and the other for the so called 'Raumordnungsverfahren'. In this context the final version of the FRM-II safety report has been submitted to the nuclear licensing authority. (author)
International Nuclear Information System (INIS)
Montoya, G.M.
1993-02-01
This final report addresses the decommissioning of the LAPRE II Reactor, safety enclosure, fuel reservoir tanks, emergency fuel recovery system, primary pump pit, secondary loop, associated piping, and the post-remediation activities. Post-remedial action measurements are also included. The cost of the project including, Phase I assessment and Phase II remediation was approximately $496K. The decommissioning operation produced 533 M 3 of mixed waste
International Nuclear Information System (INIS)
Montoya, G.M.
1992-01-01
This final report addresses the decommissioning of the LAPRE II Reactor, safety enclosure, fuel reservoir tanks, emergency fuel recovery system, primary pump pit, secondary loop, associated piping, and the post-remediation activities. Post-remedial action measurements are also included. The cost of the project, including Phase I assessment and Phase II remediation was approximately $496K. The decommissioning operation produced 533 m 3 of low-level solid radioactive waste and 5 m 3 of mixed waste
Combined Final Report for Colony II Project
Energy Technology Data Exchange (ETDEWEB)
Kale, Laxmikant [University of Illinois; Jones, Terry [Oak Ridge National Laboratory; Moreira, Jose [IBM Corp.
2013-10-23
(This report was originally submmited by the lead PI (Terry Jones, ORNL) on October 22, 2013 to the program manager, Lucy Nowell. It is being submitted from University of Illinois in accordance with instructions). HPC Colony II seeks to provide portable performance for leadership class machines. Our strategy is based on adaptive system software that aims to make the intelligent decisions necessary to allow domain scientists to safely focus on their task at hand and allow the system software stack to adapt their application to the underlying architecture. This report describes the research undertaken towards these objectives and the results obtained over the performance period of the project.
Chamcham, Khalil; Silk, Joseph; Barrow, John D.; Saunders, Simon
2017-04-01
Part I. Issues in the Philosophy of Cosmology: 1. Cosmology, cosmologia and the testing of cosmological theories George F. R. Ellis; 2. Black holes, cosmology and the passage of time: three problems at the limits of science Bernard Carr; 3. Moving boundaries? - comments on the relationship between philosophy and cosmology Claus Beisbart; 4. On the question why there exists something rather than nothing Roderich Tumulka; Part II. Structures in the Universe and the Structure of Modern Cosmology: 5. Some generalities about generality John D. Barrow; 6. Emergent structures of effective field theories Jean-Philippe Uzan; 7. Cosmological structure formation Joel R. Primack; 8. Formation of galaxies Joseph Silk; Part III. Foundations of Cosmology: Gravity and the Quantum: 9. The observer strikes back James Hartle and Thomas Hertog; 10. Testing inflation Chris Smeenk; 11. Why Boltzmann brains do not fluctuate into existence from the de Sitter vacuum Kimberly K. Boddy, Sean M. Carroll and Jason Pollack; 12. Holographic inflation revised Tom Banks; 13. Progress and gravity: overcoming divisions between general relativity and particle physics and between physics and HPS J. Brian Pitts; Part IV. Quantum Foundations and Quantum Gravity: 14. Is time's arrow perspectival? Carlo Rovelli; 15. Relational quantum cosmology Francesca Vidotto; 16. Cosmological ontology and epistemology Don N. Page; 17. Quantum origin of cosmological structure and dynamical reduction theories Daniel Sudarsky; 18. Towards a novel approach to semi-classical gravity Ward Struyve; Part V. Methodological and Philosophical Issues: 19. Limits of time in cosmology Svend E. Rugh and Henrik Zinkernagel; 20. Self-locating priors and cosmological measures Cian Dorr and Frank Arntzenius; 21. On probability and cosmology: inference beyond data? Martin Sahlén; 22. Testing the multiverse: Bayes, fine-tuning and typicality Luke A. Barnes; 23. A new perspective on Einstein's philosophy of cosmology Cormac O
THE MEGAMASER COSMOLOGY PROJECT. VIII. A GEOMETRIC DISTANCE TO NGC 5765b
Energy Technology Data Exchange (ETDEWEB)
Gao, F.; Zhao, W. [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Science, Shanghai 200030 (China); Braatz, J. A.; Lo, K. Y.; Condon, J. J.; Impellizzeri, C. M. V. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Reid, M. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Henkel, C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Kuo, C. Y. [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Pesce, D. W. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)
2016-02-01
As part of the Megamaser Cosmology Project, here we present a new geometric distance measurement to the megamaser galaxy NGC 5765b. Through a series of very long baseline interferometry observations, we have confirmed the water masers trace a thin, sub-parsec Keplerian disk around the nucleus, implying an enclosed mass of 4.55 ± 0.40 × 10{sup 7} M{sub ⊙}. Meanwhile, from single-dish monitoring of the maser spectra over two years, we measured the secular drifts of maser features near the systemic velocity of the galaxy with rates between 0.5 and 1.2 km s{sup −1} yr{sup −1}. Fitting a warped, thin-disk model to these measurements, we determine a Hubble Constant H{sub 0} of 66.0 ± 6.0 km s{sup −1} Mpc{sup −1} with an angular-diameter distance to NGC 5765b of 126.3 ± 11.6 Mpc. Apart from the distance measurement, we also investigate some physical properties related to the maser disk in NGC 5765b. The high-velocity features are spatially distributed into several clumps, which may indicate the existence of a spiral density wave associated with the accretion disk. For the redshifted features, the envelope defined by the peak maser intensities increases with radius. The profile of the systemic masers in NGC 5765b is smooth and shows almost no structural changes over the two years of monitoring time, which differs from the more variable case of NGC 4258.
Jones, D. O.; Scolnic, D. M.; Riess, A. G.; Rest, A.; Kirshner, R. P.; Berger, E.; Kessler, R.; Pan, Y.-C.; Foley, R. J.; Chornock, R.; Ortega, C. A.; Challis, P. J.; Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Huber, M. E.; Kaiser, N.; Kudritzki, R.-P.; Metcalfe, N.; Tonry, J.; Wainscoat, R. J.; Waters, C.; Gall, E. E. E.; Kotak, R.; McCrum, M.; Smartt, S. J.; Smith, K. W.
2018-04-01
We use 1169 Pan-STARRS supernovae (SNe) and 195 low-z (z used to infer unbiased cosmological parameters by using a Bayesian methodology that marginalizes over core-collapse (CC) SN contamination. Our sample contains nearly twice as many SNe as the largest previous SN Ia compilation. Combining SNe with cosmic microwave background (CMB) constraints from Planck, we measure the dark energy equation-of-state parameter w to be ‑0.989 ± 0.057 (stat+sys). If w evolves with redshift as w(a) = w 0 + w a (1 ‑ a), we find w 0 = ‑0.912 ± 0.149 and w a = ‑0.513 ± 0.826. These results are consistent with cosmological parameters from the Joint Light-curve Analysis and the Pantheon sample. We try four different photometric classification priors for Pan-STARRS SNe and two alternate ways of modeling CC SN contamination, finding that no variant gives a w differing by more than 2% from the baseline measurement. The systematic uncertainty on w due to marginalizing over CC SN contamination, {σ }wCC}=0.012, is the third-smallest source of systematic uncertainty in this work. We find limited (1.6σ) evidence for evolution of the SN color-luminosity relation with redshift, a possible systematic that could constitute a significant uncertainty in future high-z analyses. Our data provide one of the best current constraints on w, demonstrating that samples with ∼5% CC SN contamination can give competitive cosmological constraints when the contaminating distribution is marginalized over in a Bayesian framework.
International Nuclear Information System (INIS)
Maeda, Hideki; Harada, Tomohiro; Carr, B. J.
2008-01-01
We use a combination of numerical and analytical methods, exploiting the equations derived in a preceding paper, to classify all spherically symmetric self-similar solutions which are asymptotically Friedmann at large distances and contain a perfect fluid with equation of state p=(γ-1)μ with 0<γ<2/3. The expansion of the Friedmann universe is accelerated in this case. We find a one-parameter family of self-similar solutions representing a black hole embedded in a Friedmann background. This suggests that, in contrast to the positive pressure case, black holes in a universe with dark energy can grow as fast as the Hubble horizon if they are not too large. There are also self-similar solutions which contain a central naked singularity with negative mass and solutions which represent a Friedmann universe connected to either another Friedmann universe or some other cosmological model. The latter are interpreted as self-similar cosmological white hole or wormhole solutions. The throats of these wormholes are defined as two-dimensional spheres with minimal area on a spacelike hypersurface and they are all nontraversable because of the absence of a past null infinity
Quantum kinematics of spacetime. II. A model quantum cosmology with real clocks
International Nuclear Information System (INIS)
Hartle, J.B.
1988-01-01
Nonrelativistic model quantum cosmologies are studied in which the basic time variable is the position of a clock indicator and the time parameter of the Schroedinger equation is an unobservable label. Familiar Schroedinger-Heisenberg quantum mechanics emerges if the clock is ideal: arbitrarily accurate for arbitrarily long times. More realistically, however, the usual formulation emerges only as an approximation appropriate to states of this model universe in which part of the system functions approximately as an ideal clock. It is suggested that the quantum kinematics of spacetime theories such as general relativity may be analogous to those of this model. In particular it is suggested that our familiar notion of time in quantum mechanics is not an inevitable property of a general quantum framework but an approximate feature of specific initial conditions
HORIZON 2020 - Project SITEX-II
International Nuclear Information System (INIS)
Nachmilner, L.
2016-01-01
In the mid of 2015 a coordination action SITEX-II was initiated within the EC programme Horizon 2020. It aims at implementing in practice activities along with the interaction models issued by the SITEX project (carried out within FP7 programme in 2012-13), in view of developing an Expertise function network. This network is expected to ensure sustainable capacity of developing and coordination joint and harmonised activities related to the independent technical expertise in the field of safety of deep geological disposal of radioactive waste. SITEX-II tasks include: • The definition of the Strategic Research Agenda (SRA) based on the common R orientations defined by SITEX, the definition of ToR for the implementation of specific topics of from the SRA, and the interaction with IGD-TP and other external entities mandated to implement research on radioactive waste disposal regarding the potential setting up of a respective European Joint Programming; • The production of a guidance on the technical review of the safety case at its different phases of development, fostering a common understanding on the interpretation and proper implementation of safety requirements for developing, operating and closing a geological repository and on then verification of compliance with these requirements; • The commitment of a Civil Society (CS) in the definition of the SRA mentioned above, considering the expectations and technical questions to be considered when developing R for the purpose of Expert function. Close interactions between experts conducting the review work and CS representatives will enhance establishing the safety culture and, more globally, proposing governance patterns with CS in the framework of geological disposal; • The preparation of the ‚administrative‘ framework for creating a sustainable network of Technical Safety Organisations from EU members states by addressing the legal organisational and management aspects. (author)
International Nuclear Information System (INIS)
Wainwright, J.
1990-01-01
The workshop on mathematical cosmology was devoted to four topics of current interest. This report contains a brief discussion of the historical background of each topic and a concise summary of the content of each talk. The topics were; the observational cosmology program, the cosmological perturbation program, isotropic singularities, and the evolution of Bianchi cosmologies. (author)
FEBEX II Project THG Laboratory Experiments
International Nuclear Information System (INIS)
Missana, T.
2004-01-01
The main roles of the bentonite in a radioactive waste repository is to act as a geochemical barrier against the radionuclides migration. The effectiveness of this geochemical barrier depends on the surface properties of the solid phases and on the physico-chemical environment generated by the interaction of the solid phases with the groundwater. Within the FEBEX (Full-scale Engineered Barriers Experiment) project, a program of laboratory tests was designed to study and to understand the processes taking place in the clay barrier. Since the first stages of the project, these laboratory tests enabled to isolate different processes, making easier their interpretation, and provided fundamental parameters to be used in the Thermo Hydro Mechanical (THM) and Thermo Hydro Geochemical (THG) models. Additionally, experimental data enabled to check the predictive capability of these models. In the second phase of the project, laboratory tests focused on all those relevant aspects not sufficiently covered during FEBEX I. Particularly, the following main objectives were proposed for the THG investigations during FEBEX II : Attainment of a reliable description of the pore water chemistry at different geochemical conditions. Identification of the different types of water present in the bentonite and to determine the amount of available water for the solute transport.Evaluation of the potential effects of the extraction pressure in the chemical composition of the water obtained by squeezing methods.Study of the effects of the exchange complex in the rheological properties of the clay.Identification and modelling of the surface processes occurring in smectite, determination of the solubility constants of smectite and the formation constants of the surface complexes.Understanding of the mechanisms involved in the sorption of different radionuclides in the bentonite. Investigation of the diffusion mechanisms of conservative neutral and anionic species to have a deeper insight on the
FEBEX II Project THG Laboratory Experiments
Energy Technology Data Exchange (ETDEWEB)
Missana, T.
2004-07-01
The main roles of the bentonite in a radioactive waste repository is to act as a geochemical barrier against the radionuclides migration. The effectiveness of this geochemical barrier depends on the surface properties of the solid phases and on the physico-chemical environment generated by the interaction of the solid phases with the groundwater. Within the FEBEX (Full-scale Engineered Barriers Experiment) project, a program of laboratory tests was designed to study and to understand the processes taking place in the clay barrier. Since the first stages of the project, these laboratory tests enabled to isolate different processes, making easier their interpretation, and provided fundamental parameters to be used in the Thermo Hydro Mechanical (THM) and Thermo Hydro Geochemical (THG) models. Additionally, experimental data enabled to check the predictive capability of these models. In the second phase of the project, laboratory tests focused on all those relevant aspects not sufficiently covered during FEBEX I. Particularly, the following main objectives were proposed for the THG investigations during FEBEX II : Attainment of a reliable description of the pore water chemistry at different geochemical conditions. Identification of the different types of water present in the bentonite and to determine the amount of available water for the solute transport.Evaluation of the potential effects of the extraction pressure in the chemical composition of the water obtained by squeezing methods.Study of the effects of the exchange complex in the rheological properties of the clay.Identification and modelling of the surface processes occurring in smectite, determination of the solubility constants of smectite and the formation constants of the surface complexes.Understanding of the mechanisms involved in the sorption of different radionuclides in the bentonite. Investigation of the diffusion mechanisms of conservative neutral and anionic species to have a deeper insight on the
International Nuclear Information System (INIS)
Raychaudhuri, A.K.
1979-01-01
The subject is covered in chapters, entitled; introduction; Newtonian gravitation and cosmology; general relativity and relativistic cosmology; analysis of observational data; relativistic models not obeying the cosmological principle; microwave radiation background; thermal history of the universe and nucleosynthesis; singularity of cosmological models; gravitational constant as a field variable; cosmological models based on Einstein-Cartan theory; cosmological singularity in two recent theories; fate of perturbations of isotropic universes; formation of galaxies; baryon symmetric cosmology; assorted topics (including extragalactic radio sources; Mach principle). (U.K.)
Search for C II Emission on Cosmological Scales at Redshift Z ˜ 2.6
Pullen, Anthony R.; Serra, Paolo; Chang, Tzu-Ching; Doré, Olivier; Ho, Shirley
2018-05-01
We present a search for Cii emission over cosmological scales at high-redshifts. The Cii line is a prime candidate to be a tracer of star formation over large-scale structure since it is one of the brightest emission lines from galaxies. Redshifted Cii emission appears in the submillimeter regime, meaning it could potentially be present in the higher frequency intensity data from the Planck satellite used to measure the cosmic infrared background (CIB). We search for Cii emission over redshifts z = 2 - 3.2 in the Planck 545 GHz intensity map by cross-correlating the 3 highest frequency Planck maps with spectroscopic quasars and CMASS galaxies from the Sloan Digital Sky Survey III (SDSS-III), which we then use to jointly fit for Cii intensity, CIB parameters, and thermal Sunyaev-Zeldovich (SZ) emission. We report a measurement of an anomalous emission I_ν =6.6^{+5.0}_{-4.8}× 10^4Jy/sr at 95% confidence, which could be explained by Cii emission, favoring collisional excitation models of Cii emission that tend to be more optimistic than models based on Cii luminosity scaling relations from local measurements; however, a comparison of Bayesian information criteria reveal that this model and the CIB & SZ only model are equally plausible. Thus, more sensitive measurements will be needed to confirm the existence of large-scale Cii emission at high redshifts. Finally, we forecast that intensity maps from Planck cross-correlated with quasars from the Dark Energy Spectroscopic Instrument (DESI) would increase our sensitivity to Cii emission by a factor of 5, while the proposed Primordial Inflation Explorer (PIXIE) could increase the sensitivity further.
Boeyens, Jan CA
2010-01-01
The composition of the most remote objects brought into view by the Hubble telescope can no longer be reconciled with the nucleogenesis of standard cosmology and the alternative explanation, in terms of the LAMBDA-Cold-Dark-Matter model, has no recognizable chemical basis. A more rational scheme, based on the chemistry and periodicity of atomic matter, opens up an exciting new interpretation of the cosmos in terms of projective geometry and general relativity. The response of atomic structure to environmental pressure predicts non-Doppler cosmical redshifts and equilibrium nucleogenesis by alp
Energy Technology Data Exchange (ETDEWEB)
Martel, Hugo [Departement de physique, de genie physique et d' optique, Universite Laval, Quebec, QC (Canada); Barai, Paramita [Osservatorio Astronomico di Trieste, I-34143 Trieste (Italy); Brito, William [Centre de Recherche en Astrophysique du Quebec, C.P. 6128, Succ. Centre-Ville, Montreal, QC (Canada)
2012-09-20
We combine an N-body simulation algorithm with a subgrid treatment of galaxy formation, mergers, and tidal destruction, and an observed conditional luminosity function {Phi}(L|M), to study the origin and evolution of galactic and extragalactic light inside a cosmological volume of size (100 Mpc){sup 3}, in a concordance {Lambda}CDM model. This algorithm simulates the growth of large-scale structures and the formation of clusters, the evolution of the galaxy population in clusters, the destruction of galaxies by mergers and tides, and the evolution of the intracluster light (ICL). We find that destruction of galaxies by mergers dominates over destruction by tides by about an order of magnitude at all redshifts. However, tidal destruction is sufficient to produce ICL fractions f{sub ICL} that are sufficiently high to match observations. Our simulation produces 18 massive clusters (M{sub cl} > 10{sup 14} M{sub Sun }) with values of f{sub ICL} ranging from 1% to 58% at z = 0. There is a weak trend of f{sub ICL} to increase with cluster mass. The bulk of the ICL ({approx}60%) is provided by intermediate galaxies of total masses 10{sup 11}-10{sup 12} M{sub Sun} and stellar masses 6 Multiplication-Sign 10{sup 8} M{sub Sun} to 3 Multiplication-Sign 10{sup 10} M{sub Sun} that were tidally destroyed by even more massive galaxies. The contribution of low-mass galaxies to the ICL is small and the contribution of dwarf galaxies is negligible, even though, by numbers, most galaxies that are tidally destroyed are dwarfs. Tracking clusters back in time, we find that their values of f{sub ICL} tend to increase over time, but can experience sudden changes that are sometimes non-monotonic. These changes occur during major mergers involving clusters of comparable masses but very different intracluster luminosities. Most of the tidal destruction events take place in the central regions of clusters. As a result, the ICL is more centrally concentrated than the galactic light. Our results
International Nuclear Information System (INIS)
Martel, Hugo; Barai, Paramita; Brito, William
2012-01-01
We combine an N-body simulation algorithm with a subgrid treatment of galaxy formation, mergers, and tidal destruction, and an observed conditional luminosity function Φ(L|M), to study the origin and evolution of galactic and extragalactic light inside a cosmological volume of size (100 Mpc) 3 , in a concordance ΛCDM model. This algorithm simulates the growth of large-scale structures and the formation of clusters, the evolution of the galaxy population in clusters, the destruction of galaxies by mergers and tides, and the evolution of the intracluster light (ICL). We find that destruction of galaxies by mergers dominates over destruction by tides by about an order of magnitude at all redshifts. However, tidal destruction is sufficient to produce ICL fractions f ICL that are sufficiently high to match observations. Our simulation produces 18 massive clusters (M cl > 10 14 M ☉ ) with values of f ICL ranging from 1% to 58% at z = 0. There is a weak trend of f ICL to increase with cluster mass. The bulk of the ICL (∼60%) is provided by intermediate galaxies of total masses 10 11 -10 12 M ☉ and stellar masses 6 × 10 8 M ☉ to 3 × 10 10 M ☉ that were tidally destroyed by even more massive galaxies. The contribution of low-mass galaxies to the ICL is small and the contribution of dwarf galaxies is negligible, even though, by numbers, most galaxies that are tidally destroyed are dwarfs. Tracking clusters back in time, we find that their values of f ICL tend to increase over time, but can experience sudden changes that are sometimes non-monotonic. These changes occur during major mergers involving clusters of comparable masses but very different intracluster luminosities. Most of the tidal destruction events take place in the central regions of clusters. As a result, the ICL is more centrally concentrated than the galactic light. Our results support tidal destruction of intermediate-mass galaxies as a plausible scenario for the origin of the ICL.
Impact of National Fadama Development Project II on Rice farmers ...
African Journals Online (AJOL)
... examined the impact of National Fadama Development Project II on the profitability of rice farmers and assessed the extent to which the various innovations disseminated by the project were adopted by the rice farmer beneficiaries. The project which had all operating expenses cofinanced by the various key stakeholders ...
Cosmology and particle physics
International Nuclear Information System (INIS)
Turner, M.S.
1986-01-01
Progress in cosmology has become linked to progress in elementary particle physics. In these six lectures, the author illustrates the two-way nature of the interplay between these fields by focusing on a few selected topics. In the next section the author reviews the standard cosmology, especially concentrating on primordial nucleosynthesis and discusses how the standard cosmology has been used to place constraints on the properties of various particles. Grand Unification makes two striking predictions: (i) B non-conservation; (ii) the existence of stable, superheavy magnetic monopoles. Both have had great cosmological impact. In the following section the author discusses baryogenesis, the very attractive scenario in which the B,C,CP violating interactions in GUTs provide a dynamical explanation for the predominance of matter over antimatter and the present baryon-to-photon ratio. Monopoles are a cosmological disaster and an astrophysicist's delight. In Section 4 discusses monopoles, cosmology, and astrophysics. In the fourth lecture the author discusses how a very early (t≤10/sup -34/ sec) phase transition associated with spontaneous symmetry breaking (SSB) has the potential to explain a handful of very fundamental cosmological facts, facts which can be accommodated by the standard cosmology, but which are not ''explained'' by it. The fifth lecture is devoted to a discussion of structure formation in the universe
Lifts of projective congruence groups, II
DEFF Research Database (Denmark)
Kiming, Ian
2014-01-01
We continue and complete our previous paper ``Lifts of projective congruence groups'' concerning the question of whether there exist noncongruence subgroups of that are projectively equivalent to one of the groups or . A complete answer to this question is obtained: In case of such noncongruence...
Sears Point Tidal Marsh Restoration Project: Phase II
Information about the SFBWQP Sears Point Tidal Marsh Restoration Project: Phase II, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.
LHC related projects and studies - Part (II)
International Nuclear Information System (INIS)
Rossi, L.; De Maria, R.
2012-01-01
The session was devoted to address some aspects of the HL-LHC (High Luminosity LHC) project and explore ideas on new machines for the long term future. The session had two parts. The former focused on some of the key issues of the HL-LHC projects: beam current limits, evolution of the collimation system, research plans for the interaction region magnets and crab cavities. The latter explored the ideas for the long term future projects (LHeC and HE-LHC) and how the current research-development program for magnets and RF structures could fit in the envisaged scenarios
International Nuclear Information System (INIS)
Landsberg, P.T.; Evans, D.A.
1977-01-01
The subject is dealt with in chapters, entitled: cosmology -some fundamentals; Newtonian gravitation - some fundamentals; the cosmological differential equation - the particle model and the continuum model; some simple Friedmann models; the classification of the Friedmann models; the steady-state model; universe with pressure; optical effects of the expansion according to various theories of light; optical observations and cosmological models. (U.K.)
Observable cosmology and cosmological models
International Nuclear Information System (INIS)
Kardashev, N.S.; Lukash, V.N.; Novikov, I.D.
1987-01-01
Modern state of observation cosmology is briefly discussed. Among other things, a problem, related to Hibble constant and slowdown constant determining is considered. Within ''pancake'' theory hot (neutrino) cosmological model explains well the large-scale structure of the Universe, but does not explain the galaxy formation. A cold cosmological model explains well light object formation, but contradicts data on large-scale structure
Zhang Yuan Zhong
2002-01-01
This book is one of a series in the areas of high-energy physics, cosmology and gravitation published by the Institute of Physics. It includes courses given at a doctoral school on 'Relativistic Cosmology: Theory and Observation' held in Spring 2000 at the Centre for Scientific Culture 'Alessandro Volta', Italy, sponsored by SIGRAV-Societa Italiana di Relativita e Gravitazione (Italian Society of Relativity and Gravitation) and the University of Insubria. This book collects 15 review reports given by a number of outstanding scientists. They touch upon the main aspects of modern cosmology from observational matters to theoretical models, such as cosmological models, the early universe, dark matter and dark energy, modern observational cosmology, cosmic microwave background, gravitational lensing, and numerical simulations in cosmology. In particular, the introduction to the basics of cosmology includes the basic equations, covariant and tetrad descriptions, Friedmann models, observation and horizons, etc. The ...
EBR-II and TREAT Digitization Project
Energy Technology Data Exchange (ETDEWEB)
Griffith, George W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-09-01
Digitizing the technical drawings for EBR-II and TREAT provides multiple benefits. Moving the scanned or hard copy drawings to modern 3-D CAD (Computer Aided Drawing) format saves data that could be lost over time. The 3-D drawings produce models that can interface with other drawings to make complex assemblies. The 3-D CAD format can also include detailed material properties and parametric coding that can tie critical dimensions together allowing easier modification. Creating the new files from the old drawings has found multiple inconsistencies that are being flagged or corrected improving understanding of the reactor(s).
EBR-II and TREAT Digitization Project
International Nuclear Information System (INIS)
Griffith, George W.; Rabiti, Cristian
2015-01-01
Digitizing the technical drawings for EBR-II and TREAT provides multiple benefits. Moving the scanned or hard copy drawings to modern 3-D CAD (Computer Aided Drawing) format saves data that could be lost over time. The 3-D drawings produce models that can interface with other drawings to make complex assemblies. The 3-D CAD format can also include detailed material properties and parametric coding that can tie critical dimensions together allowing easier modification. Creating the new files from the old drawings has found multiple inconsistencies that are being flagged or corrected improving understanding of the reactor(s).
International Nuclear Information System (INIS)
Hemmie, G.
1987-01-01
DESY II has been extensively tested at low magnet current excitations corresponding to 1 GeV maximum energy. After the old DESY I synchrotron was turned off in Nov. 86 the provisional power supplies were replaced by magnet- and rf-power supplies of full 8 GeV rating. All external beam lines have now been connected to the new machine. Some modifications on components are described. A report on the results from the initial tests of the machine under full power conditions is given
Directory of Open Access Journals (Sweden)
Ćirković M.M.
1998-01-01
Full Text Available In this work we expand the previous discussion of the plausibility of hypothesis of origin of the Lyα forest absorption systems in haloes of normal galaxies in connection with the HubbleDeepField (HDF data. It is shown that simplistic approach to absorption cross-sections of galaxies with no luminosity scaling is in strong violation of empirical statistics up to redshift of z ∼ 3.5. Realistic variation of the covering factor in order to account for its increase in the inner parts of observed haloes leads to even bigger discrepancy. Cosmologies with finite cosmological constant are briefly discussed and compared to Λ = 0 case. Ways to improve agreement with observational data are indicated. This problem is highly illustrative of the basic tenets of modern observational cosmology.
TA 55 Reinvestment Project II Phase C Update Project Status May 23, 2017
Energy Technology Data Exchange (ETDEWEB)
Giordano, Anthony P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-05-25
The TA-55 Reinvestment Project (TRP) II Phase C is a critical infrastructure project focused on improving safety and reliability of the Los Alamos National Laboratory (LANL) TA-55 Complex. The Project recapitalizes and revitalizes aging and obsolete facility and safety systems providing a sustainable nuclear facility for National Security Missions.
Project management at Heysham II and Torness
International Nuclear Information System (INIS)
Taylor, D.
1987-01-01
The National Nuclear Corporation (NNC) have contracts from the Central Electricity Generating Board (CEGB) and the South of Scotland Electricity Board (SSEB) for the design and construction of the AGR Nuclear Power Stations at Heysham II and Torness. Within these contracts, procurement and construction of the various components making up the Nuclear Island are managed by NNC as agents of the two generating boards. Other responsibilities are for the design of the whole station, preparation of the safety case and on-site management of the Nuclear Island at both stations. Additional responsibilities are included in the Torness contract such that NNC manage almost the whole of the site works. Construction of both stations started in August 1980 and power raising is expected to commence on time at the end of this year. Both stations are close to the original budget. This paper examines factors which have contributed to this success including the relationship between NNC, the contractors, clients and the safety authority. (author)
Brazilian Decimetric Array (BDA) project - Phase II
Faria, C.; Stephany, S.; Sawant, H. S.; Cecatto, J. R.; Fernandes, F. C. R.
2010-02-01
The configuration of the second phase of the Brazilian Decimetric Array (BDA), installed at Cachoeira Paulista, Brazil (Longitude 45° 0‧ 20″ W and Latitude 22° 41‧ 19″ S), is a T-shaped array where 21 antennas are being added to existing 5 antennas of the first phase. In the third phase, in each arm of the T array, four more antennas will be added and baselines will be increased to 2.5 × 1.25 km in east-west and south directions, respectively. The antennas will be equally spaced at the distances of 250 meters from the central antenna of the T-array. Also, the frequency range will be increased to 1.2-1.7, 2.8 and 5.6 GHz. The Second phase of the BDA should be operational by the middle of 2010 and will operate in the frequency range of (1.2-1.7) GHz for solar and non solar observations. Here, we present the characteristics of the second phase of the BDA project, details of the array configuration, the u-v coverage, the synthesized beam obtained for the proposed configuration.
A status report on the PBFA II construction project
International Nuclear Information System (INIS)
Barr, G.W.; Furaus, J.P.; Cook, D.L.; Shirley, C.G.
1985-01-01
The Particle Beam Fusion Accelerator II (PBFA II) is under construction at Sandia National Laboratories (SNL). PBFA II contains 36 individual power modules configured in a stacked radial geometry and synchronized to provide greater than 3.5 MJ of energy into the vacuum section in a single 55-ns-wide 90-TW peak power pulse. This R and D construction project is being implemented in a fast track schedule mode in which final design of the accelerator components occurs in parallel with the construction of the laboratory building and the accelerator tank. PBFA II is scheduled to become operational in January 1986 with its first multi-module shot into an applied-B ion diode that will generate and transport a beam of lithium ions. Plans are now being made for experimental work on PBFA II beyond the construction phase
Sanders, RH; Papantonopoulos, E
2005-01-01
I discuss the classical cosmological tests, i.e., angular size-redshift, flux-redshift, and galaxy number counts, in the light of the cosmology prescribed by the interpretation of the CMB anisotropies. The discussion is somewhat of a primer for physicists, with emphasis upon the possible systematic
International Nuclear Information System (INIS)
Portugal, R.
1984-01-01
Three processes of solutions of the Einstein-Maxwell equations for Bianchi - I, II, VIII, IX and Kantowski-Sachs-like cosmological models with perfect fluid in magnetohydrolodynamical regimem are presented. Diagonal Bianchi-like models are considered with two anisotropy direction in the maximum. Solutions are found for Bianchi-II and IX-like models with energy conditions to be analyzed. Solutions are found for Bianchi-IX and Kantowski-Sachs-Like models with positive electric conductivity and satisfering to the predominant energy conditions. Solutions are formed for isotropic Kantowski-Sachs-Like models satisfering to the equation of state p=λρ, 0 0, admiting, in addition to the perfect fluid, electric field only. It is shown that a class of Bertotti-Robinson-like solutions is unstable by perturbations and it is carried in Kantowski-Sachs-like models with non-null electric conductivity. (L.C.) [pt
A ProCoS II Project Final Report: ESPRIT Basic Research project 707
DEFF Research Database (Denmark)
Bowen, J. P.; Hoare, C. A. R.; Langmaack, Hans
1996-01-01
An overview of the research and associated activities of the Europeancollaborative ESPRIT Basic Research ProCoS II project (no. 7071) on``Provably Correct Systems'' which ran from 1992 to 1995 is presented.This was a follow-on project to ProCoS (no. 3104) and ran inparallel with the ProCoS Working...
Cosmological models without singularities
International Nuclear Information System (INIS)
Petry, W.
1981-01-01
A previously studied theory of gravitation in flat space-time is applied to homogeneous and isotropic cosmological models. There exist two different classes of models without singularities: (i) ever-expanding models, (ii) oscillating models. The first class contains models with hot big bang. For these models there exist at the beginning of the universe-in contrast to Einstein's theory-very high but finite densities of matter and radiation with a big bang of very short duration. After short time these models pass into the homogeneous and isotropic models of Einstein's theory with spatial curvature equal to zero and cosmological constant ALPHA >= O. (author)
International Nuclear Information System (INIS)
Kuo, C. Y.; Braatz, J. A.; Condon, J. J.; Impellizzeri, C. M. V.; Lo, K. Y.; Zaw, I.; Schenker, M.; Henkel, C.; Reid, M. J.; Greene, J. E.
2011-01-01
Observations of H 2 O masers from circumnuclear disks in active galaxies for the Megamaser Cosmology Project (MCP) allow accurate measurement of the mass of supermassive black holes (BH) in these galaxies. We present the Very Long Baseline Interferometry images and kinematics of water maser emission in six active galaxies: NGC 1194, NGC 2273, NGC 2960 (Mrk 1419), NGC 4388, NGC 6264 and NGC 6323. We use the Keplerian rotation curves of these six megamaser galaxies, plus a seventh previously published, to determine accurate enclosed masses within the central ∼0.3 pc of these galaxies, smaller than the radius of the sphere of influence of the central mass in all cases. We also set lower limits to the central mass densities of between 0.12 x 10 10 and 61 x 10 10 M sun pc -3 . For six of the seven disks, the high central densities rule out clusters of stars or stellar remnants as the central objects, and this result further supports our assumption that the enclosed mass can be attributed predominantly to a supermassive BH. The seven BHs have masses ranging between 0.75 x 10 7 and 6.5 x 10 7 M sun , with the mass errors dominated by the uncertainty of the Hubble constant. We compare the megamaser BH mass determination with BH mass measured from the virial estimation method. The virial estimation BH mass in four galaxies is consistent with the megamaser BH mass, but the virial mass uncertainty is much greater. Circumnuclear megamaser disks allow the best mass determination of the central BH mass in external galaxies and significantly improve the observational basis at the low-mass end of the M-σ * relation. The M-σ * relation may not be a single, low-scatter power law as originally proposed. MCP observations continue and we expect to obtain more maser BH masses in the future.
Belinski, Vladimir
2018-01-01
Written for researchers focusing on general relativity, supergravity, and cosmology, this is a self-contained exposition of the structure of the cosmological singularity in generic solutions of the Einstein equations, and an up-to-date mathematical derivation of the theory underlying the Belinski–Khalatnikov–Lifshitz (BKL) conjecture on this field. Part I provides a comprehensive review of the theory underlying the BKL conjecture. The generic asymptotic behavior near the cosmological singularity of the gravitational field, and fields describing other kinds of matter, is explained in detail. Part II focuses on the billiard reformulation of the BKL behavior. Taking a general approach, this section does not assume any simplifying symmetry conditions and applies to theories involving a range of matter fields and space-time dimensions, including supergravities. Overall, this book will equip theoretical and mathematical physicists with the theoretical fundamentals of the Big Bang, Big Crunch, Black Hole singula...
International Nuclear Information System (INIS)
Leibundgut, B.
2005-01-01
Supernovae have developed into a versatile tool for cosmology. Their impact on the cosmological model has been profound and led to the discovery of the accelerated expansion. The current status of the cosmological model as perceived through supernova observations will be presented. Supernovae are currently the only astrophysical objects that can measure the dynamics of the cosmic expansion during the past eight billion years. Ongoing experiments are trying to determine the characteristics of the accelerated expansion and give insight into what might be the physical explanation for the acceleration. (author)
International Nuclear Information System (INIS)
Berstein, J.
1984-01-01
These lectures offer a self-contained review of the role of neutrinos in cosmology. The first part deals with the question 'What is a neutrino.' and describes in a historical context the theoretical ideas and experimental discoveries related to the different types of neutrinos and their properties. The basic differences between the Dirac neutrino and the Majorana neutrino are pointed out and the evidence for different neutrino 'flavours', neutrino mass, and neutrino oscillations is discussed. The second part summarizes current views on cosmology, particularly as they are affected by recent theoretical and experimental advances in high-energy particle physics. Finally, the close relationship between neutrino physics and cosmology is brought out in more detail, to show how cosmological constraints can limit the various theoretical possibilities for neutrinos and, more particularly, how increasing knowledge of neutrino properties can contribute to our understanding of the origin, history, and future of the Universe. The level is that of the beginning graduate student. (orig.)
International Nuclear Information System (INIS)
Khalatnikov, I.M.; Belinskij, V.A.
1984-01-01
Application of the qualitative theory of dynamic systems to analysis of homogeneous cosmological models is described. Together with the well-known cases, requiring ideal liquid, the properties of cosmological evolution of matter with dissipative processes due to viscosity are considered. New cosmological effects occur, when viscosity terms being one and the same order with the rest terms in the equations of gravitation or even exceeding them. In these cases the description of the dissipative process by means of only two viscosity coefficients (volume and shift) may become inapplicable because all the rest decomposition terms of dissipative addition to the energy-momentum in velocity gradient can be large application of equations with hydrodynamic viscosty should be considered as a model of dissipative effects in cosmology
Lesgourgues, Julien; Miele, Gennaro; Pastor, Sergio
2013-01-01
The role that neutrinos have played in the evolution of the Universe is the focus of one of the most fascinating research areas that has stemmed from the interplay between cosmology, astrophysics and particle physics. In this self-contained book, the authors bring together all aspects of the role of neutrinos in cosmology, spanning from leptogenesis to primordial nucleosynthesis, their role in CMB and structure formation, to the problem of their direct detection. The book starts by guiding the reader through aspects of fundamental neutrino physics, such as the standard cosmological model and the statistical mechanics in the expanding Universe, before discussing the history of neutrinos in chronological order from the very early stages until today. This timely book will interest graduate students and researchers in astrophysics, cosmology and particle physics, who work with either a theoretical or experimental focus.
International Nuclear Information System (INIS)
Zeldovich, Y.B.
1983-01-01
This paper fives a general review of modern cosmology. The following subjects are discussed: hot big bang and periodization of the evolution; Hubble expansion; the structure of the universe (pancake theory); baryon asymmetry; inflatory universe. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Zhang Yuanzhong
2002-06-21
This book is one of a series in the areas of high-energy physics, cosmology and gravitation published by the Institute of Physics. It includes courses given at a doctoral school on 'Relativistic Cosmology: Theory and Observation' held in Spring 2000 at the Centre for Scientific Culture 'Alessandro Volta', Italy, sponsored by SIGRAV-Societa Italiana di Relativita e Gravitazione (Italian Society of Relativity and Gravitation) and the University of Insubria. This book collects 15 review reports given by a number of outstanding scientists. They touch upon the main aspects of modern cosmology from observational matters to theoretical models, such as cosmological models, the early universe, dark matter and dark energy, modern observational cosmology, cosmic microwave background, gravitational lensing, and numerical simulations in cosmology. In particular, the introduction to the basics of cosmology includes the basic equations, covariant and tetrad descriptions, Friedmann models, observation and horizons, etc. The chapters on the early universe involve inflationary theories, particle physics in the early universe, and the creation of matter in the universe. The chapters on dark matter (DM) deal with experimental evidence of DM, neutrino oscillations, DM candidates in supersymmetry models and supergravity, structure formation in the universe, dark-matter search with innovative techniques, and dark energy (cosmological constant), etc. The chapters about structure in the universe consist of the basis for structure formation, quantifying large-scale structure, cosmic background fluctuation, galaxy space distribution, and the clustering of galaxies. In the field of modern observational cosmology, galaxy surveys and cluster surveys are given. The chapter on gravitational lensing describes the lens basics and models, galactic microlensing and galaxy clusters as lenses. The last chapter, 'Numerical simulations in cosmology', deals with spatial and
Diemer, Benedikt; Mansfield, Philip; Kravtsov, Andrey V.; More, Surhud
2017-07-01
The splashback radius R sp, the apocentric radius of particles on their first orbit after falling into a dark matter halo, has recently been suggested to be a physically motivated halo boundary that separates accreting from orbiting material. Using the Sparta code presented in Paper I, we analyze the orbits of billions of particles in cosmological simulations of structure formation and measure R sp for a large sample of halos that span a mass range from dwarf galaxy to massive cluster halos, reach redshift 8, and include WMAP, Planck, and self-similar cosmologies. We analyze the dependence of R sp/R 200m and M sp/M 200m on the mass accretion rate Γ, halo mass, redshift, and cosmology. The scatter in these relations varies between 0.02 and 0.1 dex. While we confirm the known trend that R sp/R 200m decreases with Γ, the relationships turn out to be more complex than previously thought, demonstrating that R sp is an independent definition of the halo boundary that cannot trivially be reconstructed from spherical overdensity definitions. We present fitting functions for R sp/R 200m and M sp/M 200m as a function of accretion rate, peak height, and redshift, achieving an accuracy of 5% or better everywhere in the parameter space explored. We discuss the physical meaning of the distribution of particle apocenters and show that the previously proposed definition of R sp as the radius of the steepest logarithmic density slope encloses roughly three-quarters of the apocenters. Finally, we conclude that no analytical model presented thus far can fully explain our results.
International Nuclear Information System (INIS)
Zeldovich, Ya.
1984-01-01
The knowledge is summed up of contemporary cosmology on the universe and its development resulting from a great number of highly sensitive observations and the application of contemporary physical theories to the entire universe. The questions are assessed of mass density in the universe, the structure and origin of the universe, its baryon asymmetry and the quantum explanation of the origin of the universe. Physical problems are presented which should be resolved for the future development of cosmology. (Ha)
CERN. Geneva
2007-01-01
The understanding of the Universe at the largest and smallest scales traditionally has been the subject of cosmology and particle physics, respectively. Studying the evolution of the Universe connects today's large scales with the tiny scales in the very early Universe and provides the link between the physics of particles and of the cosmos. This series of five lectures aims at a modern and critical presentation of the basic ideas, methods, models and observations in today's particle cosmology.
Report on the state of research in the 5-dimensional projective unified field theory
International Nuclear Information System (INIS)
Schmutzer, Ernst
2009-01-01
The author presents a historical sketch of the projective relativity theory before and (with new qualitative arguments) after World War II. Then he treats the development of his Projective Unified Field Theory since 1957 up till now with applications to a closed cosmological model, with the result of a vanishing big bang and satisfying numerical cosmological parameters in good agreement with the experiments. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Truslow, E. C.; Smith, R. C.
1961-12-01
THESE TWO VOLUMES CONSTITUTE A RECORD OF THE TECHNICAL, ADMINISTRATIVE , AND POLICY-MAKING ACTIVITIES OF THE LOS ALAMOS PROJECT (PROJECT Y) FROM ITS INCEPTION UNDER THE MANHATTAN DISTRICT THROUGH THE DEVELOPMENT OF THE ATOMIC BOMB (VOL. I), AND DURING THE PERIOD FOLLOWING THE END OF WORLD WAR II UNTIL THE MANHATTAN DISTRICT RELINQUISHED CONTROL TO THE ATOMIC ENERGY COMMISSION AS OF JANUARY 1947 (VOL. II). ALTHOUGH SEC URITY REGULATIONS HAVE REQUIRED SOME DELETIONS IN THE ORIGINAL TEXT OF THE TWO VOLUMES, EVERY EFFORT HAS BEEN MADE TO RETAIN THE ORIGINAL LANGUGAGE AND EXPERSSIONS OF THE AUTHORS.
Rajantie, Arttu
2018-03-06
The discovery of the Higgs boson in 2012 and other results from the Large Hadron Collider have confirmed the standard model of particle physics as the correct theory of elementary particles and their interactions up to energies of several TeV. Remarkably, the theory may even remain valid all the way to the Planck scale of quantum gravity, and therefore it provides a solid theoretical basis for describing the early Universe. Furthermore, the Higgs field itself has unique properties that may have allowed it to play a central role in the evolution of the Universe, from inflation to cosmological phase transitions and the origin of both baryonic and dark matter, and possibly to determine its ultimate fate through the electroweak vacuum instability. These connections between particle physics and cosmology have given rise to a new and growing field of Higgs cosmology, which promises to shed new light on some of the most puzzling questions about the Universe as new data from particle physics experiments and cosmological observations become available.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).
International Nuclear Information System (INIS)
Wesson, P.S.
1979-01-01
The Cosmological Principle states: the universe looks the same to all observers regardless of where they are located. To most astronomers today the Cosmological Principle means the universe looks the same to all observers because density of the galaxies is the same in all places. A new Cosmological Principle is proposed. It is called the Dimensional Cosmological Principle. It uses the properties of matter in the universe: density (rho), pressure (p), and mass (m) within some region of space of length (l). The laws of physics require incorporation of constants for gravity (G) and the speed of light (C). After combining the six parameters into dimensionless numbers, the best choices are: 8πGl 2 rho/c 2 , 8πGl 2 rho/c 4 , and 2 Gm/c 2 l (the Schwarzchild factor). The Dimensional Cosmological Principal came about because old ideas conflicted with the rapidly-growing body of observational evidence indicating that galaxies in the universe have a clumpy rather than uniform distribution
Rajantie, Arttu
2018-01-01
The discovery of the Higgs boson in 2012 and other results from the Large Hadron Collider have confirmed the standard model of particle physics as the correct theory of elementary particles and their interactions up to energies of several TeV. Remarkably, the theory may even remain valid all the way to the Planck scale of quantum gravity, and therefore it provides a solid theoretical basis for describing the early Universe. Furthermore, the Higgs field itself has unique properties that may have allowed it to play a central role in the evolution of the Universe, from inflation to cosmological phase transitions and the origin of both baryonic and dark matter, and possibly to determine its ultimate fate through the electroweak vacuum instability. These connections between particle physics and cosmology have given rise to a new and growing field of Higgs cosmology, which promises to shed new light on some of the most puzzling questions about the Universe as new data from particle physics experiments and cosmological observations become available. This article is part of the Theo Murphy meeting issue `Higgs cosmology'.
Energy Technology Data Exchange (ETDEWEB)
Fang, Xiao; Blazek, Jonathan A.; McEwen, Joseph E.; Hirata, Christopher M., E-mail: fang.307@osu.edu, E-mail: blazek@berkeley.edu, E-mail: mcewen.24@osu.edu, E-mail: hirata.10@osu.edu [Center for Cosmology and AstroParticle Physics, Department of Physics, The Ohio State University, 191 W Woodruff Ave, Columbus OH 43210 (United States)
2017-02-01
Cosmological perturbation theory is a powerful tool to predict the statistics of large-scale structure in the weakly non-linear regime, but even at 1-loop order it results in computationally expensive mode-coupling integrals. Here we present a fast algorithm for computing 1-loop power spectra of quantities that depend on the observer's orientation, thereby generalizing the FAST-PT framework (McEwen et al., 2016) that was originally developed for scalars such as the matter density. This algorithm works for an arbitrary input power spectrum and substantially reduces the time required for numerical evaluation. We apply the algorithm to four examples: intrinsic alignments of galaxies in the tidal torque model; the Ostriker-Vishniac effect; the secondary CMB polarization due to baryon flows; and the 1-loop matter power spectrum in redshift space. Code implementing this algorithm and these applications is publicly available at https://github.com/JoeMcEwen/FAST-PT.
Sanders, Robert H
2016-01-01
The advent of sensitive high-resolution observations of the cosmic microwave background radiation and their successful interpretation in terms of the standard cosmological model has led to great confidence in this model's reality. The prevailing attitude is that we now understand the Universe and need only work out the details. In this book, Sanders traces the development and successes of Lambda-CDM, and argues that this triumphalism may be premature. The model's two major components, dark energy and dark matter, have the character of the pre-twentieth-century luminiferous aether. While there is astronomical evidence for these hypothetical fluids, their enigmatic properties call into question our assumptions of the universality of locally determined physical law. Sanders explains how modified Newtonian dynamics (MOND) is a significant challenge for cold dark matter. Overall, the message is hopeful: the field of cosmology has not become frozen, and there is much fundamental work ahead for tomorrow's cosmologis...
The PEP-II project-wide database
International Nuclear Information System (INIS)
Chan, A.; Calish, S.; Crane, G.; MacGregor, I.; Meyer, S.; Wong, J.
1995-05-01
The PEP-II Project Database is a tool for monitoring the technical and documentation aspects of this accelerator construction. It holds the PEP-II design specifications, fabrication and installation data in one integrated system. Key pieces of the database include the machine parameter list, magnet and vacuum fabrication data. CAD drawings, publications and documentation, survey and alignment data and property control. The database can be extended to contain information required for the operations phase of the accelerator and detector. Features such as viewing CAD drawing graphics from the database will be implemented in the future. This central Oracle database on a UNIX server is built using ORACLE Case tools. Users at the three collaborating laboratories (SLAC, LBL, LLNL) can access the data remotely, using various desktop computer platforms and graphical interfaces
International Nuclear Information System (INIS)
Dickau, Jonathan J.
2009-01-01
The use of fractals and fractal-like forms to describe or model the universe has had a long and varied history, which begins long before the word fractal was actually coined. Since the introduction of mathematical rigor to the subject of fractals, by Mandelbrot and others, there have been numerous cosmological theories and analyses of astronomical observations which suggest that the universe exhibits fractality or is by nature fractal. In recent years, the term fractal cosmology has come into usage, as a description for those theories and methods of analysis whereby a fractal nature of the cosmos is shown.
The continual fuel management modification in Qinshan project II
International Nuclear Information System (INIS)
Ye Guodong; Pan Zefei; Zhang Xingtian
2010-01-01
The fuel management strategy is the basis of the nuclear power plants. The performance of the fuel management strategy affects the plants' safety and economy indicators directly. The paper summarizes all the modifications on the fuel management work in Qinshan Project II since the plant was established. It includes the surveillance system of physics tests, fetching in high performance fuel assemblies, reloading pattern optimization, and the modifications of the final safety analysis report. At the same time, it evaluates the benefit of the modifications in the few years. The experience in this paper is much helpful and could be implemented on the same type plants. (authors)
Enqvist, K
2012-01-01
The very basics of cosmological inflation are discussed. We derive the equations of motion for the inflaton field, introduce the slow-roll parameters, and present the computation of the inflationary perturbations and their connection to the temperature fluctuations of the cosmic microwave background.
Ellis, G F R
1993-01-01
Many topics were covered in the submitted papers, showing much life in this subject at present. They ranged from conventional calculations in specific cosmological models to provocatively speculative work. Space and time restrictions required selecting from them, for summarisation here; the book of Abstracts should be consulted for a full overview.
International Nuclear Information System (INIS)
Chow, Nathan; Khoury, Justin
2009-01-01
We study the cosmology of a galileon scalar-tensor theory, obtained by covariantizing the decoupling Lagrangian of the Dvali-Gabadadze-Poratti (DGP) model. Despite being local in 3+1 dimensions, the resulting cosmological evolution is remarkably similar to that of the full 4+1-dimensional DGP framework, both for the expansion history and the evolution of density perturbations. As in the DGP model, the covariant galileon theory yields two branches of solutions, depending on the sign of the galileon velocity. Perturbations are stable on one branch and ghostlike on the other. An interesting effect uncovered in our analysis is a cosmological version of the Vainshtein screening mechanism: at early times, the galileon dynamics are dominated by self-interaction terms, resulting in its energy density being suppressed compared to matter or radiation; once the matter density has redshifted sufficiently, the galileon becomes an important component of the energy density and contributes to dark energy. We estimate conservatively that the resulting expansion history is consistent with the observed late-time cosmology, provided that the scale of modification satisfies r c > or approx. 15 Gpc.
Test Plan for Hydrogen Getters Project - Phase II
International Nuclear Information System (INIS)
Mroz, G.
1999-01-01
Hydrogen levels in many transuranic (TRU) waste drums are above the compliance threshold, therefore deeming the drums non-shippable to the Waste Isolation Pilot Plant (WIPP). Hydrogen getters (alkynes and dialkynes) are known to react irreversibly with hydrogen in the presence of certain catalysts. The primary purpose of this investigation is to ascertain the effectiveness of a hydrogen getter in an environment that contains gaseous compounds commonly found in the headspace of drums containing TRU waste. It is not known whether the volatile organic compounds (VOCs) commonly found in the headspace of TRU waste drums will inhibit (''poison'') the effectiveness of the hydrogen getter. The result of this study will be used to assess the feasibility of a hydrogen-getter system, which is capable of removing hydrogen from the payload containers or the Transuranic Package Transporter-II (TRUPACT-II) inner containment vessel to increase the quantity of TRU waste that can be shipped to the WIPP. Phase II for the Hydrogen Getters Project will focus on four primary objectives: Conduct measurements of the relative permeability of hydrogen and chlorinated VOCs through Tedlar (and possibly other candidate packaging materials) Test alternative getter systems as alternatives to semi-permeable packaging materials. Candidates include DEB/Pd/Al2O3 and DEB/Cu-Pd/C. Develop, test, and deploy kinetic optimization model Perform drum-scale test experiments to demonstrate getter effectiveness
DECOVALEX II PROJECT Technical Report - Task 2C
International Nuclear Information System (INIS)
Jing, L.; Stephansson, O.; Chijimatzu, M.; Tsang, C.F.
1999-05-01
The DECOVALEX II project is an international co-operative research project supported by a number of national radioactive waste management organizations of different countries. The project studied four tasks: Task 1: numerical simulation of the RCF3 pump test at Sellafield, UK; Task 2: numerical simulation of the in situ T-H-M experiment at Kamaishi Mine, Japan; Task 3: monitoring of current development in rock fracture research; and Task 4: report on treatment of T-H-M processes in Performance Assessment works for nuclear waste repositories. The project started in 1995 and is scheduled to be finalised in March, 1999. This report concerns the Task 2 of the DECOVALEX H project. Task 2 of the DECOVALEX II project is the numerical modelling of the in-situ T-H-M experiment of a fractured rock - buffer - heater system at Kamaishi Mine, Japan. The experiment was carried out inside a test pit drilled in the floor of a 5 x 7 m alcove excavated near an existing drift at the 550 m level. The test pit has a circular cross section of diameter 1.7 m and a depth of 5 m, filled with bentonite which contains an electric heater. Four research teams studied Task 2 with different computational models. The task is divided into three sub-tasks: Task 2A, Task 2B and Task 2C. Task 2A was defined as a blind prediction to the coupled hydro-mechanical behaviour of the fractured rocks due to the excavation of the test pit. The calibration of the numerical models against measured results of pore pressures, flow rates and rock deformation before filling up of the test pit formed Task 2B. These two sub-tasks were performed to establish well calibrated fields of hydraulic conductivity and mechanical deformability of the fractured rocks at the test site. They were necessary for further simulations on interactions between the rock and buffer materials during heating experiments, as required for Task 2C, with a higher level of confidence on rock mass models. Presented in this report is the
DECOVALEX II PROJECT Technical Report - Task 2C
Energy Technology Data Exchange (ETDEWEB)
Jing, L.; Stephansson, O. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Civil and Environmental Engineering; Boergesson, L. [Clay Technology AB, IDEON Research Center, Lund (Sweden); Chijimatzu, M. [Japan Nuclear Cycle Development Inst., Ibaraki (Japan). Waste Management and Fuel Cycle Research Center; Kautsky, F. [Swedish Nuclear Power Inspectorate (SKI), Stockholm (Sweden); Tsang, C.F. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Earth Science Div.
1999-05-01
The DECOVALEX II project is an international co-operative research project supported by a number of national radioactive waste management organizations of different countries. The project studied four tasks: Task 1: numerical simulation of the RCF3 pump test at Sellafield, UK; Task 2: numerical simulation of the in situ T-H-M experiment at Kamaishi Mine, Japan; Task 3: monitoring of current development in rock fracture research; and Task 4: report on treatment ofT-H-M processes in Performance Assessment works for nuclear waste repositories. The project started in 1995 and is scheduled to be finalised in March, 1999. This report concerns the Task 2 of the DECOVALEX H project. Task 2 of the DECOVALEX II project is the numerical modelling of the in-situ T-H-M experiment of a fractured rock - buffer - heater system at Kamaishi Mine, Japan. The experiment was carried out inside a test pit drilled in the floor of a 5 x 7 m alcove excavated near an existing drift at the 550 m level. The test pit has a circular cross section of diameter 1.7 m and a depth of 5 m, filled with bentonite which contains an electric heater. Four research teams studied Task 2 with different computational models. The task is divided into three sub-tasks: Task 2A, Task 2B and Task 2C. Task 2A was defined as a blind prediction to the coupled hydro-mechanical behaviour of the fractured rocks due to the excavation of the test pit. The calibration of the numerical models against measured results of pore pressures, flow rates and rock deformation before filling up of the test pit formed Task 2B. These two sub-tasks were performed to establish well calibrated fields of hydraulic conductivity and mechanical deformability of the fractured rocks at the test site. They were necessary for further simulations on interactions between the rock and buffer materials during heating experiments, as required for Task 2C, with a higher level of confidence on rock mass models. Presented in this report is the definition
Grant, E.; Murdin, P.
2000-11-01
During the early Middle Ages (ca 500 to ca 1130) scholars with an interest in cosmology had little useful and dependable literature. They relied heavily on a partial Latin translation of PLATO's Timaeus by Chalcidius (4th century AD), and on a series of encyclopedic treatises associated with the names of Pliny the Elder (ca AD 23-79), Seneca (4 BC-AD 65), Macrobius (fl 5th century AD), Martianus ...
International Nuclear Information System (INIS)
Partridge, R.B.
1977-01-01
Some sixty years after the development of relativistic cosmology by Einstein and his colleagues, observations are finally beginning to have an important impact on our views of the Universe. The available evidence seems to support one of the simplest cosmological models, the hot Big Bang model. The aim of this paper is to assess the observational support for certain assumptions underlying the hot Big Bang model. These are that the Universe is isobaric and homogeneous on a large scale; that it is expanding from an initial state of high density and temperature; and that the proper theory to describe the dynamics of the Universe is unmodified General Relativity. The properties of the cosmic microwave background radiation and recent observations of the abundance of light elements, in particular, support these assumptions. Also examined here are the data bearing on the related questions of the geometry and the future of the Universe (is it ever-expanding, or fated to recollapse). Finally, some difficulties and faults of the standard model are discussed, particularly various aspects of the 'initial condition' problem. It appears that the simplest Big Bang cosmological model calls for a highly specific set of initial conditions to produce the presently observed properties of the Universe. (Auth.)
the Universe About Cosmology Planck Satellite Launched Cosmology Videos Professor George Smoot's group conducts research on the early universe (cosmology) using the Cosmic Microwave Background radiation (CMB science goals regarding cosmology. George Smoot named Director of Korean Cosmology Institute The GRB
Emission projections 2008-2012 versus national allocation plans II
International Nuclear Information System (INIS)
Neuhoff, Karsten; Ferrario, Federico; Grubb, Michael; Gabel, Etienne; Keats, Kim
2006-01-01
We compare the national allocation plans (NAPs), proposed and submitted by EU Member States as of October 2006, with our estimations for CO 2 emissions by the installations covered by these NAPs. The collective allocations proposed under phase II NAPs exceed the historic trend of emissions extrapolated forward. Using our projections we find, depending on uncertainty in fuel prices, economic growth rates, performance of the non-power sector and CDM/JI availability, a 15% chance of a 'dead market' with emissions below cap even at zero prices. With an expected inflow of committed CDM/JI credits of 100 MtCO 2 /year, allowance supply will exceed demand in 50% of cases without any carbon price, and in 80% of our euros20/tCO 2 scenarios. Banking of allowances towards post-2012 conditions could create additional demand, but this is difficult to anticipate and conditional on policy evolution. The proposed phase II NAPs would result in low prices and only small volumes of CDM/JI would enter the EU ETS. CDM/JI would almost exclusively be public-sector funded, placing the cost of Kyoto compliance entirely upon governments. (Author)
The PEP-II Project: Low-Energy Ring Design and Project Status
International Nuclear Information System (INIS)
Zisman, Michael S.
2006-01-01
We describe the present status of the PEP-II project. The project comprises four major systems: Injector, High-Energy Ring (HER), Low-Energy Ring (LER), and Interaction Region (IR). We focus in detail on the design of the LER, as its parameters and requirements are most closely related to those required for the Beijing Tau-Charm Factory rings. The PEP-II LER is a high-current, 3.1-GeV positron ring mounted above the 9-GeV HER. The LER uses a wiggler located in one of its six straight sections to provide emittance control and additional damping. We describe the rather complicated IR, which must transport the LER beam into the plane of the HER, focus it to a common beam size, and separate the beams after the head-on collisions. Both permanent magnet and conventional electromagnets are used in this area. The LER lattice has now adopted a simplified non-interleaved sextupole correction scheme that has reduced the required number of sextupoles substantially. We describe the LER vacuum system, one of the most challenging subsystems in PEP-II. It employs several technologies. In the arcs, aluminum extrusions and titanium sublimation pumps are employed; the straight sections use stainless steel chambers with lumped ion pumps. In the wiggler area, an extended copper photon dump with nonevaporable getter (NEG) pumps is employed to handle the very large synchrotron radiation power. The design of the room-temperature RF system, the bunch-by-bunch longitudinal and transverse feedback systems, and some of the special diagnostics will be described briefly. The PEP-II project remains on schedule to begin commissioning of the HER in April 1997, followed by the LER a year later
Dedicated OO expertise applied to Run II software projects
International Nuclear Information System (INIS)
Amidei, D.
2000-01-01
The change in software language and methodology by CDF and D0 to object-oriented from procedural Fortran is significant. Both experiments requested dedicated expertise that could be applied to software design, coding, advice and review. The Fermilab Run II offline computing outside review panel agreed strongly with the request and recommended that the Fermilab Computing Division hire dedicated OO expertise for the CDF/D0/Computing Division joint project effort. This was done and the two experts have been an invaluable addition to the CDF and D0 upgrade software projects and to the Computing Division in general. These experts have encouraged common approaches and increased the overall quality of the upgrade software. Advice on OO techniques and specific advice on C++ coding has been used. Recently a set of software reviews has been accomplished. This has been a very successful instance of a targeted application of computing expertise, and constitutes a very interesting study of how to move toward modern computing methodologies in HEP
Blade System Design Study. Part II, final project report (GEC).
Energy Technology Data Exchange (ETDEWEB)
Griffin, Dayton A. (DNV Global Energy Concepts Inc., Seattle, WA)
2009-05-01
As part of the U.S. Department of Energy's Low Wind Speed Turbine program, Global Energy Concepts LLC (GEC)1 has studied alternative composite materials for wind turbine blades in the multi-megawatt size range. This work in one of the Blade System Design Studies (BSDS) funded through Sandia National Laboratories. The BSDS program was conducted in two phases. In the Part I BSDS, GEC assessed candidate innovations in composite materials, manufacturing processes, and structural configurations. GEC also made recommendations for testing composite coupons, details, assemblies, and blade substructures to be carried out in the Part II study (BSDS-II). The BSDS-II contract period began in May 2003, and testing was initiated in June 2004. The current report summarizes the results from the BSDS-II test program. Composite materials evaluated include carbon fiber in both pre-impregnated and vacuum-assisted resin transfer molding (VARTM) forms. Initial thin-coupon static testing included a wide range of parameters, including variation in manufacturer, fiber tow size, fabric architecture, and resin type. A smaller set of these materials and process types was also evaluated in thin-coupon fatigue testing, and in ply-drop and ply-transition panels. The majority of materials used epoxy resin, with vinyl ester (VE) resin also used for selected cases. Late in the project, testing of unidirectional fiberglass was added to provide an updated baseline against which to evaluate the carbon material performance. Numerous unidirectional carbon fabrics were considered for evaluation with VARTM infusion. All but one fabric style considered suffered either from poor infusibility or waviness of fibers combined with poor compaction. The exception was a triaxial carbon-fiberglass fabric produced by SAERTEX. This fabric became the primary choice for infused articles throughout the test program. The generally positive results obtained in this program for the SAERTEX material have led to its
Brandenberger, Robert H.
2008-01-01
String gas cosmology is a string theory-based approach to early universe cosmology which is based on making use of robust features of string theory such as the existence of new states and new symmetries. A first goal of string gas cosmology is to understand how string theory can effect the earliest moments of cosmology before the effective field theory approach which underlies standard and inflationary cosmology becomes valid. String gas cosmology may also provide an alternative to the curren...
Magnetohydrodynamic cosmologies
International Nuclear Information System (INIS)
Portugal, R.; Soares, I.D.
1991-01-01
We analyse a class of cosmological models in magnetohydrodynamic regime extending and completing the results of a previous paper. The material content of the models is a perfect fluid plus electromagnetic fields. The fluid is neutral in average but admits an electrical current which satisfies Ohm's law. All models fulfil the physical requirements of near equilibrium thermodynamics and can be favourably used as a more realistic description of the interior of a collapsing star in a magnetohydrodynamic regime with or without a magnetic field. (author)
Bardeen, J. M.
The last several years have seen a tremendous ferment of activity in astrophysical cosmology. Much of the theoretical impetus has come from particle physics theories of the early universe and candidates for dark matter, but what promise to be even more significant are improved direct observations of high z galaxies and intergalactic matter, deeper and more comprehensive redshift surveys, and the increasing power of computer simulations of the dynamical evolution of large scale structure. Upper limits on the anisotropy of the microwave background radiation are gradually getting tighter and constraining more severely theoretical scenarios for the evolution of the universe.
International Nuclear Information System (INIS)
Bardeen, J.M.
1986-01-01
The last several years have seen a tremendous ferment of activity in astrophysical cosmology. Much of the theoretical impetus has come from particle physics theories of the early universe and candidates for dark matter, but what promise to be even more significant are improved direct observations of high z galaxies and intergalactic matter, deeper and more comprehensive redshift surveys, and the increasing power of computer simulations of the dynamical evolution of large scale structure. Upper limits on the anisotropy of the microwave background radiation are gradually getting tighter and constraining more severely theoretical scenarios for the evolution of the universe. 47 refs
Page, Don N.
2006-01-01
A complete model of the universe needs at least three parts: (1) a complete set of physical variables and dynamical laws for them, (2) the correct solution of the dynamical laws, and (3) the connection with conscious experience. In quantum cosmology, item (2) is the quantum state of the cosmos. Hartle and Hawking have made the `no-boundary' proposal, that the wavefunction of the universe is given by a path integral over all compact Euclidean 4-dimensional geometries and matter fields that hav...
Religion, theology and cosmology
Directory of Open Access Journals (Sweden)
John T. Fitzgerald
2013-10-01
Full Text Available Cosmology is one of the predominant research areas of the contemporary world. Advances in modern cosmology have prompted renewed interest in the intersections between religion, theology and cosmology. This article, which is intended as a brief introduction to the series of studies on theological cosmology in this journal, identifies three general areas of theological interest stemming from the modern scientific study of cosmology: contemporary theology and ethics; cosmology and world religions; and ancient cosmologies. These intersections raise important questions about the relationship of religion and cosmology, which has recently been addressed by William Scott Green and is the focus of the final portion of the article.
International Nuclear Information System (INIS)
Chimento, L P; Forte, M; Devecchi, F P; Kremer, G M; Ribas, M O; Samojeden, L L
2011-01-01
In this work we review if fermionic sources could be responsible for accelerated periods during the evolution of a FRW universe. In a first attempt, besides the fermionic source, a matter constituent would answer for the decelerated periods. The coupled differential equations that emerge from the field equations are integrated numerically. The self-interaction potential of the fermionic field is considered as a function of the scalar and pseudo-scalar invariants. It is shown that the fermionic field could behave like an inflaton field in the early universe, giving place to a transition to a matter dominated (decelerated) period. In a second formulation we turn our attention to analytical results, specifically using the idea of form-invariance transformations. These transformations can be used for obtaining accelerated cosmologies starting with conventional cosmological models. Here we reconsider the scalar field case and extend the discussion to fermionic fields. Finally we investigate the role of a Dirac field in a Brans-Dicke (BD) context. The results show that this source, in combination with the BD scalar, promote a final eternal accelerated era, after a matter dominated period.
Scalar-tensor cosmology with cosmological constant
International Nuclear Information System (INIS)
Maslanka, K.
1983-01-01
The equations of scalar-tensor theory of gravitation with cosmological constant in the case of homogeneous and isotropic cosmological model can be reduced to dynamical system of three differential equations with unknown functions H=R/R, THETA=phi/phi, S=e/phi. When new variables are introduced the system becomes more symmetrical and cosmological solutions R(t), phi(t), e(t) are found. It is shown that when cosmological constant is introduced large class of solutions which depend also on Dicke-Brans parameter can be obtained. Investigations of these solutions give general limits for cosmological constant and mean density of matter in plane model. (author)
International Nuclear Information System (INIS)
Hawking, S.W.
1984-01-01
The subject of these lectures is quantum effects in cosmology. The author deals first with situations in which the gravitational field can be treated as a classical, unquantized background on which the quantum matter fields propagate. This is the case with inflation at the GUT era. Nevertheless the curvature of spacetime can have important effects on the behaviour of the quantum fields and on the development of long-range correlations. He then turns to the question of the quantization of the gravitational field itself. The plan of these lectures is as follows: Euclidean approach to quantum field theory in flat space; the extension of techniques to quantum fields on a curved background with the four-sphere, the Euclidean version of De Sitter space as a particular example; the GUT era; quantization of the gravitational field by Euclidean path integrals; mini superspace model. (Auth.)
Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S; Rideout, David; Meyer, David; Boguñá, Marián
2012-01-01
Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology.
Narlikar, Jayant Vishnu
2002-01-01
The third edition of this successful textbook is fully updated and includes important recent developments in cosmology. It begins with an introduction to cosmology and general relativity, and goes on to cover the mathematical models of standard cosmology. The physical aspects of cosmology, including primordial nucleosynthesis, the astroparticle physics of inflation, and the current ideas on structure formation are discussed. Alternative models of cosmology are reviewed, including the model of Quasi-Steady State Cosmology, which has recently been proposed as an alternative to Big Bang Cosmology.
International Nuclear Information System (INIS)
Hatch, C.E.
1995-05-01
This document is the Functional Design Criteria for Project W-252. Project W-252 provides the scope to provide BAT/AKART (best available technology...) to 200 Liquid Effluent Phase II streams (B-Plant). This revision (Rev. 2) incorporates a major descoping of the project. The descoping was done to reflect a combination of budget cutting measures allowed by a less stringent regulatory posture toward the Phase II streams
Dimensional cosmological principles
International Nuclear Information System (INIS)
Chi, L.K.
1985-01-01
The dimensional cosmological principles proposed by Wesson require that the density, pressure, and mass of cosmological models be functions of the dimensionless variables which are themselves combinations of the gravitational constant, the speed of light, and the spacetime coordinates. The space coordinate is not the comoving coordinate. In this paper, the dimensional cosmological principle and the dimensional perfect cosmological principle are reformulated by using the comoving coordinate. The dimensional perfect cosmological principle is further modified to allow the possibility that mass creation may occur. Self-similar spacetimes are found to be models obeying the new dimensional cosmological principle
Cosmology and particle physics
International Nuclear Information System (INIS)
Turner, M.S.
1985-01-01
The author reviews the standard cosmology, focusing on primordial nucleosynthesis, and discusses how the standard cosmology has been used to place constraints on the properties of various particles. Baryogenesis is examined in which the B, C, CP violating interactions in GUTs provide a dynamical explanation for the predominance of matter over antimatter and the present baryon-to-baryon ratio. Monoposes, cosmology and astrophysics are reviewed. The author also discusses supersymmetry/supergravity and cosmology, superstrings and cosmology in extra dimensions, and axions, astrophics, and cosmology
FEBEX II Project Post-mortem analysis EDZ assessment
International Nuclear Information System (INIS)
Bazargan Sabet, B.; Shao, H.; Autio, J.; Elorza, F. J.
2004-01-01
Within the framework of the FEBEX II project a multidisciplinary team studied the mechanisms of creation of the potential damaged zone around the test drift. The research program includes laboratory and in situ investigations as well as the numerical modelling of the observed phenomena. Where laboratory investigations are concerned, the 14C-PMMA technique was applied to study the spatial distribution of porosity in the samples taken from the test drift wall. In addition complementary microscopy and scanning electron microscopy (SEM) studies were performed to make qualitative investigations on the pore apertures and minerals in porous regions. The results obtained with the PMMA method have not shown any clear increased porosity zone adjacent to the tunnel wall. The total porosity of the samples varied between 0.6-1.2%. The samples of unplugged region did not differ from the samples of plugged region. A clear increase in porosity to depths of 10-15 mm from the tunnel wall was detected in lamprophyre samples. According to the SEM/EDX analyses the excavation-disturbed zone in the granite matrix extended to depths of 1-3 mm from the wall surface. A few quartz grains were crushed and some micro fractures were found. Gas permeability tests were carried out on two hollow cylinder samples of about 1m long each taken on the granite wall perpendicular to the drift axis. The first sample was cored in the service area far from the heated zone and the second one at the level of the heater. The tests were performed at constant gas pressure by setting a steady state radial flow through a section of 1cm wide isolated by means of four mini-packers. The profile of the gas permeability according to the core length has been established. The results obtained for both considered samples have shown permeability ranging between 3.5 10-18 and 8.4 10-19m2, pointing out the absence of a marked damage. Acoustic investigations have been carried out with the objective of quantifying the
FEBEX II Project Post-mortem analysis EDZ assessment
Energy Technology Data Exchange (ETDEWEB)
Bazargan Sabet, B.; Shao, H.; Autio, J.; Elorza, F. J.
2004-07-01
Within the framework of the FEBEX II project a multidisciplinary team studied the mechanisms of creation of the potential damaged zone around the test drift. The research program includes laboratory and in situ investigations as well as the numerical modelling of the observed phenomena. Where laboratory investigations are concerned, the 14C-PMMA technique was applied to study the spatial distribution of porosity in the samples taken from the test drift wall. In addition complementary microscopy and scanning electron microscopy (SEM) studies were performed to make qualitative investigations on the pore apertures and minerals in porous regions. The results obtained with the PMMA method have not shown any clear increased porosity zone adjacent to the tunnel wall. The total porosity of the samples varied between 0.6-1.2%. The samples of unplugged region did not differ from the samples of plugged region. A clear increase in porosity to depths of 10-15 mm from the tunnel wall was detected in lamprophyre samples. According to the SEM/EDX analyses the excavation-disturbed zone in the granite matrix extended to depths of 1-3 mm from the wall surface. A few quartz grains were crushed and some micro fractures were found. Gas permeability tests were carried out on two hollow cylinder samples of about 1m long each taken on the granite wall perpendicular to the drift axis. The first sample was cored in the service area far from the heated zone and the second one at the level of the heater. The tests were performed at constant gas pressure by setting a steady state radial flow through a section of 1cm wide isolated by means of four mini-packers. The profile of the gas permeability according to the core length has been established. The results obtained for both considered samples have shown permeability ranging between 3.5 10-18 and 8.4 10-19m2, pointing out the absence of a marked damage. Acoustic investigations have been carried out with the objective of quantifying the
A Manhattan Project in Educational Technology, Part II.
Roberts, Wesley K.
The initial four phases of the Training Extension Course (TEC), a project to remedy deficiencies in training programs for armed forces recruits, employed systematic instructional development and extensive audiovisual resources. The project required subcontracting for lesson production and modifications in personnel and budgeting. Posttest evidence…
International Nuclear Information System (INIS)
Gaisser, T.K.; Shafi, Q.; Barr, S.M.; Seckel, D.; Rusjan, E.; Fletcher, R.S.
1991-01-01
This report discusses research of professor at Bartol research institute in the following general areas: particle phenomenology and non-accelerator physics; particle physics and cosmology; theories with higher symmetry; and particle astrophysics and cosmology
International Nuclear Information System (INIS)
Heller, M.
1985-01-01
Two Friedman's cosmological papers (1922, 1924) and his own interpretation of the obtained results are briefly reviewed. Discussion follows of Friedman's role in the early development of relativistic cosmology. 18 refs. (author)
Kunze, Kerstin E.
2016-12-20
Cosmology is becoming an important tool to test particle physics models. We provide an overview of the standard model of cosmology with an emphasis on the observations relevant for testing fundamental physics.
Wind River Watershed Project; 1998 Annual Report; Volume II
International Nuclear Information System (INIS)
Connolly, Patrick J.
1999-01-01
The authors report here their on-ground restoration actions. Part 1 describes work conducted by the Underwood Conservation District (UCD) on private lands. This work involves the Stabler Cut-Bank project. Part 2 describes work conducted by the U.S. Forest Service. The Stabler Cut-Bank Project is a cooperative stream restoration effort between Bonneville Power Administration (BPA), the UCD, private landowners, the U.S. Forest Service (USFS), and the U.S. Fish and Wildlife Service (USFWS). The Stabler site was identified by UCD during stream surveys conducted in 1996 as part of a USFWS funded project aimed at initiating water quality and habitat restoration efforts on private lands in the basin. In 1997 the Wind River Watershed Council selected the project as a top priority demonstration project. The landowners were approached by the UCD and a partnership developed. Due to their expertise in channel rehabilitation, the Forest Service was consulted for the design and assisted with the implementation of the project. A portion of the initial phase of the project was funded by USFWS. However, the majority of funding (approximately 80%) has been provided by BPA and it is anticipated that additional work that is planned for the site will be conducted with BPA funds
Lyth, David
2016-01-01
Written by an award-winning cosmologist, this brand new textbook provides advanced undergraduate and graduate students with coverage of the very latest developments in the observational science of cosmology. The book is separated into three parts; part I covers particle physics and general relativity, part II explores an account of the known history of the universe, and part III studies inflation. Full treatment of the origin of structure, scalar fields, the cosmic microwave background and the early universe are provided. Problems are included in the book with solutions provided in a separate solutions manual. More advanced extension material is offered in the Appendix, ensuring the book is fully accessible to students with a wide variety of background experience.
139 the impact of the national fadama ii development project
African Journals Online (AJOL)
OLUWOLE AKINNAGBE
Key words: Impact, National Fadama II Facility, Poverty Alleviation, Agricultural ... production but enhance the income of the ... of employment has the higher incidence of ... This widening gap between ... each group (i.e. those earning ... Source: Field Survey data, 2007 .... increased as evidence has shown that the level.
Roos, Matts
2015-01-01
The Fourth Edition of Introduction to Cosmology provides a concise, authoritative study of cosmology at an introductory level. Starting from elementary principles and the early history of cosmology, the text carefully guides the student on to curved spacetimes, special and general relativity, gravitational lensing, the thermal history of the Universe, and cosmological models, including extended gravity models, black holes and Hawking's recent conjectures on the not-so-black holes.
Particle physics and cosmology
International Nuclear Information System (INIS)
Turner, M.S.; Schramm, D.N.
1985-01-01
During the past year, the research of the members of our group has spanned virtually all the topics at the interface of cosmology and particle physics: inflationary Universe scenarios, astrophysical and cosmological constraints on particle properties, ultra-high energy cosmic ray physics, quantum field theory in curved space-time, cosmology with extra dimensions, superstring cosmology, neutrino astronomy with large, underground detectors, and the formation of structure in the Universe
Final report on the maintenance asset management project : phase II.
2013-07-01
Iowa Department of Transportation (IA DOT) is finalizing research to streamline field inventory/inspection of culverts by Maintenance and Construction staff while maximizing the use of tablet technologies. The project began in 2011 to develop some ne...
BOOK REVIEW: Black Holes, Cosmology and Extra Dimensions Black Holes, Cosmology and Extra Dimensions
Frolov, Valeri P.
2013-10-01
The book Black holes, Cosmology and Extra Dimensions written by Kirill A Bronnikov and Sergey G Rubin has been published recently by World Scientific Publishing Company. The authors are well known experts in gravity and cosmology. The book is a monograph, a considerable part of which is based on the original work of the authors. Their original point of view on some of the problems makes the book quite interesting, covering a variety of important topics of the modern theory of gravity, astrophysics and cosmology. It consists of 11 chapters which are organized in three parts. The book starts with an introduction, where the authors briefly discuss the main ideas of General Relativity, giving some historical remarks on its development and application to cosmology, and mentioning some more recent subjects such as brane worlds, f(R)-theories and gravity in higher dimensions. Part I of the book is called 'Gravity'. Chapters two and three are devoted to the Einstein equations and their spherical symmetric black hole solutions. This material is quite standard and can be found in practically any book on General Relativity. A brief summary of the Kerr metric and black hole thermodynamics are given in chapter four. The main part of this chapter is devoted to spherically symmetric black holes in non-Einstein gravity (with scalar and phantom fields), black holes with regular interior, and black holes in brane worlds. Chapters five and six are mainly dedicated to wormholes and the problem of their stability. Part II (Cosmology) starts with discussion of the Friedmann-Robertson-Walker and de Sitter solutions of the Einstein equations and their properties. It follows by describing a `big picture' of the modern cosmology (inflation, post-inflationary reheating, the radiation-dominated and matter-dominated states, and modern stage of the (secondary) inflation). The authors explain how the inflation models allow one to solve many of the long-standing problems of cosmology, such as
Phantom cosmologies and fermions
International Nuclear Information System (INIS)
Chimento, Luis P; Forte, Monica; Devecchi, Fernando P; Kremer, Gilberto M
2008-01-01
Form invariance transformations can be used for constructing phantom cosmologies starting with conventional cosmological models. In this work we reconsider the scalar field case and extend the discussion to fermionic fields, where the 'phantomization' process exhibits a new class of possible accelerated regimes. As an application we analyze the cosmological constant group for a fermionic seed fluid
Particle physics and cosmology
International Nuclear Information System (INIS)
Schramm, D.N.; Turner, M.S.
1982-06-01
work is described in these areas: cosmological baryon production; cosmological production of free quarks and other exotic particle species; the quark-hadron transition in the early universe; astrophysical and cosmological constraints on particle properties; massive neutrinos; phase transitions in the early universe; and astrophysical implications of an axion-like particle
International Nuclear Information System (INIS)
Weinberg, S.
1989-01-01
Cosmological constant problem is discussed. History of the problem is briefly considered. Five different approaches to solution of the problem are described: supersymmetry, supergravity, superstring; anthropic approach; mechamism of lagrangian alignment; modification of gravitation theory and quantum cosmology. It is noted that approach, based on quantum cosmology is the most promising one
. ______________________________________________________________________________________ Nobelist George Smoot to Direct Korean Cosmology Institute Nobel Laureate George Smoot has been appointed director of a new cosmology institute in South Korea that will work closely with the year-old Berkeley the Early Universe (IEU) at EWHA Womans University in Seoul, Korea will provide cosmology education
International Nuclear Information System (INIS)
Davies, P.
1991-01-01
The main concepts of cosmology are discussed, and some of the misconceptions are clarified. The features of big bang cosmology are examined, and it is noted that the existence of the cosmic background radiation provides welcome confirmation of the big bang theory. Calculations of relative abundances of the elements conform with observations, further strengthening the confidence in the basic ideas of big bang cosmology
CERN. Geneva. Audiovisual Unit
2001-01-01
Cosmology and particle physics have enjoyed a useful relationship over the entire histories of both subjects. Today, ideas and techniques in cosmology are frequently used to elucidate and constrain theories of elementary particles. These lectures give an elementary overview of the essential elements of cosmology, which is necessary to understand this relationship.
CERN. Geneva
1999-01-01
Cosmology and particle physics have enjoyed a useful relationship over the entire histories of both subjects. Today, ideas and techniques in cosmology are frequently used to elucidate and constrain theories of elementary particles. These lectures give an elementary overview of the essential elements of cosmology, which is necessary to understand this relationship.
International Nuclear Information System (INIS)
Langer, M.
2007-01-01
This is a very concise introductory lecture to Cosmology. We start by reviewing the basics of homogeneous and isotropic cosmology. We then spend some time on the description of the Cosmic Microwave Background. Finally, a small section is devoted to the discussion of the cosmological constant and of some of the related problems
S-1 project. Volume II. Hardware. 1979 annual report
Energy Technology Data Exchange (ETDEWEB)
1979-01-01
This volume includes highlights of the design of the Mark IIA uniprocessor (SMI-2), and the SCALD II user's manual. SCALD (structured computer-aided logic design system) cuts the cost and time required to design logic by letting the logic designer express ideas as naturally as possible, and by eliminating as many errors as possible - through consistency checking, simulation, and timing verification - before the hardware is built. (GHT)
Accelerator Physics Challenges for the NSLS-II Project
Energy Technology Data Exchange (ETDEWEB)
Krinsky,S.
2009-05-04
The NSLS-II is an ultra-bright synchrotron light source based upon a 3-GeV storage ring with a 30-cell (15 super-period) double-bend-achromat lattice with damping wigglers used to lower the emittance below 1 nm. In this paper, we discuss the accelerator physics challenges for the design including: optimization of dynamic aperture; estimation of Touschek lifetime; achievement of required orbit stability; and analysis of ring impedance and collective effects.
The EMIL project at BESSY II: Beamline design and performance
Energy Technology Data Exchange (ETDEWEB)
Hendel, Stefan, E-mail: stefan.hendel@helmholtz-berlin.de; Schäfers, Franz; Reichardt, Gerd; Scheer, Michael; Bahrdt, Johannes; Lips, Klaus [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin (Germany); Hävecker, Michael [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin (Germany); MPI for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr (Germany)
2016-07-27
The Energy Materials In-Situ Laboratory Berlin (EMIL) at BESSY-II is currently under construction. Two canted undulators for soft- and hard X-rays will be installed into the BESSY II storage ring in one straight section, complex beamlines with more than twenty optical elements will be set up and a new laboratory building attached to BESSY II will host three endstations and a large UHV-transfer system connecting various HV- and UHV-deposition systems. The undulators, UE48 and U17, provide a broad energy spectrum of 80 - 10000 eV, of which the harder radiation (>700 eV) is provided by a cryogenic in-vacuum device. Three monochromators (two plane grating monochromators (PGM) and one LN{sub 2}-cooled double crystal monochromator (DCM)) disperse the radiation into separate pathways of 65 m length, while downstream of the monochromators split-mirror chambers distribute the photon beam to one (or simultaneously to two) of five upcoming endstations. Three of these endstations are designed for the full energy range with spatial overlap of the soft and hard foci, whereas one endstation (PEEM) uses only the soft and another one (PINK) only the hard branch, respectively.
[To live well: health care or life project? Part II].
Viniegra Velázquez, Leonardo
On the basis that life project as the driving force behind the life experience, the quest for human dignity is the way for true progress and the improvement of human condition. It's pointed out the need to be aware of the meaning of life understanding the motives behind our will to live that is the antecedent of life project. The proposed life project is a cognitive adventure, capable of transcending consumerism, individualism and passivity, toward the creation of a more inclusive world where the improvement spiritual, intellectual and moral can be viable. Said life project entails: a) A primary need: to link oneself with like-minded people that synergize against the prevailing order b) A core: The everlasting struggle for sublimated dignity c) A desideratum: The well-being of the majority d) An unavoidable purpose: The creation of a suitable world build on different ethical, political, lawful, cognitive and ecological foundations. In conclusion, this paper analyzes the influence of projects with an alternate proposal to the endeavors centered in healthcare that favor individualism, passivity and the current status quo. The best example of said alternate proposals is the commonly called "good death". Copyright © 2016 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.
Philosophical Roots of Cosmology
Ivanovic, M.
2008-10-01
We shall consider the philosophical roots of cosmology in the earlier Greek philosophy. Our goal is to answer the question: Are earlier Greek theories of pure philosophical-mythological character, as often philosophers cited it, or they have scientific character. On the bases of methodological criteria, we shall contend that the latter is the case. In order to answer the question about contemporary situation of the relation philosophy-cosmology, we shall consider the next question: Is contemporary cosmology completely independent of philosophical conjectures? The answer demands consideration of methodological character about scientific status of contemporary cosmology. We also consider some aspects of the relation contemporary philosophy-cosmology.
Martinet, Nicolas; Schneider, Peter; Hildebrandt, Hendrik; Shan, HuanYuan; Asgari, Marika; Dietrich, Jörg P.; Harnois-Déraps, Joachim; Erben, Thomas; Grado, Aniello; Heymans, Catherine; Hoekstra, Henk; Klaes, Dominik; Kuijken, Konrad; Merten, Julian; Nakajima, Reiko
2018-02-01
We study the statistics of peaks in a weak-lensing reconstructed mass map of the first 450 deg2 of the Kilo Degree Survey (KiDS-450). The map is computed with aperture masses directly applied to the shear field with an NFW-like compensated filter. We compare the peak statistics in the observations with that of simulations for various cosmologies to constrain the cosmological parameter S_8 = σ _8 √{Ω _m/0.3}, which probes the (Ωm, σ8) plane perpendicularly to its main degeneracy. We estimate S8 = 0.750 ± 0.059, using peaks in the signal-to-noise range 0 ≤ S/N ≤ 4, and accounting for various systematics, such as multiplicative shear bias, mean redshift bias, baryon feedback, intrinsic alignment, and shear-position coupling. These constraints are ˜ 25 per cent tighter than the constraints from the high significance peaks alone (3 ≤ S/N ≤ 4) which typically trace single-massive haloes. This demonstrates the gain of information from low-S/N peaks. However, we find that including S/N KiDS-450. Combining shear peaks with non-tomographic measurements of the shear two-point correlation functions yields a ˜20 per cent improvement in the uncertainty on S8 compared to the shear two-point correlation functions alone, highlighting the great potential of peaks as a cosmological probe.
SmartPark Technology Demonstration Project, Phase II: Final Report
2018-05-01
The purpose of FMCSA's SmartPark project was to determine the feasibility of a technology for providing truck parking space availability information in real time to truckers on the road. SmartPark consisted of two phases. Phase I was a field operatio...
Final Technical Report - Kotzebue Wind Power Project - Volume II
Energy Technology Data Exchange (ETDEWEB)
Rana Zucchi, Global Energy Concepts, LLC; Brad Reeve, Kotzebue Electric Association; DOE Project Officer - Doug Hooker
2007-10-31
The Kotzebue Wind Power Project is a joint undertaking of the U.S. Department of Energy (DOE); Kotzebue Electric Association (KEA); and the Alaska Energy Authority (AEA). The goal of the project is to develop, construct, and operate a wind power plant interconnected to a small isolated utility grid in an arctic climate in Northwest Alaska. The primary objective of KEA’s wind energy program is to bring more affordable electricity and jobs to remote Alaskan communities. DOE funding has allowed KEA to develop a multi-faceted approach to meet these objectives that includes wind project planning and development, technology transfer, and community outreach. The first wind turbines were installed in the summer of 1997 and the newest turbines were installed in the spring of 2007. The total installed capacity of the KEA wind power project is 1.16 MW with a total of 17 turbines rated between 65 kW and 100 kW. The operation of the wind power plant has resulted in a wind penetration on the utility system in excess of 35% during periods of low loads. This document and referenced attachments are presented as the final technical report for the U.S. Department of Energy (DOE) grant agreement DE-FG36-97GO10199. Interim deliverables previously submitted are also referenced within this document and where reasonable to do so, specific sections are incorporated in the report or attached as appendices.
SEL/Project Language. Level II, Kindergarten, Teacher's Handbook.
Valladares, Ann E.; Lynch, Helen C.
The Teacher's Handbook is part of the publication series of the Southeastern Education Laboratory/Project Language (SEL/PL), an 8-year language-centered program designed to alleviate the language deficiencies of disadvantaged children between the ages of four and eleven. For teachers utilizing SEL/PL, the Handbook provides a research summary and…
Projective limits of state spaces II. Quantum formalism
Lanéry, Suzanne; Thiemann, Thomas
2017-06-01
In this series of papers, we investigate the projective framework initiated by Kijowski (1977) and Okołów (2009, 2014, 2013), which describes the states of a quantum theory as projective families of density matrices. A short reading guide to the series can be found in Lanéry (2016). After discussing the formalism at the classical level in a first paper (Lanéry, 2017), the present second paper is devoted to the quantum theory. In particular, we inspect in detail how such quantum projective state spaces relate to inductive limit Hilbert spaces and to infinite tensor product constructions (Lanéry, 2016, subsection 3.1) [1]. Regarding the quantization of classical projective structures into quantum ones, we extend the results by Okołów (2013), that were set up in the context of linear configuration spaces, to configuration spaces given by simply-connected Lie groups, and to holomorphic quantization of complex phase spaces (Lanéry, 2016, subsection 2.2) [1].
Savanna ecosystem project: phase I summary and phase II progress
CSIR Research Space (South Africa)
Huntely, BJ
1978-07-01
Full Text Available A summary of the results of the first phase (mid 1974 to mid 1976) of the South African Savanna Ecosystem Project being undertaken at Nylsvley in the northern Transvaal is presented. Phase I of this ten year study of the structure and functioning...
EBR-II spent fuel treatment demonstration project
International Nuclear Information System (INIS)
Benedict, R.W.; Henslee, S.P.
1997-01-01
For approximately 10 years, Argonne National Laboratory was developed a fast reactor fuel cycle based on dry processing. When the US fast reactor program was canceled in 1994, the fuel processing technology, called the electrometallurgical technique, was adapted for treating unstable spent nuclear fuel for disposal. While this technique, which involves electrorefining fuel in a molten salt bath, is being developed for several different fuel categories, its initial application is for sodium-bonded metallic spent fuel. In June 1996, the Department of Energy (DOE) approved a radiation demonstration program in which 100 spent driver assemblies and 25 spent blanket assemblies from the Experimental Breeder Reactor-II (EBR-II) will be treated over a three-year period. This demonstrated will provide data that address issues in the National Research Council's evaluation of the technology. The planned operations will neutralize the reactive component (elemental sodium) in the fuel and produce a low enriched uranium product, a ceramic waste and a metal waste. The fission products and transuranium elements, which accumulate in the electrorefining salt, will be stabilized in the glass-bonded ceramic waste form. The stainless steel cladding hulls, noble metal fission products, and insoluble residues from the process will be stabilized in a stainless steel/zirconium alloy. Upon completion of a successful demonstration and additional environmental evaluation, the current plans are to process the remainder of the DOE sodium bonded fuel
Quantitative imaging studies with PET VI. Project II
International Nuclear Information System (INIS)
Copper, M.; Chen, C.T.; Yasillo, N.; Gatley, J.; Ortega, C.; DeJesus, O.; Friedman, A.
1985-01-01
This project is focused upon the development of hardware and software to improve PET image analysis and upon clinical applications of PET. In this report the laboratory's progress in various attenuation correction methods for brain imaging are described. The use of time-of-flight information for image reconstruction is evaluated. The location of dopamine D1 and D2 receptors in brain was found to be largely in the basal ganghia. 1 tab. (DT)
Draft Environmental Impact Statement: Proposed Tenaska, Washington II Generation Project
International Nuclear Information System (INIS)
1993-08-01
BPA is considering whether to purchase electrical power from a proposed privately-owned combustion-turbine electrical generation plant in Washington. The plant would be fired by natural gas and would use combined-cycle technology to generate 240 average megawatts (aMW) of energy. The plant would be developed, owned, and operated by Tenaska Power Partners, Inc. The project would be located about 19 kilometers (12 miles) southeast of downtown Tacoma in the Frederickson Industrial Area, Pierce County. The proposed plant would occupy about half of a 6.4-hectare (16-acre) parcel and would be consistent with the industrial character of its surroundings. The proposed site is currently undeveloped and zoned for industrial use by the county. Main environmental concerns identified in the scoping process and evaluated in the Environmental Impact Statement (EIS) include: potential air quality impacts such as emissions and their contribution to the ''greenhouse'' effect; potential health and safety impacts, such as nuisance odors, plant safety, visibility and heat-emission systems which may affect low-flying planes and potential health effects of electric and magnetic fields, and potential water quality impacts such as the amount of wastewater to be discharged, the source and amount of water required for plant operation. These and other issues are discussed in detail in the EIS. The proposed project already includes many features designed to reduce environmental impacts. Based on investigations performed for the EIS, no significant unavoidable adverse environmental impacts associated with the proposed project were identified, and no evidence emerged to suggest that the proposed action is particularly controversial. The EIS is being mailed to numerous agencies, groups, and individuals. There will be a 45-day comment period, during which a Public Hearing will be held
Project NOAH: Regulating modern sea-level rise. Phase II: Jerusalem Underground
Newman, Walter S.; Fairbridge, Rhodes W.
This proposal builds a high-speed inter-urban express between Jerusalem and Tel Aviv, generates 1500 megawatts of hydroelectric energy, curtails littoral erosion, builds a port along the Israeli Mediterranean coast and demands peaceful cooperation on both sides of the Jordan River. Phase II represents a pilot project demonstrating the feasibility of continuing to regulate world sea-level by a new series of water regulation schemes. Phase I previously described all those projects already completed or underway which have inadvertently and/or unintentionally served the purpose of sea-level regulation. These forms of Phase I sea-level regulation include large and small reservoirs, irrigation projects, water infiltration schemes, farm ponds, and swimming and reflecting pools. All these water storage projects have already exercised a very appreciable brake on 20th century sea-level rise. Phase II outlines a high-visibility proposal which will serve to illustrate the viability of “Project NOAH”.
Extending cosmology: the metric approach
Mendoza, S.
2012-01-01
Comment: 2012, Extending Cosmology: The Metric Approach, Open Questions in Cosmology; Review article for an Intech "Open questions in cosmology" book chapter (19 pages, 3 figures). Available from: http://www.intechopen.com/books/open-questions-in-cosmology/extending-cosmology-the-metric-approach
Classification of cosmology with arbitrary matter in the Horava-Lifshitz model
International Nuclear Information System (INIS)
Minamitsuji, Masato
2010-01-01
In this work, we discuss the cosmological evolutions in the nonrelativistic and possibly renormalizable gravitational theory, called the Horava-Lifshitz (HL) theory. We consider the original HL model (type I), and the modified version obtained by an analytic continuation of parameters (type II). We classify the possible cosmological evolutions with arbitrary matter. We will find a variety of cosmology.
Cosmological acceleration. Dark energy or modified gravity?
International Nuclear Information System (INIS)
Bludman, S.
2006-05-01
We review the evidence for recently accelerating cosmological expansion or ''dark energy'', either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity), without any constituent Dark Energy. If constituent Dark Energy does not exist, so that our universe is now dominated by pressure-free matter, Einstein gravity must be modified at low curvature. The vacuum symmetry of any Robertson-Walker universe then characterizes Dark Gravity as low- or high-curvature modifications of Einstein gravity. The dynamics of either kind of ''dark energy'' cannot be derived from the homogeneous expansion history alone, but requires also observing the growth of inhomogeneities. Present and projected observations are all consistent with a small fine tuned cosmological constant, but also allow nearly static Dark Energy or gravity modified at cosmological scales. The growth of cosmological fluctuations will potentially distinguish between static and ''dynamic'' ''dark energy''. But, cosmologically distinguishing the Concordance Model ΛCDM from modified gravity will require a weak lensing shear survey more ambitious than any now projected. Dvali-Gabadadze-Porrati low-curvature modifications of Einstein gravity may also be detected in refined observations in the solar system (Lue and Starkman) or at the intermediate Vainstein scale (Iorio) in isolated galaxy clusters. Dark Energy's epicyclic character, failure to explain the original Cosmic Coincidence (''Why so small now?'') without fine tuning, inaccessibility to laboratory or solar system tests, along with braneworld theories, now motivate future precision solar system, Vainstein-scale and cosmological-scale studies of Dark Gravity. (Orig.)
Cosmological acceleration. Dark energy or modified gravity?
Energy Technology Data Exchange (ETDEWEB)
Bludman, S
2006-05-15
We review the evidence for recently accelerating cosmological expansion or ''dark energy'', either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity), without any constituent Dark Energy. If constituent Dark Energy does not exist, so that our universe is now dominated by pressure-free matter, Einstein gravity must be modified at low curvature. The vacuum symmetry of any Robertson-Walker universe then characterizes Dark Gravity as low- or high-curvature modifications of Einstein gravity. The dynamics of either kind of ''dark energy'' cannot be derived from the homogeneous expansion history alone, but requires also observing the growth of inhomogeneities. Present and projected observations are all consistent with a small fine tuned cosmological constant, but also allow nearly static Dark Energy or gravity modified at cosmological scales. The growth of cosmological fluctuations will potentially distinguish between static and ''dynamic'' ''dark energy''. But, cosmologically distinguishing the Concordance Model {lambda}CDM from modified gravity will require a weak lensing shear survey more ambitious than any now projected. Dvali-Gabadadze-Porrati low-curvature modifications of Einstein gravity may also be detected in refined observations in the solar system (Lue and Starkman) or at the intermediate Vainstein scale (Iorio) in isolated galaxy clusters. Dark Energy's epicyclic character, failure to explain the original Cosmic Coincidence (''Why so small now?'') without fine tuning, inaccessibility to laboratory or solar system tests, along with braneworld theories, now motivate future precision solar system, Vainstein-scale and cosmological-scale studies of Dark Gravity. (Orig.)
Directory of Open Access Journals (Sweden)
Balbi Amedeo
2013-09-01
Full Text Available Time has always played a crucial role in cosmology. I review some of the aspects of the present cosmological model which are more directly related to time, such as: the definition of a cosmic time; the existence of typical timescales and epochs in an expanding universe; the problem of the initial singularity and the origin of time; the cosmological arrow of time.
Inflation and quantum cosmology
International Nuclear Information System (INIS)
Linde, A.
1991-01-01
In this article a review of the present status of inflationary cosmology is given. We start with a discussion of the simplest version of the chaotic inflation scenario. Then we discuss some recent develoments in the inflationary cosmology, including the theory of a self-reproducing inflationary universe (eternal chaotic inflation). We do it with the help of stochastic approach to inflation. The results obtained within this approach are compared with the results obtained in the context of Euclidean quantum cosmology. (WL)
International Nuclear Information System (INIS)
Surdin, M.
1980-01-01
It is shown that viewed from the 'outside', our universe is a black hole. Hence the 'inside' cosmology considered is termed as the Bright Universe Cosmology. The model proposed avoids the singularities of cosmologies of the Big Bang variety, it gives a good account of the redshifts, the cosmic background radiation, the number counts; it also gives a satisfactory explanation of the 'large numbers coincidence' and of the variation in time of fundamental constants. (Auth.)
Studsvik SUPER-RAMP-II: 9x9 Project
International Nuclear Information System (INIS)
Djurle, S.
1991-12-01
EPRI participated in an international program involving ramp-testing of 9 x 9 fuel rod segments in a test reactor in Sweden. The principal objective was to establish the pellet-cladding interaction (PCI) failure threshold for this type of fuel. Several segmented fuel rods were irradiated in Dresden-2 BWR with time-averaged linear heat ratings ranging from 13 to 17 kW/m up to average burnup ranging from 26 to 34 MWd/kgU. The segments were subsequently subjected to ramp-testing in the R2 reactor at Studsvik Nuclear. The ramp-testing consisted of an initial irradiation of peak linear heat rating between 12 to 16 kW/m for about two hours, followed by a rapid increase to a power level in the range of 36 to 50 kW/m. The upper power level was maintained for twelve hours or until the fuel failure was detected. The study concluded that for 9 x 9 fuel type the PCI failure threshold is ∼38 kW/m, independent of the burnup in the range of 26 to 34 MWd/kgU. This failure threshold is about 5 kW/m greater than that of traditional 8 x 8 design. Although the significance of this difference can be argued, the interim and final fuel examinations performed in this project by destructive and nondestructive methods revealed valuable detailed information on fuel performance, which is also documented and discussed in this report
Staunton 1 Reclamation Demonstration Project. Progress report II
Energy Technology Data Exchange (ETDEWEB)
None
1979-07-01
The Staunton 1 Reclamation Demonstration Project involves an evaluation of the reclamation process on a 13.8-ha abandoned deep coal mine refuse site in southwestern Illinois. The procedure included collection of preconstruction environmental data, determination of the site's final land use, and development and implementation of a detailed site development plan. Approximately 9.3 ha of refuse material was recontoured, covered with a minimum of 30 cm of soil obtained on site, and seeded with a mixture of grasses and legumes. Hydrologic investigation indicates some improvement in groundwater quality. Surface water quality also has shown improvement, but development of the aquatic ecosystem in the newly-constructed pond is slow. Revegetation has been successful, and a protective plant cover has been established on most areas of the site. Soil tests indicate that acceptable plant growth media have been constructed; however, continued application of fertilizer and limestone will probably be necessary to maintain the vegetation. The soil microbial community has achieved total numbers equal to those of old fields, but species' diversity is low. Small mammals, birds, reptiles, and amphibians have invaded and are utilizing the site. The economic value of the site and adjacent property has increased substantially, and the area's aesthetic value has been enhanced significantly. The two-year period of intensive monitoring and evaluation has been utilized to develop recommendations for improving the designs of future reclamation efforts.
International Nuclear Information System (INIS)
Feng, Jonathan L.
2005-01-01
Cosmology now provides unambiguous, quantitative evidence for new particle physics. I discuss the implications of cosmology for supersymmetry and vice versa. Topics include: motivations for supersymmetry; supersymmetry breaking; dark energy; freeze out and WIMPs; neutralino dark matter; cosmologically preferred regions of minimal supergravity; direct and indirect detection of neutralinos; the DAMA and HEAT signals; inflation and reheating; gravitino dark matter; Big Bang nucleosynthesis; and the cosmic microwave background. I conclude with speculations about the prospects for a microscopic description of the dark universe, stressing the necessity of diverse experiments on both sides of the particle physics/cosmology interface
International Nuclear Information System (INIS)
Sasaki, Misao
1983-01-01
We review the recent status of the inflationary cosmology. After exhibiting the essence of difficulties associated with the horizon, flatness and baryon number problems in the standard big-bang cosmology, we discuss that the inflationary universe scenario is one of the most plausible solutions to these fundamental cosmological problems. Since there are two qualitatively different versions of the inflationary universe scenario, we review each of them separately and discuss merits and demerits of each version. The Hawking radiation in de Sitter space is also reviewed since it may play an essential role in the inflationary cosmology. (author)
Roos, Matts
2003-01-01
The Third Edition of the hugely successful Introduction to Cosmology provides a concise, authoritative study of cosmology at an introductory level. Starting from elementary principles and the history of cosmology, the text carefully guides the student on to curved spacetimes, general relativity, black holes, cosmological models, particles and symmetries, and phase transitions. Extensively revised, this latest edition includes broader and updated coverage of distance measures, gravitational lensing and waves, dark energy and quintessence, the thermal history of the Universe, inflation,
Axions in inflationary cosmology
International Nuclear Information System (INIS)
Linde, A.
1991-01-01
The problem of the cosmological constraints on the axion mass is re-examined. It is argued that in the context of inflationary cosmology the constraint m a > or approx.10 -5 eV can be avoided even when the axion perturbations produced during inflation are taken into account. It is shown also that in most axion models the effective parameter f a rapidly changes during inflation. This modifies some earlier statements concerning isothermal perturbations in the axion cosmology. A hybrid inflation scenario is proposed which combines some advantages of chaotic inflation with specific features of new and/or extended inflation. Its implications for the axion cosmology are discussed. (orig.)
SEL/Project Language. Level II, Kindergarten, Volume II (Lessons 17-32).
Valladares, Ann E.; And Others
This curriculum guide contains the Southeastern Education Laboratory/Project Language Lessons 17-32 stressing listening, speaking, and reading readiness for disadvantaged kindergarten children. The lessons are designed to be used in the SEL's mobile preschool units or as readiness materials for kindergarten. The major emphasis of this intervention…
Advanced Technology, Inc., Reston, VA.
Stage Two of the Title IV Quality Control Project is an integrated study of quality in five related Federal financial aid programs for postsecondary students. Section 1 of the paper establishes a framework for defining quality improvements, in order to identify the types of changes that would tend to improve quality across all facets of the…
D4SCIENCE-II - Report on inter-projects coordination and collaboration
Castelli, Donatella; Zoppi, Franco
2010-01-01
This deliverable reports on the collaborations with other FP7 projects and R&D programmes established by D4Science-II from the beginning of the project until July 2010. The collaborations described are of different nature, as they range from purely technical exchanges involving mutual exploitation of technologies to the sharing of e- Infrastructure resources and to the joint organization of networking and dissemination events. The deliverable presents these collaborations clustered into: (i) ...
International Nuclear Information System (INIS)
Sievers, J.; Schulz, H.; Bass, R.; Pugh, C.; Keeney, J.
1996-11-01
A summary of Phase II of the Project for Fracture Analysis of Large-Scale International Reference Experiments (FALSIRE) is presented. A FALSIRE II Workshop focused on analyses of reference fracture experiments. More than 30 participants representing 22 organizations from 12 countries took part in the workshop. Final results for 45 analyses of the reference experiments were received from the participating analysts. For each experiment, analysis results provided estimates of variables that include temperature, crack-mouth-opening displacement, stress, strain, and applied K and J values. The data were sent electronically to the Organizing Committee, who assembled the results into a comparative data base using a special-purpose computer program. A comparative assessment and discussion of the analysis results are presented in the report. Generally, structural responses of the test specimens were predicted with tolerable scatter bands. (orig./DG)
Prioritizing sewer rehabilitation projects using AHP-PROMETHEE II ranking method.
Kessili, Abdelhak; Benmamar, Saadia
2016-01-01
The aim of this paper is to develop a methodology for the prioritization of sewer rehabilitation projects for Algiers (Algeria) sewer networks to support the National Sanitation Office in its challenge to make decisions on prioritization of sewer rehabilitation projects. The methodology applies multiple-criteria decision making. The study includes 47 projects (collectors) and 12 criteria to evaluate them. These criteria represent the different issues considered in the prioritization of the projects, which are structural, hydraulic, environmental, financial, social and technical. The analytic hierarchy process (AHP) is used to determine weights of the criteria and the Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE II) method is used to obtain the final ranking of the projects. The model was verified using the sewer data of Algiers. The results have shown that the method can be used for prioritizing sewer rehabilitation projects.
2015-01-01
As mobile technology becomes widely available and affordable, transportation agencies can use this : technology to streamline operations involved within project inspection. This research, conducted in two : phases, identified opportunities for proces...
International Nuclear Information System (INIS)
Klebanov, I.; Susskind, L.
1988-10-01
We review Coleman's wormhole mechanism for the vanishing of the cosmological constant. We find a discouraging result that wormholes much bigger than the Planck size are generated. We also consider the implications of the wormhole theory for cosmology. 7 refs., 2 figs
Particle physics and cosmology
International Nuclear Information System (INIS)
Ellis, J.; Nanopoulos, D.
1983-01-01
The authors describe the connection between cosmology and particle physics in an introductory way. In this connection the big bang theory and unified gauge models of strong, electromagnetic, and weak interactions are considered. Furthermore cosmological nucleosynthesis is discussed in this framework, and the problem of cosmic neutrinos is considered with special regards to its rest mass. (HSI).
van de Weygaert, Rien; van Albada, Tjeerd S.
1996-01-01
A detailed account of the ways in which a square kilometer array could further cosmological research. Observational and theoretical studies of the large scale structure and morphology of the local universe are reviewed against the potential capabilities of a new generation telescope. Cosmological
Barkana, Rennan; Tsujikawa, Shinji; Kim, Jihn E; Nagamine, Kentaro
2018-01-01
The Encyclopedia of Cosmology, in four volumes, is a major, long-lasting, seminal reference at the graduate student level, laid out by the most prominent, respected researchers in the general field of Cosmology. These volumes will be a comprehensive review of the most important concepts and current status in the field, covering both theory and observation.
Astroparticle physics and cosmology
International Nuclear Information System (INIS)
Senjanovic, G.; Smirnov, A.Yu.; Thompson, G.
2001-01-01
In this volume a wide spectrum of topics of modern astroparticle physics, such as neutrino astrophysics, dark matter of the universe, high energy cosmic rays, topological defects in cosmology, γ-ray bursts, phase transitions at high temperatures, is covered. The articles written by top level experts in the field give a comprehensive view of the state-of-the-art of modern cosmology
Energy Technology Data Exchange (ETDEWEB)
Vilenkin, Alexander, E-mail: vilenkin@cosmos.phy.tufts.ed [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)
2010-01-01
The 'new standard cosmology', based on the theory of inflation, has very impressive observational support. I review some outstanding problems of the new cosmology and the global view of the universe - the multiverse - that it suggests. I focus in particular on prospects for further observational tests of inflation and of the multiverse.
International Nuclear Information System (INIS)
Vilenkin, Alexander
2010-01-01
The n ew standard cosmology , based on the theory of inflation, has very impressive observational support. I review some outstanding problems of the new cosmology and the global view of the universe - the multiverse - that it suggests. I focus in particular on prospects for further observational tests of inflation and of the multiverse.
Astroparticle physics and cosmology
Energy Technology Data Exchange (ETDEWEB)
Senjanovic, G; Smirnov, A Yu; Thompson, G [eds.
2001-11-15
In this volume a wide spectrum of topics of modern astroparticle physics, such as neutrino astrophysics, dark matter of the universe, high energy cosmic rays, topological defects in cosmology, {gamma}-ray bursts, phase transitions at high temperatures, is covered. The articles written by top level experts in the field give a comprehensive view of the state-of-the-art of modern cosmology.
International Nuclear Information System (INIS)
Stecker, F.W.
1989-01-01
This paper discusses two aspects of antimatter and cosmology: 1. the fundamental cosmological question as to whether antimatter plays an equally important role as matter in the universe (overall baryon symmetry), and 2. cosmic-ray antimatter tests for the nature of the dark matter in the universe. (orig.)
Review of the water management systems in the Gujarat Medium Irrigation II Project (Credit 1496-IN)
Brouwer, R.
1993-01-01
Different activities are ongoing in the Medium Irrigation II project simultaneously. These are: - emancipation of farmers through their involvement in the operation and management; - change over from Sheshpali type water management to RWS type water management; - design and construction of remaining
76 FR 55947 - Industrial Relations Promotion Project, Phase II in Vietnam
2011-09-09
... DEPARTMENT OF LABOR Office of the Secretary Industrial Relations Promotion Project, Phase II in... to perform the type of activity to be funded.. DAI, through its Industrial Relations Promotion... provided a letter in support of continued funding of DAI/IRRP based, on part, on the importance of the...
DECOVALEX II PROJECT. Technical report - Task 1A and 1B
International Nuclear Information System (INIS)
Lanru Jing; Stephansson, Ove; Kautsky, F.
1998-08-01
DECOVALEX II project started in November 1995 as a continuation of the DECOVALEX I project, which was completed at the end of 1994. The project was initiated by recognizing the fact that a proper evaluation of the current capacities of numerical modelling of the coupled T-H-M processes in fractured media is needed not only for small scale, well controlled laboratory test cases such as those studied in DECOVALEX I, but also for less characterised, more complex and realistic in-situ experiments. This will contribute to validation and confidence building in the current mathematical models, numerical methods and computer codes. Four tasks were defined in the DECOVALEX II project: TASK 1 - numerical study of the RCF3 pumping test and shaft excavation at Sellafield by Nirex, UK; TASK 2 - numerical study of the in-situ T-H-M experiments at Kamaishi Mine by PNC, Japan; TASK 3 - review of current state-of-the-art of rock joint research and TASK 4 - report on the coupled T-H-M issues related to repository design and performance assessment. This report is one of the technical reports of the DECOVALEX II project, describing the work performed for TASK 1A and 1B - the predictions and model calibrations for the RCF 3 pumping test at Sellafield. Presented in this report are the descriptions of the project, tasks, approaches, methods and results of numerical modelling work carried out by the research teams. The report is a summary of the research reports written by the research teams and submitted to the project secretariat, and the discussions held during project workshops and task force group meetings. The opinions and conclusions in this report, however, reflect only ideas of the authors, not necessarily a collective representation of the funding organisations of the project
Lesgourgues, Julien
2012-01-01
Neutrinos can play an important role in the evolution of the Universe, modifying some of the cosmological observables. In this contribution we summarize the main aspects of cosmological relic neutrinos and we describe how the precision of present cosmological data can be used to learn about neutrino properties, in particular their mass, providing complementary information to beta decay and neutrinoless double-beta decay experiments. We show how the analysis of current cosmological observations, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure, provides an upper bound on the sum of neutrino masses of order 1 eV or less, with very good perspectives from future cosmological measurements which are expected to be sensitive to neutrino masses well into the sub-eV range.
International Nuclear Information System (INIS)
Verde, L.
2011-01-01
This is the summary of two lectures that aim to give an overview of cosmology. I will not try to be toa rigorous in derivations, nor to give a full historical overview. The idea is to provide a 'taste' of cosmology and some of the interesting topics it covers. The standard cosmological model is presented and I highlight the successes of cosmology over the past decade or so. Keys to the development of the standard cosmological model are observations of the cosmic microwave background and of large-scale structure, which are introduced. Inflation and dark energy and the outlook for the future are also discussed. Slides from the lectures are available from the school web site: physicschool.web.cern.ch/PhysicSchool/CLASHEP/CLASHEP2011/. (author)
Classical and quantum cosmology
Calcagni, Gianluca
2017-01-01
This comprehensive textbook is devoted to classical and quantum cosmology, with particular emphasis on modern approaches to quantum gravity and string theory and on their observational imprint. It covers major challenges in theoretical physics such as the big bang and the cosmological constant problem. An extensive review of standard cosmology, the cosmic microwave background, inflation and dark energy sets the scene for the phenomenological application of all the main quantum-gravity and string-theory models of cosmology. Born of the author's teaching experience and commitment to bridging the gap between cosmologists and theoreticians working beyond the established laws of particle physics and general relativity, this is a unique text where quantum-gravity approaches and string theory are treated on an equal footing. As well as introducing cosmology to undergraduate and graduate students with its pedagogical presentation and the help of 45 solved exercises, this book, which includes an ambitious bibliography...
Verde, L.
2013-06-27
This is the summary of two lectures that aim to give an overview of cosmology. I will not try to be too rigorous in derivations, nor to give a full historical overview. The idea is to provide a "taste" of cosmology and some of the interesting topics it covers. The standard cosmological model is presented and I highlight the successes of cosmology over the past decade or so. Keys to the development of the standard cosmological model are observations of the cosmic microwave background and of large-scale structure, which are introduced. Inflation and dark energy and the outlook for the future are also discussed. Slides from the lectures are available from the school website: physicschool.web.cern.ch/PhysicSchool/CLASHEP/CLASHEP2011/.
International Nuclear Information System (INIS)
Gekman, O.
1982-01-01
The brief essay of the development of the main ideas of relativistic cosmology is presented. The Einstein's cosmological work about the Universe - ''Cosmological considerations in connection with the general relativity theory'' - gave the basis to all further treatments in this field. In 1922 A. Friedman's work appeared, in which the first expanding Universe model was proposed as a solution of the Einstein field equations. The model was spherically closed, but its curvature radius was a function of time. About 1955 the searches for anisotropic homogeneous solutions to Einstein field equation began. It turned out that isotropic cosmological models are unstable in general. The predominant part of them transform to anisotropic at insignificant breaking of isotropy. The discovery of isotropic background cosmic radiation in 1965, along with the Hubble low of the Universe expansion, served as the direct confirmation of cosmology based on the Einstein theory
Workflow management for a cosmology collaboratory
International Nuclear Information System (INIS)
Loken, Stewart C.; McParland, Charles
2001-01-01
The Nearby Supernova Factory Project will provide a unique opportunity to bring together simulation and observation to address crucial problems in particle and nuclear physics. Its goal is to significantly enhance our understanding of the nuclear processes in supernovae and to improve our ability to use both Type Ia and Type II supernovae as reference light sources (standard candles) in precision measurements of cosmological parameters. Over the past several years, astronomers and astrophysicists have been conducting in-depth sky searches with the goal of identifying supernovae in their earliest evolutionary stages and, during the 4 to 8 weeks of their most ''explosive'' activity, measure their changing magnitude and spectra. The search program currently under development at LBNL is an earth-based observation program utilizing observational instruments at Haleakala and Mauna Kea, Hawaii and Mt. Palomar, California. This new program provides a demanding testbed for the integration of computational, data management and collaboratory technologies. A critical element of this effort is the use of emerging workflow management tools to permit collaborating scientists to manage data processing and storage and to integrate advanced supernova simulation into the real-time control of the experiments. This paper describes the workflow management framework for the project, discusses security and resource allocation requirements and reviews emerging tools to support this important aspect of collaborative work
The neutron utilization and promotion program of TRR-II research reactor project in Taiwan
International Nuclear Information System (INIS)
Gone, J.K.; Huang, Y.H.
2001-01-01
The objective of the Taiwan research reactor system improvement and utilization promotion project is to reconstruct the old Taiwan research reactor (TRR), which was operated by the Institute of Nuclear Energy Research (INER) between 1973 and 1988, into a multi-purpose medium flux research reactor (TRR-II). The project started in 1998, and the new reactor is scheduled to have its first critical in June of 2006. The estimated maximum unperturbed thermal neutron flux (E 14 n/cm 2 sec, and it is about one order of magnitude higher than other operating research reactors in Taiwan. The new reactor will equip with secondary neutron sources to provide neutrons with different energies, which will be an essential tool for advanced material researches in Taiwan. One of the major tasks of TRR-II project is to promote domestic utilization of neutrons generated at TRR-II. The traditional uses of neutrons in fuel/material research, trace element analysis, and isotope production has been carried out at INER for many years. On the other hand, it is obvious that promotions of neutron spectrometric technique will be a major challenge for the project team. The limited neutron flux from operating research reactors had discouraged domestic users in developing neutron spectrometric technique for many years, and only few researchers in Taiwan are experienced in using spectrometers. It is important for the project team to encourage domestic researchers to use neutron spectrometers provided by TRR-II as a tool for their future researches in various fields. This paper describes the current status of TRR-II neutron utilization and promotion program. The current status and future plans for important issues such as staff recruiting, personnel training, international collaboration, and promotion strategy will be described. (orig.)
Performance improvement with ISO 9001:2000: a case of PKOC-II project
Energy Technology Data Exchange (ETDEWEB)
Behera, U.K.; Prasad, K.S.N. [Singareni Collieries Co. Ltd. (India)
2006-07-01
The present study is limited to the study of main step towards ISO 9001:2000 (QMS) development, implementation and improvements of PKOC-II project and the same are discussed. In line with increasing global concern for quality, environmental protection and occupational health and safety, Singareni Collieries Co. Ltd (SCCL) has taken the strategic decision to implement ISO 9001:2000 (QMS), ISO 14001:2004 EMS (environmental management system) and occupational health and safety assessment series 18001:1999 (OHSAS) at the PK OC-II project. This is the first project to implement all three management systems QMS, OHSAS, and EMS, in the Indian coal industry. 25 refs., 12 figs., 2 tabs.
DECOVALEX II PROJECT. Technical report - Task 2A and 2B. (Revised edition)
International Nuclear Information System (INIS)
Lanru Jing; Stephansson, Ove
1998-08-01
DECOVALEX II project started in November 1995 as a continuation of the DECOVALEX I project, which was completed at the end of 1994. The project was initiated by recognizing the fact that a proper evaluation of the current capacities of numerical modelling of the coupled T-H-M processes in fractured media is needed not only for small scale, well controlled laboratory test cases such as those studied in DECOVALEX 1, but also for less characterised, more complex and realistic in-situ experiments. This will contribute to validation and confidence building in the current mathematical models, numerical methods and computer codes. Four tasks were defined in the DECOVALEX II project: TASK 1 - numerical study of the RCF3 pumping test and shaft excavation at Sellafield by Nirex, UK; TASK 2 - numerical study of the in-situ T-H-M experiments at Kamaishi Mine by PNC, Japan; TASK 3 - review of current state-of-the-art of rock joint research and TASK 4 - report on the coupled T-H-M issues related to repository design and performance assessment. This report is one of the technical reports of the DECOVALEX II project, describing the work performed for TASK 2A and 2B - the predictions and model calibration for the hydro-mechanical effect of the excavation of the test pit for the in-situ T-H-M experiments at Kamaishi Mine by PNC, Japan. Presented in this report are the descriptions of the project, definition of Task 2, and approaches, methods and results of numerical modelling work carried out by the research teams. The report is a summary of the research reports written by the research teams and the discussions held during project workshops and task force group meetings. The opinions and conclusions in this report, however, reflect only ideas of the authors, not necessarily a collective representation of the funding organisations of the project
Superstring thermodynamics and its application to cosmology
International Nuclear Information System (INIS)
Matsuo, N.
1987-01-01
The thermodynamics of superstring theories (SST-I, SST-II) and heterotic string theory and its application to the cosmology are studied. The free energy of superstring gas is calculated in the one-loop approximation and the stability of the extra torus dimensions is discussed. Assuming that the Einstein equation dictates the evolution of the universe, we show that matter dominated universe filled with massive particles would never be realized at the beginning of the universe, contrary to the naive expectation in the superstring cosmology. (orig.)
Phase II Final Project Report SBIR Project: "A High Efficiency PV to Hydrogen Energy System"
Energy Technology Data Exchange (ETDEWEB)
Slade, A; Turner, J; Stone, K; McConnell, R
2008-09-02
The innovative research conducted for this project contributed greatly to the understanding of generating low-cost hydrogen from solar energy. The project’s research identified two highly leveraging and complementary pathways. The first pathway is to dramatically increase the efficiency of converting sunlight into electricity. Improving solar electric conversion efficiency directly increases hydrogen production. This project produced a world record efficiency for silicon solar cells and contributed to another world record efficiency for a solar concentrator module using multijunction solar cells. The project’s literature review identified a second pathway in which wasted heat from the solar concentration process augments the electrolysis process generating hydrogen. One way to do this is to use a “heat mirror” that reflects the heat-producing infrared and transmits the visible spectrum to the solar cells; this also increases solar cell conversion efficiency. An economic analysis of this concept confirms that, if long-term concentrator photovoltaic (CPV) and solid-oxide electrolyzer cost goals can be achieved, hydrogen will be produced from solar energy cheaper than the cost of gasoline. The potential public benefits from this project are significant. The project has identified a potential energy source for the nation’s future electricity and transportation needs that is entirely “home grown” and carbon free. As CPV enter the nation’s utility markets, the opportunity for this approach to be successful is greatly increased. Amonix strongly recommends further exploration of this project’s findings.
International Nuclear Information System (INIS)
Kehagias, A.; Riotto, A.
2016-01-01
Symmetries play an interesting role in cosmology. They are useful in characterizing the cosmological perturbations generated during inflation and lead to consistency relations involving the soft limit of the statistical correlators of large-scale structure dark matter and galaxies overdensities. On the other hand, in observational cosmology the carriers of the information about these large-scale statistical distributions are light rays traveling on null geodesics. Motivated by this simple consideration, we study the structure of null infinity and the associated BMS symmetry in a cosmological setting. For decelerating Friedmann-Robertson-Walker backgrounds, for which future null infinity exists, we find that the BMS transformations which leaves the asymptotic metric invariant to leading order. Contrary to the asymptotic flat case, the BMS transformations in cosmology generate Goldstone modes corresponding to scalar, vector and tensor degrees of freedom which may exist at null infinity and perturb the asymptotic data. Therefore, BMS transformations generate physically inequivalent vacua as they populate the universe at null infinity with these physical degrees of freedom. We also discuss the gravitational memory effect when cosmological expansion is taken into account. In this case, there are extra contribution to the gravitational memory due to the tail of the retarded Green functions which are supported not only on the light-cone, but also in its interior. The gravitational memory effect can be understood also from an asymptotic point of view as a transition among cosmological BMS-related vacua.
International Nuclear Information System (INIS)
Nojiri, S; Odintsov, S D; Oikonomou, V K
2016-01-01
We combine the unimodular gravity and mimetic gravity theories into a unified theoretical framework, which is proposed to provide a suggestive proposal for a framework that may assist in the discussion and search for a solution to the cosmological constant problem and the dark matter issue. After providing the formulation of the unimodular mimetic gravity and investigating all the new features that the vacuum unimodular gravity implies, by using the underlying reconstruction method, we realize some well known cosmological evolutions, with some of these being exotic for the ordinary Einstein–Hilbert gravity. Specifically we provide the vacuum unimodular mimetic gravity description of the de Sitter cosmology and of the perfect fluid with constant equation of state cosmology. As we demonstrate, these cosmologies can be realized by vacuum mimetic unimodular gravity, without the existence of any matter fluid source. Moreover, we investigate how cosmologically viable cosmologies, which are compatible with the recent observational data, can be realized by the vacuum unimodular mimetic gravity. Since in some cases, a graceful exit from inflation problem might exist, we provide a qualitative description of the mechanism that can potentially generate the graceful exit from inflation in these theories, by searching for the unstable de Sitter solutions in the context of unimodular mimetic theories of gravity. (paper)
Energy Technology Data Exchange (ETDEWEB)
Kehagias, A. [Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece); Riotto, A. [Department of Theoretical Physics,24 quai E. Ansermet, CH-1211 Geneva 4 (Switzerland); Center for Astroparticle Physics (CAP),24 quai E. Ansermet, CH-1211 Geneva 4 (Switzerland)
2016-05-25
Symmetries play an interesting role in cosmology. They are useful in characterizing the cosmological perturbations generated during inflation and lead to consistency relations involving the soft limit of the statistical correlators of large-scale structure dark matter and galaxies overdensities. On the other hand, in observational cosmology the carriers of the information about these large-scale statistical distributions are light rays traveling on null geodesics. Motivated by this simple consideration, we study the structure of null infinity and the associated BMS symmetry in a cosmological setting. For decelerating Friedmann-Robertson-Walker backgrounds, for which future null infinity exists, we find that the BMS transformations which leaves the asymptotic metric invariant to leading order. Contrary to the asymptotic flat case, the BMS transformations in cosmology generate Goldstone modes corresponding to scalar, vector and tensor degrees of freedom which may exist at null infinity and perturb the asymptotic data. Therefore, BMS transformations generate physically inequivalent vacua as they populate the universe at null infinity with these physical degrees of freedom. We also discuss the gravitational memory effect when cosmological expansion is taken into account. In this case, there are extra contribution to the gravitational memory due to the tail of the retarded Green functions which are supported not only on the light-cone, but also in its interior. The gravitational memory effect can be understood also from an asymptotic point of view as a transition among cosmological BMS-related vacua.
Energy Technology Data Exchange (ETDEWEB)
Ronald Farris; Johanna Oxstrand; Gregory Weatherby
2011-09-01
The U.S. Department of Energy (DOE) is sponsoring research, development, and deployment on light water reactor sustainability (LWRS), in which the Idaho National Laboratory (INL) is working closely with nuclear utilities to develop technologies and solutions to help ensure the safe operational life extension of current reactors. As technologies are introduced that change the operation of the plant, the LWRS pilot projects can help identify their best-advanced uses and help demonstrate the safety of these technologies. In early testing of operator performance given these emerging technologies will ensure the safety and usability of systems prior to large-scale deployment and costly verification and validation at the plant. The aim of these collaborations, demonstrations, and approaches are intended to lessen the inertia that sustains the current status quo of today's II&C systems technology, and to motivate transformational change and a shift in strategy to a long-term approach to II&C modernization that is more sustainable. Research being conducted under Pilot Project 1 regards understanding the conditions and behaviors that can be modified, either through process improvements and/or technology deployment, to improve the overall safety and efficiency of outage control at nuclear facilities. The key component of the research in this pilot project is accessing the delivery of information that will allow researchers to simulate the control room, outage control center (OCC) information, and plant status data. The simulation also allows researchers to identify areas of opportunity where plant operating status and outage activities can be analyzed to increase overall plant efficiency. For Pilot Project 3 the desire is to demonstrate the ability of technology deployment and the subsequent impact on maximizing the 'Collective Situational Awareness' of the various stakeholders in a commercial nuclear power plant. Specifically, the desire is to show positive
International Nuclear Information System (INIS)
Farris, Ronald; Oxstrand, Johanna; Weatherby, Gregory
2011-01-01
The U.S. Department of Energy (DOE) is sponsoring research, development, and deployment on light water reactor sustainability (LWRS), in which the Idaho National Laboratory (INL) is working closely with nuclear utilities to develop technologies and solutions to help ensure the safe operational life extension of current reactors. As technologies are introduced that change the operation of the plant, the LWRS pilot projects can help identify their best-advanced uses and help demonstrate the safety of these technologies. In early testing of operator performance given these emerging technologies will ensure the safety and usability of systems prior to large-scale deployment and costly verification and validation at the plant. The aim of these collaborations, demonstrations, and approaches are intended to lessen the inertia that sustains the current status quo of today's II and C systems technology, and to motivate transformational change and a shift in strategy to a long-term approach to II and C modernization that is more sustainable. Research being conducted under Pilot Project 1 regards understanding the conditions and behaviors that can be modified, either through process improvements and/or technology deployment, to improve the overall safety and efficiency of outage control at nuclear facilities. The key component of the research in this pilot project is accessing the delivery of information that will allow researchers to simulate the control room, outage control center (OCC) information, and plant status data. The simulation also allows researchers to identify areas of opportunity where plant operating status and outage activities can be analyzed to increase overall plant efficiency. For Pilot Project 3 the desire is to demonstrate the ability of technology deployment and the subsequent impact on maximizing the 'Collective Situational Awareness' of the various stakeholders in a commercial nuclear power plant. Specifically, the desire is to show positive results
Neutrino properties from cosmology
DEFF Research Database (Denmark)
Hannestad, S.
2013-01-01
In recent years precision cosmology has become an increasingly powerful probe of particle physics. Perhaps the prime example of this is the very stringent cosmological upper bound on the neutrino mass. However, other aspects of neutrino physics, such as their decoupling history and possible non......-standard interactions, can also be probed using observations of cosmic structure. Here, I review the current status of cosmological bounds on neutrino properties and discuss the potential of future observations, for example by the recently approved EUCLID mission, to precisely measure neutrino properties....
Cosmology and particle physics
International Nuclear Information System (INIS)
Barrow, J.D.
1982-01-01
A brief overview is given of recent work that integrates cosmology and particle physics. The observational data regarding the abundance of matter and radiation in the Universe is described. The manner in which the cosmological survival density of stable massive particles can be calculated is discussed along with the process of cosmological nucleosynthesis. Several applications of these general arguments are given with reference to the survival density of nucleons, neutrinos and unconfined fractionally charge particles. The use of nucleosynthesis to limit the number of lepton generations is described together with the implications of a small neutrino mass for the origin of galaxies and clusters. (Auth.)
Cosmology and particle physics
Energy Technology Data Exchange (ETDEWEB)
Steigman, G [California Univ., Santa Barbara (USA). Inst. for Theoretical Physics; Bartol Research Foundation, Newark, Delaware (USA))
1982-01-29
The cosmic connections between physics on the very largest and very smallest scales are reviewed with an emphasis on the symbiotic relation between elementary particle physics and cosmology. After a review of the early Universe as a cosmic accelerator, various cosmological and astrophysical constraints on models of particle physics are outlined. To illustrate this approach to particle physics via cosmology, reference is made to several areas of current research: baryon non-conservation and baryon asymmetry; free quarks, heavy hadrons and other exotic relics; primordial nucleosynthesis and neutrino masses.
Neutrino properties from cosmology
CERN. Geneva
2013-01-01
Future, massive large-scale structure survey have been presented and approved.On the theory side, a significant effort has bene devoted to achieve better modeling of small scale clustering that is of cosmological non-linearities. As a result it has become clear that forthcoming cosmological data have enough statitsical power to detect the effect of non-zero neutrino mass (even at the lower mass scale limit imposed by oscillations) and to constrain the absolute neutrino mass scale.Cosmological data can also constrain the numb...
Black Holes, Cosmology and Extra Dimensions
International Nuclear Information System (INIS)
Frolov, Valeri P
2013-01-01
Book review: The book Black holes, Cosmology and Extra Dimensions written by Kirill A Bronnikov and Sergey G Rubin has been published recently by World Scientific Publishing Company. The authors are well known experts in gravity and cosmology. The book is a monograph, a considerable part of which is based on the original work of the authors. Their original point of view on some of the problems makes the book quite interesting, covering a variety of important topics of the modern theory of gravity, astrophysics and cosmology. It consists of 11 chapters which are organized in three parts. The book starts with an introduction, where the authors briefly discuss the main ideas of General Relativity, giving some historical remarks on its development and application to cosmology, and mentioning some more recent subjects such as brane worlds, f (R)−theories and gravity in higher dimensions. Part I of the book is called ‘Gravity’. Chapters two and three are devoted to the Einstein equations and their spherical symmetric black hole solutions. Part II (Cosmology) starts with discussion of the Friedmann–Robertson–Walker and de Sitter solutions of the Einstein equations and their properties. Part III covers the material on extra dimensions. It describes how Einstein gravity is modified in the presence of one or more additional spatial dimensions and how these extra dimensions are compactified in the Kaluza–Klein scheme
Energy Technology Data Exchange (ETDEWEB)
NONE
1996-01-01
This publication discusses the demonstration of the LIFAC sorbent injection technology at Richmond Power and Light`s Whitewater Valley Unit No. 2, performed under the auspices of the U.S. Department of Energy`s (DOE) Clean Coal Technology Program. LIFAC is a sorbent injection technology capable of removing 75 to 85 percent of a power plant`s SO{sub 2} emissions using limestone at calcium to sulfur molar ratios of between 2 and 2.5 to 1. The site of the demonstration is a coal-fired electric utility power plant located in Richmond, Indiana. The project is being conducted by LIFAC North America (LIFAC NA), a joint venture partnership of Tampella Power Corporation and ICF Kaiser Engineers, in cooperation with DOE, RP&L, and Research Institute (EPRI), the State of Indiana, and Black Beauty Coal Company. The purpose of Public Design Report Volume 2: Project Performance and Economics is to consolidate, for public use, the technical efficiency and economy of the LIFAC Process. The report has been prepared pursuant to the Cooperative Agreement No. DE-FC22-90PC90548 between LIFAC NA and the U.S. Department of Energy.
The cosmological constant problem
International Nuclear Information System (INIS)
Dolgov, A.D.
1989-05-01
A review of the cosmological term problem is presented. Baby universe model and the compensating field model are discussed. The importance of more accurate data on the Hubble constant and the Universe age is stressed. 18 refs
Time in contemporary cosmology
International Nuclear Information System (INIS)
Mavrides, Stamatia
1980-01-01
Cosmological time is defined, as is coordinated universal time against local times of special relativity. The problems of time and matter, age of the universe, Goedel models, arrow of time, are also discussed [fr
International Nuclear Information System (INIS)
Coule, D H
2005-01-01
We contrast the initial condition requirements of various contemporary cosmological models including inflationary and bouncing cosmologies. Canonical quantization of general relativity is used, as a first approximation to full quantum gravity, to determine whether suitable initial conditions are present. Various proposals such as Hartle-Hawking's 'no boundary' or tunnelling boundary conditions are assessed on grounds of naturalness and fine tuning. Alternatively, a quiescent initial state or an initial closed timelike curve 'time machine' is considered. Possible extensions to brane models are also addressed. Further ideas about universe creation from a meta-universe are outlined. Semiclassical and time asymmetry requirements of cosmology are briefly discussed and contrasted with the black-hole final-state proposal. We compare the recent loop quantum cosmology of Bojowald and co-workers with these earlier schemes. A number of possible difficulties and limitations are outlined. (topical review)
Cosmological Probes for Supersymmetry
Directory of Open Access Journals (Sweden)
Maxim Khlopov
2015-05-01
Full Text Available The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.
International Nuclear Information System (INIS)
Turner, Michael S.
1999-01-01
For two decades the hot big-bang model as been referred to as the standard cosmology - and for good reason. For just as long cosmologists have known that there are fundamental questions that are not answered by the standard cosmology and point to a grander theory. The best candidate for that grander theory is inflation + cold dark matter. It holds that the Universe is flat, that slowly moving elementary particles left over from the earliest moments provide the cosmic infrastructure, and that the primeval density inhomogeneities that seed all the structure arose from quantum fluctuations. There is now prima facie evidence that supports two basic tenets of this paradigm. An avalanche of high-quality cosmological observations will soon make this case stronger or will break it. Key questions remain to be answered; foremost among them are: identification and detection of the cold dark matter particles and elucidation of the dark-energy component. These are exciting times in cosmology!
International Nuclear Information System (INIS)
Senjanovic, G.; Virginia Polytechnic Inst. and State Univ., Blacksburg
1984-07-01
Extended supersymmetry, Kaluza-Klein theory and family unification all suggest the existence of mirror fermions, with same quantum numbers but opposite helicities from ordinary fermions. The laboratory and especially cosmological implications of such particles are reviewed and summarized. (author)
Lachieze-Rey, Marc
This book delivers a quantitative account of the science of cosmology, designed for a non-specialist audience. The basic principles are outlined using simple maths and physics, while still providing rigorous models of the Universe. It offers an ideal introduction to the key ideas in cosmology, without going into technical details. The approach used is based on the fundamental ideas of general relativity such as the spacetime interval, comoving coordinates, and spacetime curvature. It provides an up-to-date and thoughtful discussion of the big bang, and the crucial questions of structure and galaxy formation. Questions of method and philosophical approaches in cosmology are also briefly discussed. Advanced undergraduates in either physics or mathematics would benefit greatly from use either as a course text or as a supplementary guide to cosmology courses.
Ryden, Barbara
2017-01-01
This second edition of Introduction to Cosmology is an exciting update of an award-winning textbook. It is aimed primarily at advanced undergraduate students in physics and astronomy, but is also useful as a supplementary text at higher levels. It explains modern cosmological concepts, such as dark energy, in the context of the Big Bang theory. Its clear, lucid writing style, with a wealth of useful everyday analogies, makes it exceptionally engaging. Emphasis is placed on the links between theoretical concepts of cosmology and the observable properties of the universe, building deeper physical insights in the reader. The second edition includes recent observational results, fuller descriptions of special and general relativity, expanded discussions of dark energy, and a new chapter on baryonic matter that makes up stars and galaxies. It is an ideal textbook for the era of precision cosmology in the accelerating universe.
Tensors, relativity, and cosmology
Dalarsson, Mirjana
2015-01-01
Tensors, Relativity, and Cosmology, Second Edition, combines relativity, astrophysics, and cosmology in a single volume, providing a simplified introduction to each subject that is followed by detailed mathematical derivations. The book includes a section on general relativity that gives the case for a curved space-time, presents the mathematical background (tensor calculus, Riemannian geometry), discusses the Einstein equation and its solutions (including black holes and Penrose processes), and considers the energy-momentum tensor for various solutions. In addition, a section on relativistic astrophysics discusses stellar contraction and collapse, neutron stars and their equations of state, black holes, and accretion onto collapsed objects, with a final section on cosmology discussing cosmological models, observational tests, and scenarios for the early universe. This fully revised and updated second edition includes new material on relativistic effects, such as the behavior of clocks and measuring rods in m...
Decontamination and decommissioning project status of the TRIGA Mark II and III in Korea
International Nuclear Information System (INIS)
Paik, S.T.; Park, S.K.; Chung, K.W.; Chung, U.S.; Jung, K.J.
1999-01-01
TRIGA Mark-II, the first research reactor in Korea, has operated since 1962, and the second one, TRIGA Mark-III since 1972. Both of them had their operation phased out in 1995 due to their lives and operation of the new research reactor, HANARO (High-flux Advanced Neutron Application Reactor) at the Korea Atomic Energy Institute (KAERI) in Taejon. Decontamination and decommissioning (D and D) project of TRIGA Mark-II and Mark-III was started in January 1997 and will be completed in December 2002. The first year of the project, work was performed in preparation of the decommissioning plan, start of the environmental impact assessment and setup licensing procedure and documentation for the project with cooperation of Korea Institute of Nuclear Safety (KINS). Hyundai Engineering Company (HEC) is the main contractor to do design and licensing documentation for the D and D of both reactors. British Nuclear Fuels plc (BNFL) is the technical assisting partner of HEC. The decommissioning plan document was submitted to the Ministry of Since and Technology (MOST) for the decommissioning license in December 1998, and it expecting to be issued a license in mid 1999. The goal of this project is to release the reactor site and buildings as an unrestricted area. This paper summarizes current status and future plan for the D and D project. (author)
HIFS VNL Monthly Progress Report Preparation for NDCX-II Project
International Nuclear Information System (INIS)
Logan, Grant; Kwan, Joe; Barnard, John; Friedman, Alex; Gilson, Erik; Leitner, Matthaeus; Waldron, Will; Bieniosek, Frank
2009-01-01
In preparation for the project and for anticipated review in August, the HIFS-VNL hosted an NDCX-II Advisory Meeting at LBNL on May 27, 2009. A number of experts in accelerator physics, engineering, and construction were asked to visit for a full day, listen to presentations on the project, its goals, and its status, and to offer their advice on how best to proceed, what topics needed attention, and what technical options seemed most attractive to them. This was a productive meeting, and the Committee's comments will provide useful guidance.
Project Monitor: Part II. Conservation in small business: an exploratory study. Final report
Energy Technology Data Exchange (ETDEWEB)
Hammond, P Y
1979-08-01
Project Monitor examined the energy conservation attitude and behavior of small samples of small business owners/operators in Allegheny County, Pennsylvania, focusing on manufacturing concerns and retailers. Section I reports the findings on the energy conserving behavior of 92 smaller manufacturers and Section II identifies the factors which affect decision making concerning energy consuming activities by the owners/operators of 94 small retail establishments. In each, the impact of Project Pacesetter and of the coal strike and the general energy situation is considered. (MCW)
Implementation of MOAS II diagnosis system at the OECD Halden Reactor project
International Nuclear Information System (INIS)
Kim, I.S.; Grini, R.E.; Nilsen, S.
1995-01-01
MOAS II is a surveillance and diagnosis system that uses several techniques for knowledge acquisition and diagnostic reasoning, e.g., goal tree-success tree, simplified directed graphs, diagnosis trees, and detailed knowledge of the process, such as mass or energy balance. This new approach was used at the Halden Man-Machine Laboratory of the OECD Halden Reactor Project. The performance of MOAS II, developed in G2 real-time expert system shell for the high-pressure preheaters of the NORS process, was tested against a variety of transient scenarios, including failures of control valves and sensors, and leakage of tubes of the preheaters. These tests showed that MOAS II successfully carried out its intended functions, i.e., quickly recognizing an occurring disturbance, correctly diagnosing its cause, and presenting advice on its control to the operator. The insights gained during the implementation are discussed
Magnetohydrodynamics and Plasma Cosmology
Kleidis, Kostas; Kuiroukidis, Apostolos; Papadopoulos, Demetrios; Vlahos, Loukas
2007-09-01
We study the linear magnetohydrodynamic (MHD) equations, both in the Newtonian and the general-relativistic limit, as regards a viscous magnetized fluid of finite conductivity and discuss instability criteria. In addition, we explore the excitation of cosmological perturbations in anisotropic spacetimes, in the presence of an ambient magnetic field. Acoustic, electromagnetic (e/m) and fast-magnetosonic modes, propagating normal to the magnetic field, can be excited, resulting in several implications of cosmological significance.
International Nuclear Information System (INIS)
Novikov, I.D.
1999-01-01
In this talk a brief survey has been carried out on the development of cosmology from the days Leopold Infeld was active in the field up to the present. Attention in particular is paid to the history of our knowledge of Hubble's expansion, of the cosmological constant, of the average density of matter and its distribution, and of the related issue of possible types of matter in the Universe. (author)
Cosmological phase transitions
International Nuclear Information System (INIS)
Kolb, E.W.
1993-10-01
If modern ideas about the role of spontaneous symmetry breaking in fundamental physics are correct, then the Universe should have undergone a series of phase transitions early in its history. The study of cosmological phase transitions has become an important aspect of early-Universe cosmology. In this lecture I review some very recent work on three aspects of phase transitions: the electroweak transition, texture, and axions
Directory of Open Access Journals (Sweden)
Daywitt W. C.
2009-04-01
Full Text Available Both the big-bang and the quasi-steady-state cosmologies originate in some type of Planck state. This paper presents a new cosmological theory based on the Planck- vacuum negative-energy state, a state consisting of a degenerate collection of negative- energy Planck particles. A heuristic look at the Einstein field equation provides a con- vincing argument that such a vacuum state could provide a theoretical explanation for the visible universe.
Cosmological Models and Stability
Andersson, Lars
Principles in the form of heuristic guidelines or generally accepted dogma play an important role in the development of physical theories. In particular, philosophical considerations and principles figure prominently in the work of Albert Einstein. As mentioned in the talk by Jiří Bičák at this conference, Einstein formulated the equivalence principle, an essential step on the road to general relativity, during his time in Prague 1911-1912. In this talk, I would like to discuss some aspects of cosmological models. As cosmology is an area of physics where "principles" such as the "cosmological principle" or the "Copernican principle" play a prominent role in motivating the class of models which form part of the current standard model, I will start by comparing the role of the equivalence principle to that of the principles used in cosmology. I will then briefly describe the standard model of cosmology to give a perspective on some mathematical problems and conjectures on cosmological models, which are discussed in the later part of this paper.
Magnetized cosmological models in bimetric theory of gravitation
Indian Academy of Sciences (India)
but it should rather be chosen on the basis of cosmological consideration. Hence. Rosen proposed ... In the present work, keeping in view of the importance of Maxwell's electromag- netic field ..... project and financial support. The authors are ...
BOOK REVIEW: Observational Cosmology Observational Cosmology
Howell, Dale Andrew
2013-04-01
Observational Cosmology by Stephen Serjeant fills a niche that was underserved in the textbook market: an up-to-date, thorough cosmology textbook focused on observations, aimed at advanced undergraduates. Not everything about the book is perfect - some subjects get short shrift, in some cases jargon dominates, and there are too few exercises. Still, on the whole, the book is a welcome addition. For decades, the classic textbooks of cosmology have focused on theory. But for every Sunyaev-Zel'dovich effect there is a Butcher-Oemler effect; there are as many cosmological phenomena established by observations, and only explained later by theory, as there were predicted by theory and confirmed by observations. In fact, in the last decade, there has been an explosion of new cosmological findings driven by observations. Some are so new that you won't find them mentioned in books just a few years old. So it is not just refreshing to see a book that reflects the new realities of cosmology, it is vital, if students are to truly stay up on a field that has widened in scope considerably. Observational Cosmology is filled with full-color images, and graphs from the latest experiments. How exciting it is that we live in an era where satellites and large experiments have gathered so much data to reveal astounding details about the origin of the universe and its evolution. To have all the latest data gathered together and explained in one book will be a revelation to students. In fact, at times it was to me. I've picked up modern cosmological knowledge through a patchwork of reading papers, going to colloquia, and serving on grant and telescope allocation panels. To go back and see them explained from square one, and summarized succinctly, filled in quite a few gaps in my own knowledge and corrected a few misconceptions I'd acquired along the way. To make room for all these graphs and observational details, a few things had to be left out. For one, there are few derivations
Observed Type II supernova colours from the Carnegie Supernova Project-I
de Jaeger, T.; Anderson, J. P.; Galbany, L.; González-Gaitán, S.; Hamuy, M.; Phillips, M. M.; Stritzinger, M. D.; Contreras, C.; Folatelli, G.; Gutiérrez, C. P.; Hsiao, E. Y.; Morrell, N.; Suntzeff, N. B.; Dessart, L.; Filippenko, A. V.
2018-06-01
We present a study of observed Type II supernova (SN II) colours using optical/near-infrared photometric data from the Carnegie Supernovae Project-I. We analyse four colours (B - V, u - g, g - r, and g - Y) and find that SN II colour curves can be described by two linear regimes during the photospheric phase. The first (s1, colour) is steeper and has a median duration of ˜40 d. The second, shallower slope (s2, colour) lasts until the end of the `plateau' (˜80 d). The two slopes correlate in the sense that steeper initial colour curves also imply steeper colour curves at later phases. As suggested by recent studies, SNe II form a continuous population of objects from the colour point of view as well. We investigate correlations between the observed colours and a range of photometric and spectroscopic parameters including the absolute magnitude, the V-band light-curve slopes, and metal-line strengths. We find that less luminous SNe II appear redder, a trend that we argue is not driven by uncorrected host-galaxy reddening. While there is significant dispersion, we find evidence that redder SNe II (mainly at early epochs) display stronger metal-line equivalent widths. Host-galaxy reddening does not appear to be a dominant parameter, neither driving observed trends nor dominating the dispersion in observed colours. Intrinsic SN II colours are most probably dominated by photospheric temperature differences, with progenitor metallicity possibly playing a minor role. Such temperature differences could be related to differences in progenitor radius, together with the presence or absence of circumstellar material close to the progenitor stars.
Technical realisation of the VISA-II project, phase I, part IV, IZ-165-o268-1962
International Nuclear Information System (INIS)
Pavicevic, M.
1962-12-01
Project VISA-II is described in IX chapters as follows: introduction, definition of experiments and possibilities of performance; VISA-II channel, new experimental space in the RA reactor; hydraulic tests in the VISA-II channel; measurement of fast neutron and gamma flux in VISA-II channels; measurement of water flow through different VISA-2 irradiation capsules; fabrication of VISA-II capsules; corrosion and heavy water purity problems; safety problems of experiment VISA-2; experimental operation of VISA-II. This chapter VI includes documentation for each type of capsule, review about each experiment within the VISA-II project, the objective and purpose of the experiment as well as experimental device [sr
2016-03-07
Building on the success of developing a UAV based unpaved road assessment system in Phase I, the project team was awarded a Phase II project by the USDOT to focus on outreach and implementation. The project team added Valerie Lefler of Integrated Glo...
Patel, Ekta; Besla, Gurtina; Mandel, Kaisey
2017-07-01
In the era of high-precision astrometry, space observatories like the Hubble Space Telescope (HST) and Gaia are providing unprecedented 6D phase-space information of satellite galaxies. Such measurements can shed light on the structure and assembly history of the Local Group, but improved statistical methods are needed to use them efficiently. Here we illustrate such a method using analogues of the Local Group's two most massive satellite galaxies, the Large Magellanic Cloud (LMC) and Triangulum (M33), from the Illustris dark-matter-only cosmological simulation. We use a Bayesian inference scheme combining measurements of positions, velocities and specific orbital angular momenta (j) of the LMC/M33 with importance sampling of their simulated analogues to compute posterior estimates of the Milky Way (MW) and Andromeda's (M31) halo masses. We conclude that the resulting host halo mass is more susceptible to bias when using measurements of the current position and velocity of satellites, especially when satellites are at short-lived phases of their orbits (I.e. at pericentre). Instead, the j value of a satellite is well conserved over time and provides a more reliable constraint on host mass. The inferred virial mass of the MW (M31) using j of the LMC (M33) is {{M}}_{vir, MW} = 1.02^{+0.77}_{-0.55} × 10^{12} M⊙ ({{M}}_{vir, M31} = 1.37^{+1.39}_{-0.75} × 10^{12} M⊙). Choosing simulated analogues whose j values are consistent with the conventional picture of a previous (<3 Gyr ago), close encounter (<100 kpc) of M33 about M31 results in a very low virial mass for M31 (˜1012 M⊙). This supports the new scenario put forth in Patel, Besla & Sohn, wherein M33 is on its first passage about M31 or on a long-period orbit. We conclude that this Bayesian inference scheme, utilizing satellite j, is a promising method to reduce the current factor of 2 spread in the mass range of the MW and M31. This method is easily adaptable to include additional satellites as new 6D
The Influence of Host Galaxies in Type Ia Supernova Cosmology
Energy Technology Data Exchange (ETDEWEB)
Uddin, Syed A. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, Jiangshu (China); Mould, Jeremy [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne, VIC (Australia); Lidman, Chris; Zhang, Bonnie R. [Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Ruhlmann-Kleider, Vanina, E-mail: saushuvo@gmail.com [CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, Paris (France)
2017-10-10
We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia supernovae (SNe Ia) sourced from Carnegie Supernova Project, Center for Astrophysics Supernova Survey, Sloan Digital Sky Survey-II, and SuperNova Legacy Survey SN samples to examine the relationships between SNe Ia and the galaxies that host them. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance >5 σ ), and decline more rapidly in massive hosts (significance >9 σ ) and in hosts with low specific star formation rates (significance >8 σ ). We study the variation of these relationships with redshift and detect no evolution. We split SNe Ia into pairs of subsets that are based on the properties of the hosts and fit cosmological models to each subset. Including both systematic and statistical uncertainties, we do not find any significant shift in the best-fit cosmological parameters between the subsets. Among different SN Ia subsets, we find that SNe Ia in hosts with high specific star formation rates have the least intrinsic scatter ( σ {sub int} = 0.08 ± 0.01) in luminosity after standardization.
On the cosmological gravitational waves and cosmological distances
Belinski, V. A.; Vereshchagin, G. V.
2018-03-01
We show that solitonic cosmological gravitational waves propagated through the Friedmann universe and generated by the inhomogeneities of the gravitational field near the Big Bang can be responsible for increase of cosmological distances.
International Nuclear Information System (INIS)
Schramm, D.N.; Fields, B.; Thomas, D.
1992-01-01
The possible implications of the quark-hadron transition for cosmology are explored. Possible surviving signatures are discussed. In particular, the possibility of generating a dark matter candidate such as strange nuggets or planetary mass black holes is noted. Much discussion is devoted to the possible role of the transition for cosmological nucleosynthesis. It is emphasized that even an optimized first order phase transition will not significantly alter the nucleosynthesis constraints on the cosmological baryon density nor on neutrino counting. However, it is noted that Be and B observations in old stars may eventually be able to be a signature of a cosmologically significant quark-hadron transition. It is pointed out that the critical point in this regard is whether the observed B/Be ratio can be produced by spallation processes or requires cosmological input. Spallation cannot produce a B/Be ratio below 7.6. A supporting signature would be Be and B ratios to oxygen that greatly exceed galactic values. At present, all data is still consistent with a spallagenic origin
Inhomogeneous anisotropic cosmology
International Nuclear Information System (INIS)
Kleban, Matthew; Senatore, Leonardo
2016-01-01
In homogeneous and isotropic Friedmann-Robertson-Walker cosmology, the topology of the universe determines its ultimate fate. If the Weak Energy Condition is satisfied, open and flat universes must expand forever, while closed cosmologies can recollapse to a Big Crunch. A similar statement holds for homogeneous but anisotropic (Bianchi) universes. Here, we prove that arbitrarily inhomogeneous and anisotropic cosmologies with “flat” (including toroidal) and “open” (including compact hyperbolic) spatial topology that are initially expanding must continue to expand forever at least in some region at a rate bounded from below by a positive number, despite the presence of arbitrarily large density fluctuations and/or the formation of black holes. Because the set of 3-manifold topologies is countable, a single integer determines the ultimate fate of the universe, and, in a specific sense, most 3-manifolds are “flat” or “open”. Our result has important implications for inflation: if there is a positive cosmological constant (or suitable inflationary potential) and initial conditions for the inflaton, cosmologies with “flat” or “open” topology must expand forever in some region at least as fast as de Sitter space, and are therefore very likely to begin inflationary expansion eventually, regardless of the scale of the inflationary energy or the spectrum and amplitude of initial inhomogeneities and gravitational waves. Our result is also significant for numerical general relativity, which often makes use of periodic (toroidal) boundary conditions.
International Nuclear Information System (INIS)
2004-08-01
This Working Material (including the attached CD-ROM) documents progress made in the IAEA's initiative to preserve knowledge in the fast reactor domain. The brochure describes briefly the context of the initiative and gives an introduction to the contents of the CD-ROM. In 2003/2004 a first focus of activity was concentrated on the preservation of knowledge related to the KNK-II experimental fast reactor in Karlsruhe, Germany. The urgency of this project was given by the impending physical destruction of the installation, including the office buildings. Important KNK-II documentation was brought to safety and preserved just in time. The CD-ROM contains the full texts of 264 technical and scientific documents describing research, development and operating experience gained with the KNK-II installation over a period of time from 1965 to 2002, extending through initial investigations, 17 years of rich operating experience, and final shutdown and decommissioning. The index to the documents on the CD-ROM is printed at the end of this booklet in chronological order and is accessible on the CD by subject index and chronological index. The CD-ROM contains in its root directory also the document 'fr c lassification.pdf' which describes the classification system used for the present collection of documents on the fast reactor KNK-II
An Introduction to General Relativity and Cosmology
International Nuclear Information System (INIS)
Wainwright, John
2007-01-01
The present volume is an introduction to general relativity and cosmology, at a level suitable for beginning graduate students or advanced undergraduates. The book consists of two main parts, the first entitled 'Elements of differential geometry', and the second 'The theory of gravitation'. Chapters 2-7, part I, introduce the basic ideas of differential geometry in a general setting, and are based on previously unpublished notes by one of the authors. On the one hand, the treatment is modern in that it uses a 'top-down' approach, i.e. starting with general differentiable manifolds, and deferring the introduction of a metric tensor until after the notions of affine connection and curvature have been introduced. On the other hand, the treatment is classical in that it relies heavily, though not exclusively, on index notation. The general material, chapters 1-7, is then followed by four more specialized chapters dealing with matters of specific interest for general relativity. Part II deals with general relativity and cosmology. The basic assumptions of the theory and its application to spherically symmetric gravitational fields are discussed in two chapters, and there is some historical material and motivation for the basic assumptions at the beginning of the book. The final chapter contains a detailed discussion of the Kerr solution. But the main emphasis in part II is on relativistic cosmology, in particular the analysis of cosmological models more general than the familiar Friedmann-Lemaitre (FL) models. The material on cosmology begins with a discussion of relativistic hydrodynamics and thermodynamics. The kinematical quantities (rate of expansion, shear, etc, of a timelike congruence) are introduced and their evolution equations are derived. There follows a description of the fluid model of the Universe and optical observations in such a model, within the framework of a general spacetime geometry. The discussion is subsequently specialized to the Robertson
Tomaschitz, R
1994-01-01
Spinor fields are studied in infinite, topologically multiply connected Robertson-Walker cosmologies. Unitary spinor representations for the discrete covering groups of the spacelike slices are constructed. The spectral resolution of Dirac's equation is given in terms of horospherical elementary waves, on which the treatment of spin and energy is based in these cosmologies. The meaning of the energy and the particle-antiparticle concept is explained in the context of this varying cosmic background. Discrete symmetries, in particular inversions of the multiply connected spacelike slices, are studied. The violation of the unitarity of the parity operator, due to self-interference of P-reflected wave packets, is discussed. The violation of the CP and CPT invariance - already on the level of the free Dirac equation on this cosmological background - is pointed out.
DEFF Research Database (Denmark)
Skaanes, Thea
2015-01-01
Abstract: This article concerns Hadza cosmology examined through objects, rituals and the Hadza concept of epeme. A brief background to the Hadza and the eldwork that informs this study is followed by a close analysis of three key objects that are central to the argument presented. The objects...... are intimately linked to women and to aspects of the social and cosmological identity of the individual makers. one object is a materi- alisation of the woman’s name and it leads to an examination by interview of naming practices more generally. Naming a child gives it a spirit and places the child in a strong...... of ethnographic research indicating the potential and need for further examination of the power and role of objects in Hadza society. Keywords: Hadza, epeme, ritual, cosmology, power objects...
Silk, Joseph; Barrow, John D; Saunders, Simon
2017-01-01
Following a long-term international collaboration between leaders in cosmology and the philosophy of science, this volume addresses foundational questions at the limit of science across these disciplines, questions raised by observational and theoretical progress in modern cosmology. Space missions have mapped the Universe up to its early instants, opening up questions on what came before the Big Bang, the nature of space and time, and the quantum origin of the Universe. As the foundational volume of an emerging academic discipline, experts from relevant fields lay out the fundamental problems of contemporary cosmology and explore the routes toward finding possible solutions. Written for graduates and researchers in physics and philosophy, particular efforts are made to inform academics from other fields, as well as the educated public, who wish to understand our modern vision of the Universe, related philosophical questions, and the significant impacts on scientific methodology.
Zucker, M. H.
This paper is a critical analysis and reassessment of entropic functioning as it applies to the question of whether the ultimate fate of the universe will be determined in the future to be "open" (expanding forever to expire in a big chill), "closed" (collapsing to a big crunch), or "flat" (balanced forever between the two). The second law of thermodynamics declares that entropy can only increase and that this principle extends, inevitably, to the universe as a whole. This paper takes the position that this extension is an unwarranted projection based neither on experience nonfact - an extrapolation that ignores the powerful effect of a gravitational force acting within a closed system. Since it was originally presented by Clausius, the thermodynamic concept of entropy has been redefined in terms of "order" and "disorder" - order being equated with a low degree of entropy and disorder with a high degree. This revised terminology more subjective than precise, has generated considerable confusion in cosmology in several critical instances. For example - the chaotic fireball of the big bang, interpreted by Stephen Hawking as a state of disorder (high entropy), is infinitely hot and, thermally, represents zero entropy (order). Hawking, apparently focusing on the disorderly "chaotic" aspect, equated it with a high degree of entropy - overlooking the fact that the universe is a thermodynamic system and that the key factor in evaluating the big-bang phenomenon is the infinitely high temperature at the early universe, which can only be equated with zero entropy. This analysis resolves this confusion and reestablishes entropy as a cosmological function integrally linked to temperature. The paper goes on to show that, while all subsystems contained within the universe require external sources of energization to have their temperatures raised, this requirement does not apply to the universe as a whole. The universe is the only system that, by itself can raise its own
The Cosmology Gallery: Unity through diversity in a vast and awe-inspiring universe.
Goldsmith, John
2011-06-01
Scientists, artists, religious and cultural leaders have come together to create the Cosmology Gallery at the Gravity Discovery Centre (GDC) located 70 km north of Perth, Western Australia. The Cosmology Gallery exhibitions include the multicultural cosmology artworks, Celestial Visions astronomical photography exhibition and the Timeline of the Universe. The multicultural cosmology artworks are new artworks inspired by Australian Indigenous, Christian, Buddhist, Islamic, Hindu, scientific and technological perspectives of the universe. The Celestial Visions exhibition features astronomical events above famous landmarks, including Stonehenge and the Pyramids. The AUD 400,000+ project was funded by Lotterywest, Western Australia and the Cosmology Gallery was officially opened in July 2008 by the Premier of Western Australia.
Energy Technology Data Exchange (ETDEWEB)
Pavicevic, M; Nikolic, M [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)
1963-01-15
The second phase of the 'Project VISA-2 described in this chapter of Vol. VI includes the project specifications and technical drawings of the 'measuring system of VISA-2 for testing the VISA-2 channels outside and in the reactor'. In addition to the task objective, description of the measuring system, action plan, description of the work done it contains the definition of the task 'Leak testing' and instructions for the instrumentation personnel on duty. [Serbo-Croat] Druga faza zadatka {sup T}ehnicka realizacija projekta VISA-2' opisana u ovom poglavlju Albuma VI, sadrzi tehnicki opis i crteze 'Mernog sistema VISA-2 i ispitivanje kanala VISA-2 van reaktora i u reaktoru'. Pored definicije zadatka, opisa mernog sistema VISA-2, razrade zadatka, tekstualnog dela projekta i opisa izvedenih radova, ovo poglavlje obuhvata definiciju i razradu podzadatka 'Ispitivanje hermeticnosti' i dodatak sa instrukcijama za dezurne instrumentatore u vezi eksperimenta VISA-2.
Cosmology and the early universe
Di Bari, Pasquale
2018-01-01
This book discusses cosmology from both an observational and a strong theoretical perspective. The first part focuses on gravitation, notably the expansion of the universe and determination of cosmological parameters, before moving onto the main emphasis of the book, the physics of the early universe, and the connections between cosmological models and particle physics. Readers will gain a comprehensive account of cosmology and the latest observational results, without requiring prior knowledge of relativistic theories, making the text ideal for students.
Non equilibrium relativistic cosmology
International Nuclear Information System (INIS)
Novello, M.; Salim, J.M.
1982-01-01
A certain systematization through the discussion of results already known on cosmology and the presentation of new ones is given. In section 2 a brief review of the necessary mathematical background is also given. The theory of perturbation of Friedmann-like Universes is presented in section 3. The reduction of Einstein's equations for homogeneous Universes to an autonomous planar system of differential equations is done in section 4. Finally in section 5 the alternative gravitational non-minimal coupling and its consequences to cosmology are discussed. (Author) [pt
CERN. Geneva
2000-01-01
Most of the puzzles with standard big bang cosmology can be avoided if the big bang is NOT identified with the beginning of time. The short-distance cutoff and duality symmetries of superstring theory suggest a new (so-called pre-big bang) cosmology in which the birth of our Universe is the result of a long classical evolution characterized by a gravitational instability. I will motivate and describe this heretical scenario and compare its phenomenological implications with those of ortodox (post-big bang) inflation.
Exploring Cosmology with Supernovae
DEFF Research Database (Denmark)
Li, Xue
distribution of strong gravitational lensing is developed. For Type Ia supernova (SNe Ia), the rate is lower than core-collapse supernovae (CC SNe). The rate of SNe Ia declines beyond z 1:5. Based on these reasons, we investigate a potential candidate to measure cosmological distance: GRB......-SNe. They are a subclass of CC SNe. Light curves of GRB-SNe are obtained and their properties are studied. We ascertain that the properties of GRB-SNe make them another candidate for standardizable candles in measuring the cosmic distance. Cosmological parameters M and are constrained with the help of GRB-SNe. The first...
2012-01-01
This volume tells of the quest for cosmology as seen by some of the finest cosmologists in the world. It starts with "Galaxy Formation from Start to Finish" and ends with "The First Supermassive Black Holes in the Universe," exploring in between the grand themes of galaxies, the early universe, expansion of the universe, dark matter and dark energy. This up-to-date collection of review articles offers a general introduction to cosmology and is intended for all probing into the profound questions on where we came from and where we are going.
Silk, Joseph
2011-01-01
Horizons of Cosmology: Exploring Worlds Seen and Unseen is the fourth title published in the Templeton Science and Religion Series, in which scientists from a wide range of fields distill their experience and knowledge into brief tours of their respective specialties. In this volume, highly esteemed astrophysicist Joseph Silk explores the vast mysteries and speculations of the field of cosmology in a way that balances an accessible style for the general reader and enough technical detail for advanced students and professionals. Indeed, while the p
Relativistic Cosmology Revisited
Directory of Open Access Journals (Sweden)
Crothers S. J.
2007-04-01
Full Text Available In a previous paper the writer treated of particular classes of cosmological solutions for certain Einstein spaces and claimed that no such solutions exist in relation thereto. In that paper the assumption that the proper radius is zero when the line-element is singular was generally applied. This general assumption is unjustified and must be dropped. Consequently, solutions do exist in relation to the aforementioned types, and are explored herein. The concept of the Big Bang cosmology is found to be inconsistent with General Relativity
Tkachev, Igor
2017-01-01
This lecture course covers cosmology from the particle physicist perspective. Therefore, the emphasis will be on the evidence for the new physics in cosmological and astrophysical data together with minimal theoretical frameworks needed to understand and appreciate the evidence. I review the case for non-baryonic dark matter and describe popular models which incorporate it. In parallel, the story of dark energy will be developed, which includes accelerated expansion of the Universe today, the Universe origin in the Big Bang, and support for the Inflationary theory in CMBR data.
International Nuclear Information System (INIS)
Stabell, R.
1979-01-01
Einstein applied his gravitation theory to a universe model with positively curved space in 1917. In order to maintain a static universe he introduced the cosmological constant, which in the light of later nonstatic universe models, he described as his life's greatest mistake. The best known such model is the Einstein-de Sitter model, which is here discussed in some detail. The 'big bang' theory is also discussed leading to the cosmic background radiation. The early phase of the 'big bang' cosmology, the first ten seconds, and the first minutes are discussed, leading to the transparent stage. (JIW)
Difficulties with inflationary cosmology
International Nuclear Information System (INIS)
Penrose, R.
1989-01-01
According to the author, the idea of inflationary cosmology is an ingenious attempt to solve some of the major puzzles of cosmology, most notably the flatness problem, the homogeneity (horizon) problem, and the monopole problem. The homogeneity problem, in particular, is intimately connected with a largely unappreciated, but profound puzzle presented by the second law of thermodynamics. The author argues that the mechanism of inflation does not, by itself, come to terms with this and consequently, comes nowhere close to providing an understanding of the large-scale homogeneity of the universe
International Nuclear Information System (INIS)
Marrakchi, A.E.L.; Tapia, V.
1992-05-01
Some cosmological implications of the recently proposed fourth-rank theory of gravitation are studied. The model exhibits the possibility of being free from the horizon and flatness problems at the price of introducing a negative pressure. The field equations we obtain are compatible with k obs =0 and Ω obs t clas approx. 10 20 t Planck approx. 10 -23 s. When interpreted at the light of General Relativity the treatment is shown to be almost equivalent to that of the standard model of cosmology combined with the inflationary scenario. Hence, an interpretation of the negative pressure hypothesis is provided. (author). 8 refs
Cosmological constants and variations
International Nuclear Information System (INIS)
Barrow, John D
2005-01-01
We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that is consistent with time-variation in the fine structure 'constant' since a redshift of 3.5. The behaviour of a simple class of varying alpha cosmologies is outlined in the light of all the observational constraints. We also discuss some of the consequences of varying 'constants' for oscillating universes and show by means of exact solutions that they appear to evolve monotonically in time even though the scale factor of the universe oscillates
Computerized transportation model for the NRC Physical Protection Project. Versions I and II
International Nuclear Information System (INIS)
Anderson, G.M.
1978-01-01
Details on two versions of a computerized model for the transportation system of the NRC Physical Protection Project are presented. The Version I model permits scheduling of all types of transport units associated with a truck fleet, including truck trailers, truck tractors, escort vehicles and crews. A fixed-fleet itinerary construction process is used in which iterations on fleet size are required until the service requirements are satisfied. The Version II model adds an aircraft mode capability and provides for a more efficient non-fixed-fleet itinerary generation process. Test results using both versions are included
Conformal symmetry and holographic cosmology
Bzowski, A.W.
2013-01-01
This thesis presents a novel approach to cosmology using gauge/gravity duality. Analysis of the implications of conformal invariance in field theories leads to quantitative cosmological predictions which are in agreement with current data. Furthermore, holographic cosmology extends the theory of
Quintessence and the cosmological constant
International Nuclear Information System (INIS)
Doran, M.; Wetterich, C.
2003-01-01
Quintessence -- the energy density of a slowly evolving scalar field -- may constitute a dynamical form of the homogeneous dark energy in the universe. We review the basic idea in the light of the cosmological constant problem. Cosmological observations or a time variation of fundamental 'constants' can distinguish quintessence from a cosmological constant
Environmental compatibility investigation of the Garzweiler II open cast mine project
International Nuclear Information System (INIS)
Oster, A.; Gaertner, D.
1994-01-01
Based on an EEC directive, the law on the investigation of ecological compatibility came into force in 1990. With the application of these European directives in national law, investigations to determine the ecological compatibility must now be carried out for projects to exploit brown coal. In this connection and in conjunction with the licensing procedure for Garzweiler II, Rheinbraun in 1992 for the first time compiled data on the investigations carried out to determine the ecological compatibility of an open cast mine. The data on these investigations include information on the necessity of the open cast mine and on alternative projects that have been examined, as well as a description of the project in question as regards its nature and extent. As far as the legally specified protected objects are concerned, i.e. people, water, air, nature (animals and plants, soil, climate and landscape) as well as cultural and other material objects, itemized data are furnished on the development and effects of the project and on countermeasures and the planned traffic and transport concept. (orig.) [de
Indian Academy of Sciences (India)
in quality, quantity, and the scope of cosmological observations. While the ob- ... In this article, I summarize both the oral and poster presentations made at the workshop. ... the angular spectrum of CMB anisotropy with recent measurements of the power spectrum of ..... A thermodynamical treatment within the framework of.
Primack, Joel R.
2000-01-01
The cosmological parameters that I emphasize are the age of the universe $t_0$, the Hubble parameter $H_0 \\equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the average matter density $\\Omega_m$, the baryonic matter density $\\Omega_b$, the neutrino density $\\Omega_\
Culture and Children's Cosmology
Siegal, Michael; Butterworth, George; Newcombe, Peter A.
2004-01-01
In this investigation, we examined children's knowledge of cosmology in relation to the shape of the earth and the day-night cycle. Using explicit questioning involving a choice of alternative answers and 3D models, we carried out a comparison of children aged 4-9 years living in Australia and England. Though Australia and England have a close…
Cosmological dynamical systems
Leon, Genly
2011-01-01
In this book are studied, from the perspective of the dynamical systems, several Universe models. In chapter 1 we give a bird's eye view on cosmology and cosmological problems. Chapter 2 is devoted to a brief review on some results and useful tools from the qualitative theory of dynamical systems. They provide the theoretical basis for the qualitative study of concrete cosmological models. Chapters 1 and 2 are a review of well-known results. Chapters 3, 4, 5 and 6 are devoted to our main results. In these chapters are extended and settled in a substantially different, more strict mathematical language, several results obtained by one of us in arXiv:0812.1013 [gr-qc]; arXiv:1009.0689 [gr-qc]; arXiv:0904.1577[gr-qc]; and arXiv:0909.3571 [hep-th]. In chapter 6, we provide a different approach to the subject discussed in astro-ph/0503478. Additionally, we perform a Poincar\\'e compactification process allowing to construct a global phase space containing all the cosmological information in both finite and infinite...
International Nuclear Information System (INIS)
Schramm, D.N.
1995-01-01
Primordial nucleosynthesis has established itself as one of the three pillars of Big Bang cosmology. Many of the Big Bang Nucleosynthesis reactions involve unstable nuclei. Hence there is a tight relationship hetween the subject of this conference and cosmology. The prime role of unstable nuclei in cosmology is related to lithium synthesis and the lack of cosmological synthesis of Be and B. These nuclei will thus be focused upon. Nucleosynthesis involves comparing calculated abundances with observed abundances. In general, abundance determinations are dominated by systematic rather than statistical errors, and work on bounding systematics is crucial. The quark-hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Ω b are possible vis-a-vis the homogeneous model; hence the robustness of Ω b ∼0.05 is now apparent. (These calculations depend critically on unstable nuclei.) The above argues that the bulk of the baryons in the universe are not producing visible light. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Ω b ∼1 seems to be definitely excluded, so if Ω TOTAL =1, as some recent observations may hint, then non-baryonic dark matter is required. The implications of the recently reported halo microlensing events are discussed. In summary, it is argued that the physics of unstable nuclei affects the fundamental dark matter argument. ((orig.))
Energy Technology Data Exchange (ETDEWEB)
Sefusatti, Emiliano; /Fermilab /CCPP, New York; Crocce, Martin; Pueblas, Sebastian; Scoccimarro, Roman; /CCPP, New York
2006-04-01
The present spatial distribution of galaxies in the Universe is non-Gaussian, with 40% skewness in 50 h{sup -1} Mpc spheres, and remarkably little is known about the information encoded in it about cosmological parameters beyond the power spectrum. In this work they present an attempt to bridge this gap by studying the bispectrum, paying particular attention to a joint analysis with the power spectrum and their combination with CMB data. They address the covariance properties of the power spectrum and bispectrum including the effects of beat coupling that lead to interesting cross-correlations, and discuss how baryon acoustic oscillations break degeneracies. They show that the bispectrum has significant information on cosmological parameters well beyond its power in constraining galaxy bias, and when combined with the power spectrum is more complementary than combining power spectra of different samples of galaxies, since non-Gaussianity provides a somewhat different direction in parameter space. In the framework of flat cosmological models they show that most of the improvement of adding bispectrum information corresponds to parameters related to the amplitude and effective spectral index of perturbations, which can be improved by almost a factor of two. Moreover, they demonstrate that the expected statistical uncertainties in {sigma}s of a few percent are robust to relaxing the dark energy beyond a cosmological constant.
McFadden, P.; Skenderis, K.
2010-01-01
We propose a holographic description of four-dimensional single-scalar inflationary universes, and show how cosmological observables, such as the primordial power spectrum, are encoded in the correlation functions of a three-dimensional quantum field theory (QFT). The holographic description
International Nuclear Information System (INIS)
Novello, M.; Salim, J.M.; Torres, J.; Oliveira, H.P. de
1989-01-01
A set of spatially homogeneous and isotropic cosmological geometries generated by a class of non-perfect is investigated fluids. The irreversibility if this system is studied in the context of causal thermodynamics which provides a useful mechanism to conform to the non-violation of the causal principle. (author) [pt
Solitons in relativistic cosmologies
International Nuclear Information System (INIS)
Pullin, J.
1988-08-01
The application to the construction of solitonic cosmologies in General Relativity of the Inverse Scattering Technique of Belinskii an Zakharov is analyzed. Three improvements to the mentioned technique are proposed: the inclusion of higher order poles in the scattering matrix, a new renormalization technique for diagonal metrics and the extension of the technique to include backgrounds with material content by means of a Kaluza-Klein formalism. As a consequence of these improvements, three new aspects can be analyzed: a) The construction of anisotropic and inhomogeneous cosmological models which can mimic the formation of halos and voids, due to the presence of a material content. The new renormalization technique allows to construct an exact perturbation theory. b) The analysis of the dynamics of models with cosmological constant (inflationary models) and their perturbations. c) The study of interaction of gravitational solitonic waves on material backgrounds. Moreover, some additional works, connected with the existance of 'Crack of doom' type singularities in Kaluza-Klein cosmologies, stochastic perturbations in inflationary universes and inflationary phase transitions in rotating universes are described. (Author) [es
Indian Academy of Sciences (India)
This report is based on a recent work in collaboration with Bagla and Padmanabhan. [1]. In this paper, we construct cosmological models with homogeneous tachyon matter [2] to provide the dark energy component which drives acceleration of the universe (for a recent review of dark energy models, see [3]). We assume that.
International Nuclear Information System (INIS)
Heller, M.
1986-01-01
It is proposed to understand cosmology as a non-local physics. Non-local methods, when developed from locally performed observations, imply a considerable extrapolation, which in turn is possible without some unverifiable assumptions. Cosmology is, therefore, not only a science on the Universe but also about assumptions that render such a science possible. As far as theoretical aspects of cosmology are concerned, cosmology can be treated as a theory of the space of all solutions to Einstein's field equations (called the ensemble of universes). The very distinction is touched upon between solutions of differential equations, expressing laws of nature, and boundary conditions identifying particular instances of the law's operation. Both observational and theoretical studies demonstrate that our Universe occupies a distinguished position within the ensemble of universes. This fact remains in a close relationship with the existence and developing of structures in the Universe. Possible philosophies aimed at justifying or neutralizing our distinguished situation in the ensemble of universes are discussed at some length. 60 refs. (author)
Ekpyrotic and cyclic cosmology
International Nuclear Information System (INIS)
Lehners, Jean-Luc
2008-01-01
Ekpyrotic and cyclic cosmologies provide theories of the very early and of the very late universe. In these models, the big bang is described as a collision of branes - and thus the big bang is not the beginning of time. Before the big bang, there is an ekpyrotic phase with equation of state w=P/(ρ) >>1 (where P is the average pressure and ρ the average energy density) during which the universe slowly contracts. This phase resolves the standard cosmological puzzles and generates a nearly scale-invariant spectrum of cosmological perturbations containing a significant non-Gaussian component. At the same time it produces small-amplitude gravitational waves with a blue spectrum. The dark energy dominating the present-day cosmological evolution is reinterpreted as a small attractive force between our brane and a parallel one. This force eventually induces a new ekpyrotic phase and a new brane collision, leading to the idea of a cyclic universe. This review discusses the detailed properties of these models, their embedding in M-theory and their viability, with an emphasis on open issues and observational signatures
Energy Technology Data Exchange (ETDEWEB)
Turner, Michael S
1999-03-01
For two decades the hot big-bang model as been referred to as the standard cosmology - and for good reason. For just as long cosmologists have known that there are fundamental questions that are not answered by the standard cosmology and point to a grander theory. The best candidate for that grander theory is inflation + cold dark matter. It holds that the Universe is flat, that slowly moving elementary particles left over from the earliest moments provide the cosmic infrastructure, and that the primeval density inhomogeneities that seed all the structure arose from quantum fluctuations. There is now prima facie evidence that supports two basic tenets of this paradigm. An avalanche of high-quality cosmological observations will soon make this case stronger or will break it. Key questions remain to be answered; foremost among them are: identification and detection of the cold dark matter particles and elucidation of the dark-energy component. These are exciting times in cosmology{exclamation_point}.
Excessive extrapolations in cosmology
Czech Academy of Sciences Publication Activity Database
Křížek, Michal; Somer, L.
2016-01-01
Roč. 22, č. 3 (2016), s. 270-280 ISSN 0202-2893 Institutional support: RVO:67985840 Keywords : cosmology * friedmann equation Subject RIV: BA - General Mathematics Impact factor: 0.734, year: 2016 http://link.springer.com/article/10.1134%2FS0202289316030105
Modified geodetic brane cosmology
International Nuclear Information System (INIS)
Cordero, Rubén; Cruz, Miguel; Molgado, Alberto; Rojas, Efraín
2012-01-01
We explore the cosmological implications provided by the geodetic brane gravity action corrected by an extrinsic curvature brane term, describing a codimension-1 brane embedded in a 5D fixed Minkowski spacetime. In the geodetic brane gravity action, we accommodate the correction term through a linear term in the extrinsic curvature swept out by the brane. We study the resulting geodetic-type equation of motion. Within a Friedmann–Robertson–Walker metric, we obtain a generalized Friedmann equation describing the associated cosmological evolution. We observe that, when the radiation-like energy contribution from the extra dimension is vanishing, this effective model leads to a self-(non-self)-accelerated expansion of the brane-like universe in dependence on the nature of the concomitant parameter β associated with the correction, which resembles an analogous behaviour in the DGP brane cosmology. Several possibilities in the description for the cosmic evolution of this model are embodied and characterized by the involved density parameters related in turn to the cosmological constant, the geometry characterizing the model, the introduced β parameter as well as the dark-like energy and the matter content on the brane. (paper)
Kevane, C J
1961-02-24
A cosmological model based on a gravitational plasma of matter and antimatter is discussed. The antigravitational interaction of matter and antimatter leads to segregation and an expansion of the plasma universe. The expansion time scale is controlled by the aggregation time scale.
CSNI Project for Fracture Analyses of Large-Scale International Reference Experiments (FALSIRE II)
Energy Technology Data Exchange (ETDEWEB)
Bass, B.R.; Pugh, C.E.; Keeney, J. [Oak Ridge National Lab., TN (United States); Schulz, H.; Sievers, J. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Koeln (Gemany)
1996-11-01
A summary of Phase II of the Project for FALSIRE is presented. FALSIRE was created by the Fracture Assessment Group (FAG) of the OECD/NEA`s Committee on the Safety of Nuclear Installations (CNSI) Principal Working Group No. 3. FALSIRE I in 1988 assessed fracture methods through interpretive analyses of 6 large-scale fracture experiments in reactor pressure vessel (RPV) steels under pressurized- thermal-shock (PTS) loading. In FALSIRE II, experiments examined cleavage fracture in RPV steels for a wide range of materials, crack geometries, and constraint and loading conditions. The cracks were relatively shallow, in the transition temperature region. Included were cracks showing either unstable extension or two stages of extensions under transient thermal and mechanical loads. Crack initiation was also investigated in connection with clad surfaces and with biaxial load. Within FALSIRE II, comparative assessments were performed for 7 reference fracture experiments based on 45 analyses received from 22 organizations representing 12 countries. Temperature distributions in thermal shock loaded samples were approximated with high accuracy and small scatter bands. Structural response was predicted reasonably well; discrepancies could usually be traced to the assumed material models and approximated material properties. Almost all participants elected to use the finite element method.
CSNI Project for Fracture Analyses of Large-Scale International Reference Experiments (FALSIRE II)
International Nuclear Information System (INIS)
Bass, B.R.; Pugh, C.E.; Keeney, J.; Schulz, H.; Sievers, J.
1996-11-01
A summary of Phase II of the Project for FALSIRE is presented. FALSIRE was created by the Fracture Assessment Group (FAG) of the OECD/NEA's Committee on the Safety of Nuclear Installations (CNSI) Principal Working Group No. 3. FALSIRE I in 1988 assessed fracture methods through interpretive analyses of 6 large-scale fracture experiments in reactor pressure vessel (RPV) steels under pressurized- thermal-shock (PTS) loading. In FALSIRE II, experiments examined cleavage fracture in RPV steels for a wide range of materials, crack geometries, and constraint and loading conditions. The cracks were relatively shallow, in the transition temperature region. Included were cracks showing either unstable extension or two stages of extensions under transient thermal and mechanical loads. Crack initiation was also investigated in connection with clad surfaces and with biaxial load. Within FALSIRE II, comparative assessments were performed for 7 reference fracture experiments based on 45 analyses received from 22 organizations representing 12 countries. Temperature distributions in thermal shock loaded samples were approximated with high accuracy and small scatter bands. Structural response was predicted reasonably well; discrepancies could usually be traced to the assumed material models and approximated material properties. Almost all participants elected to use the finite element method
Post-inflationary brane cosmology
International Nuclear Information System (INIS)
Mazumdar, Anupam
2001-01-01
The brane cosmology has invoked new challenges to the usual Big Bang cosmology. In this paper we present a brief account on thermal history of the post-inflationary brane cosmology. We have realized that it is not obvious that the post-inflationary brane cosmology would always deviate from the standard Big Bang cosmology. However, if it deviates some stringent conditions on the brane tension are to be satisfied. In this regard we study various implications on gravitino production and its abundance. We discuss Affleck-Dine mechanism for baryogenesis and make some comments on moduli and dilaton problems in this context
Open problems in string cosmology
International Nuclear Information System (INIS)
Toumbas, N.
2010-01-01
Some of the open problems in string cosmology are highlighted within the context of the recently constructed thermal and quantum superstring cosmological solutions. Emphasis is given on the high temperature cosmological regime, where it is argued that thermal string vacua in the presence of gravito-magnetic fluxes can be used to bypass the Hagedorn instabilities of string gas cosmology. This article is based on a talk given at the workshop on ''Cosmology and Strings'', Corfu, September 6-13, 2009. (Abstract Copyright [2010], Wiley Periodicals, Inc.)
DEFF Research Database (Denmark)
Robertson, Amy N.; Wendt, Fabian; Jonkman, Jason M.
2017-01-01
This paper summarizes the findings from Phase II of the Offshore Code Comparison, Collaboration, Continued, with Correlation project. The project is run under the International Energy Agency Wind Research Task 30, and is focused on validating the tools used for modeling offshore wind systems thro...
The Cosmological Dependence of Galaxy Cluster Morphologies
Crone, Mary Margaret
1995-01-01
Measuring the density of the universe has been a fundamental problem in cosmology ever since the "Big Bang" model was developed over sixty years ago. In this simple and successful model, the age and eventual fate of the universe are determined by its density, its rate of expansion, and the value of a universal "cosmological constant". Analytic models suggest that many properties of galaxy clusters are sensitive to cosmological parameters. In this thesis, I use N-body simulations to examine cluster density profiles, abundances, and degree of subclustering to test the feasibility of using them as cosmological tests. The dependence on both cosmology and initial density field is examined, using a grid of cosmologies and scale-free initial power spectra P(k)~ k n. Einstein-deSitter ( Omegao=1), open ( Omegao=0.2 and 0.1) and flat, low density (Omegao=0.2, lambdao=0.8) models are studied, with initial spectral indices n=-2, -1 and 0. Of particular interest are the results for cluster profiles and substructure. The average density profiles are well fit by a power law p(r)~ r ^{-alpha} for radii where the local density contrast is between 100 and 3000. There is a clear trend toward steeper slopes with both increasing n and decreasing Omegao, with profile slopes in the open models consistently higher than Omega=1 values for the range of n examined. The amount of substructure in each model is quantified and explained in terms of cluster merger histories and the behavior of substructure statistics. The statistic which best distinguishes models is a very simple measure of deviations from symmetry in the projected mass distribution --the "Center-of-Mass Shift" as a function of overdensity. Some statistics which are quite sensitive to substructure perform relatively poorly as cosmological indicators. Density profiles and the Center-of-Mass test are both well-suited for comparison with weak lensing data and galaxy distributions. Such data are currently being collected and should
National Oceanic and Atmospheric Administration, Department of Commerce — The NCEP-DOE Atmospheric Model Intercomparison Project (AMIP-II) reanalysis is a follow-on project to the "50-year" (1948-present) NCEP-NCAR Reanalysis Project....
Quantum cosmology - science of Genesis
International Nuclear Information System (INIS)
Padmanabhan, Thanu
1987-01-01
Quantum cosmology, the marriage between the theories of the microscopic and macroscopic Universe, is examined in an attempt to explain the birth of the Universe in the 'big bang'. A quantum cosmological model of the Universe does not exist, but a rough approximation, or 'poor man's' version of quantum cosmology has been developed. The idea is to combine the theory of quantum mechanics with the classical cosmological solutions to obtain a quantum mechanical version of cosmology. Such a model of quantum cosmology is described -here the quantum universe behaves like a hydrogen atom with the Planck length replacing the Bohr radius. Properties of quantum cosmologies and the significance of the Planck length are both discussed. (UK)
Anisotropic cosmological constant and the CMB quadrupole anomaly
International Nuclear Information System (INIS)
Rodrigues, Davi C.
2008-01-01
There are evidences that the cosmic microwave background (CMB) large-angle anomalies imply a departure from statistical isotropy and hence from the standard cosmological model. We propose a ΛCDM model extension whose dark energy component preserves its nondynamical character but wields anisotropic vacuum pressure. Exact solutions for the cosmological scale factors are presented, upper bounds for the deformation parameter are evaluated and its value is estimated considering the elliptical universe proposal to solve the quadrupole anomaly. This model can be constructed from a Bianchi I cosmology with a cosmological constant from two different ways: (i) a straightforward anisotropic modification of the vacuum pressure consistently with energy-momentum conservation; (ii) a Poisson structure deformation between canonical momenta such that the dynamics remain invariant under scale factors rescalings
Numerical cosmology: Revealing the universe using computers
International Nuclear Information System (INIS)
Centrella, J.; Matzner, R.A.; Tolman, B.W.
1986-01-01
In this paper the authors present two research projects which study the evolution of different periods in the history of the universe using numerical simulations. The first investigates the synthesis of light elements in an inhomogeneous early universe dominated by shocks and non-linear gravitational waves. The second follows the evolution of large scale structures during the later history of the universe and calculates their effect on the 3K background radiation. Their simulations are carried out using modern supercomputers and make heavy use of multidimensional color graphics, including film to elucidate the results. Both projects provide the authors the opportunity to do experiments in cosmology and assess their results against fundamental cosmological observations
Energy Technology Data Exchange (ETDEWEB)
Hogan, Mark [SLAC National Accelerator Lab., Menlo Park, CA (United States)
2016-04-22
Plasma wakefield acceleration has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider is the focus of FACET, a National User Facility at SLAC. The existing FACET National User Facility uses part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and positrons. FACET-II is a new test facility to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. It is the only facility in the world with high energy positron beams. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The design parameters for FACET-II are set by the requirements of the plasma wakefield experimental program. To drive the plasma wakefield requires a high peak current, in excess of 10kA. To reach this peak current, the electron and positron design bunch size is 10μ by 10μ transversely with a bunch length of 10μ. This is more than 200 times better than what has been achieved at the existing FACET. The beam energy is 10 GeV, set by the Linac length available and the repetition rate is up to 30 Hz. The FACET-II project is scheduled to be constructed in three major stages. Components of the project discussed in detail include the following: electron injector, bunch compressors and linac, the positron system, the Sector 20 sailboat and W chicanes
International Nuclear Information System (INIS)
2006-01-01
This year's Nobel prize is welcome recognition for cosmology. Back in the 1960s, according to Paul Davies' new book The Goldilocks Enigma (see 'Seeking anthropic answers' in this issue), cynics used to quip that there is 'speculation, speculation squared - and cosmology'. Anyone trying to understand the origin and fate of the universe was, in other words, dealing with questions that were simply impractical - or even impossible - to answer. But that has all changed with the development of new telescopes, satellites and data-processing techniques - to the extent that cosmology is now generally viewed as a perfectly acceptable branch of science. If anyone was in any doubt of cosmology's new status, the Royal Swedish Academy of Sciences last month gave the subject welcome recognition with the award of this year's Nobel prize to John Mather and George Smoot (see pp6-7; print version only). The pair were the driving force behind the COBE satellite that in 1992 produced the now famous image of the cosmic microwave background. The mission's data almost certainly proved that the universe started with a Big Bang, while tiny fluctuations in the temperature signal between different parts of the sky were shown to be the seeds of the stars and galaxies we see today. These results are regarded by many as the start of a new era of 'precision cosmology'. But for cosmologists, the job is far from over. There are still massive holes in our understanding of the cosmos, notably the nature of dark matter and dark energy, which together account for over 95% of the total universe. Indeed, some regard dark energy and matter as just ad hoc assumptions needed to fit the data. (Hypothetical particles called 'axions' are one possible contender for dark matter (see pp20-23; print version only), but don't bet your house on it.) Some physicists even think it makes more sense to adjust Newtonian gravity rather than invoke dark matter. But the notion that cosmology is in crisis, as argued by some
Phantom cosmology without Big Rip singularity
Energy Technology Data Exchange (ETDEWEB)
Astashenok, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation); Nojiri, Shin' ichi, E-mail: nojiri@phys.nagoya-u.ac.jp [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Odintsov, Sergei D. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Institucio Catalana de Recerca i Estudis Avancats - ICREA and Institut de Ciencies de l' Espai (IEEC-CSIC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra (Barcelona) (Spain); Tomsk State Pedagogical University, Tomsk (Russian Federation); Yurov, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation)
2012-03-23
We construct phantom energy models with the equation of state parameter w which is less than -1, w<-1, but finite-time future singularity does not occur. Such models can be divided into two classes: (i) energy density increases with time ('phantom energy' without 'Big Rip' singularity) and (ii) energy density tends to constant value with time ('cosmological constant' with asymptotically de Sitter evolution). The disintegration of bound structure is confirmed in Little Rip cosmology. Surprisingly, we find that such disintegration (on example of Sun-Earth system) may occur even in asymptotically de Sitter phantom universe consistent with observational data. We also demonstrate that non-singular phantom models admit wormhole solutions as well as possibility of Big Trip via wormholes.
Magnetic monopoles in particle physics and cosmology
International Nuclear Information System (INIS)
Preskill, J.
1986-01-01
Hardly any topic better illustrates the connection between particle physics and cosmology than the topic of magnetic monopoles. While there is no persuasive evidence that a monopole has ever been detected, the existence of monopoles is implied by deeply cherished beliefs about the structure of matter at extremely short distances. And the fact that monopoles are so rare as to have escaped detection has profound implications concerning the very early history of the universe. This article gives a brief overview of the theory of magnetic monopoles and its relevance to cosmology. In Section II, the author explains the connection between monopoles and the unification of the fundamental interactions. In Section III, he describes how monopoles might have been produced in the very early universe. Theoretical limits on the abundance of monopoles derived from astrophysical considerations are the subject of Section IV. Section V contains conclusions
Phantom cosmology without Big Rip singularity
International Nuclear Information System (INIS)
Astashenok, Artyom V.; Nojiri, Shin'ichi; Odintsov, Sergei D.; Yurov, Artyom V.
2012-01-01
We construct phantom energy models with the equation of state parameter w which is less than -1, w<-1, but finite-time future singularity does not occur. Such models can be divided into two classes: (i) energy density increases with time (“phantom energy” without “Big Rip” singularity) and (ii) energy density tends to constant value with time (“cosmological constant” with asymptotically de Sitter evolution). The disintegration of bound structure is confirmed in Little Rip cosmology. Surprisingly, we find that such disintegration (on example of Sun-Earth system) may occur even in asymptotically de Sitter phantom universe consistent with observational data. We also demonstrate that non-singular phantom models admit wormhole solutions as well as possibility of Big Trip via wormholes.
Supersymmetric null-like holographic cosmologies
International Nuclear Information System (INIS)
Lin Fengli; Wen Wenyu
2006-01-01
We construct a new class of 1/4-BPS time dependent domain-wall solutions with null-like metric and dilaton in type II supergravities, which admit a null-like big bang singularity. Based on the domain-wall/QFT correspondence, these solutions are dual to 1/4-supersymmetric quantum field theories living on a boundary cosmological background with time dependent coupling constant and UV cutoff. In particular we evaluate the holographic c function for the 2-dimensional dual field theory living on the corresponding null-like cosmology. We find that this c function runs in accordance with the c-theorem as the boundary universe evolves, this means that the number of degrees of freedom is divergent at big bang and suggests the possible resolution of big bang singularity
Measures, Probability and Holography in Cosmology
Phillips, Daniel
This dissertation compiles four research projects on predicting values for cosmological parameters and models of the universe on the broadest scale. The first examines the Causal Entropic Principle (CEP) in inhomogeneous cosmologies. The CEP aims to predict the unexpectedly small value of the cosmological constant Lambda using a weighting by entropy increase on causal diamonds. The original work assumed a purely isotropic and homogeneous cosmology. But even the level of inhomogeneity observed in our universe forces reconsideration of certain arguments about entropy production. In particular, we must consider an ensemble of causal diamonds associated with each background cosmology and we can no longer immediately discard entropy production in the far future of the universe. Depending on our choices for a probability measure and our treatment of black hole evaporation, the prediction for Lambda may be left intact or dramatically altered. The second related project extends the CEP to universes with curvature. We have found that curvature values larger than rho k = 40rhom are disfavored by more than $99.99% and a peak value at rhoLambda = 7.9 x 10-123 and rhok =4.3rho m for open universes. For universes that allow only positive curvature or both positive and negative curvature, we find a correlation between curvature and dark energy that leads to an extended region of preferred values. Our universe is found to be disfavored to an extent depending the priors on curvature. We also provide a comparison to previous anthropic constraints on open universes and discuss future directions for this work. The third project examines how cosmologists should formulate basic questions of probability. We argue using simple models that all successful practical uses of probabilities originate in quantum fluctuations in the microscopic physical world around us, often propagated to macroscopic scales. Thus we claim there is no physically verified fully classical theory of probability. We
CERN. Geneva
2017-01-01
Extensions of Einstein’s theory of General Relativity are under investigation as a potential explanation of the accelerating expansion rate of the universe. I’ll present a cosmologist’s overview of attempts to test these ideas in an efficient and unbiased manner. I’ll start by introducing the bestiary of alternative gravity theories that have been put forwards. This proliferation of models motivates us to develop model-independent, agnostic tools for comparing the theory space to cosmological data. I’ll introduce the effective field theory for cosmological perturbations, a framework designed to unify modified gravity theories in terms of a manageable set of parameters. Having outlined the formalism, I’ll talk about the current constraints on this framework, and the improvements expected from the next generation of large galaxy clustering, weak lensing and intensity mapping experiments.
Towards a superstring cosmology
International Nuclear Information System (INIS)
Taylor, J.G.
1987-01-01
If superstring theory is a theory of everything then it must give a satisfactory description of the very early evolution of the universe. Since the very early universe is not directly observable, then by satisfactory it is mean that the later evolution following the earlier (pre-Planck time era) phase leads to agreement with prediction for the various observable phenomena such as (B-bar B), inflation, galaxy structure, the cosmological constant (infimum), etc. Moreover it is to be hoped that the initial singularity of classical general relativistic cosmology is also avoided. It is clear that superstring theory is not yet able to tackle these problems. This paper describes what has been done so far to construct very simplified versions of string theory relevant to the early universe, and discusses the critical questions still to be answered
Nonlocal teleparallel cosmology.
Bahamonde, Sebastian; Capozziello, Salvatore; Faizal, Mir; Nunes, Rafael C
2017-01-01
Even though it is not possible to differentiate general relativity from teleparallel gravity using classical experiments, it could be possible to discriminate between them by quantum gravitational effects. These effects have motivated the introduction of nonlocal deformations of general relativity, and similar effects are also expected to occur in teleparallel gravity. Here, we study nonlocal deformations of teleparallel gravity along with its cosmological solutions. We observe that nonlocal teleparallel gravity (like nonlocal general relativity) is consistent with the present cosmological data obtained by SNe Ia + BAO + CC + [Formula: see text] observations. Along this track, future experiments probing nonlocal effects could be used to test whether general relativity or teleparallel gravity gives the most consistent picture of gravitational interaction.
Bojowald, Martin
2015-02-01
In quantum cosmology, one applies quantum physics to the whole universe. While no unique version and no completely well-defined theory is available yet, the framework gives rise to interesting conceptual, mathematical and physical questions. This review presents quantum cosmology in a new picture that tries to incorporate the importance of inhomogeneity. De-emphasizing the traditional minisuperspace view, the dynamics is rather formulated in terms of the interplay of many interacting 'microscopic' degrees of freedom that describe the space-time geometry. There is thus a close relationship with more-established systems in condensed-matter and particle physics even while the large set of space-time symmetries (general covariance) requires some adaptations and new developments. These extensions of standard methods are needed both at the fundamental level and at the stage of evaluating the theory by effective descriptions.
Elementary particles and cosmology
International Nuclear Information System (INIS)
Audouze, J.; Paty, M.
2000-01-01
The universe is the most efficient laboratory of particle physics and the understanding of cosmological processes implies the knowledge of how elementary particles interact. This article recalls the mutual influences between on the one hand: astrophysics and cosmology and on the other hand: nuclear physics and particle physics. The big-bang theory relies on nuclear physics to explain the successive stages of nucleo-synthesis and the study of solar neutrinos has led to discover new aspects of this particle: it is likely that neutrinos undergo oscillations from one neutrino type to another. In some universe events such as the bursting of a super-nova, particles are released with a kinetic energy that would be impossible to reach on earth with a particle accelerator. These events are become common points of interest between astrophysicists and particle physicists and have promoted a deeper cooperation between astrophysics and elementary particle physics. (A.C.)
Nonlocal teleparallel cosmology
Energy Technology Data Exchange (ETDEWEB)
Bahamonde, Sebastian [University College London, Department of Mathematics, London (United Kingdom); Capozziello, Salvatore [Universita di Napoli ' ' Federico II' ' , Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Compl. Univ. di Monte S. Angelo, Naples (Italy); INFN, Napoli (Italy); Faizal, Mir [University of British Columbia - Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Nunes, Rafael C. [Universidade Federal de Juiz de Fora, Departamento de Fisica, Juiz de Fora, MG (Brazil)
2017-09-15
Even though it is not possible to differentiate general relativity from teleparallel gravity using classical experiments, it could be possible to discriminate between them by quantum gravitational effects. These effects have motivated the introduction of nonlocal deformations of general relativity, and similar effects are also expected to occur in teleparallel gravity. Here, we study nonlocal deformations of teleparallel gravity along with its cosmological solutions. We observe that nonlocal teleparallel gravity (like nonlocal general relativity) is consistent with the present cosmological data obtained by SNe Ia + BAO + CC + H{sub 0} observations. Along this track, future experiments probing nonlocal effects could be used to test whether general relativity or teleparallel gravity gives the most consistent picture of gravitational interaction. (orig.)
Supersymmetric GUTs and cosmology
International Nuclear Information System (INIS)
Lazarides, G.; Shafi, Q.
1982-06-01
By examining the behaviour of supersymmetric GUTs in the very early universe we find two classes of realistic models. In one of them supersymmetry is broken at or near the superheavy GUT scale. The cosmological implications of such models are expected to be similar to those of nonsupersymmetric GUTs. In the second class of models, the superheavy GUT scale is related to the supersymmetry breaking scale a la Witten. Two types of cosmological scenarios appear possible in this case, either with or without an intermediate (new) inflationary phase. They can be experimentally distinguished, since the former predicts an absence and the latter an observable number density of superheavy monopoles. A mechanism for generating baryon asymmetry in such models is pointed out. Further constraint on model building appears if global R invariance is employed to resolve the strong CP problem. (author)
International Nuclear Information System (INIS)
Padmanabhan, T.
1989-01-01
Quantum cosmology is to quantum gravity what the Bohr model is to the full quantum mechanical description of the hydrogen atom. In quantum cosmology one attempts to give a quantum-mechanical meaning to classical solutions of general relativity. This is discussed in this chapter. The approach is illustrated by quantizing only the conformal degree of freedom of the gravitational field, in particular the Friedmann-Robertson-Walker models. And, as in the hydrogen atom, the classical singularity of general relativity is avoided and one has analogous stationary states in the quantum Universe. The chapter ends with a model of the fundamental role that the Planck length may play as the universal cutoff in all field theories, thus ridding the theory of ultra-violet divergences. Two appendices introduce field theory in the Schroedinger representation and the Schroedinger equation for quantum gravity, namely the Wheeler-De Wit equation. (author). 38 refs.; 2 figs.; 1 tab
Massive neutrinos and cosmology
International Nuclear Information System (INIS)
Shandarin, S.F.
1991-01-01
This paper discussed the importance of the consequences of a nonzero neutrino rest mass on cosmology, perhaps, first recognized by Gershtein and Zeldovich, after the discover of the 3-K microwave background radiation MBR. Since the first works on the primordial synthesis of 4 He, it has been known that additional neutrino species increase the rate of expansion of the universe during the epoch of the primordial nucleosynthesis, which increases the yield of 4 He. Combining the results of the theory with astronomical measurements of the 4 He abundance and the estimate of the mass density of MBR, Shvartsman suggested the upper limit on the mass density of all relativistic matter at that epoch: ρ rel ≤ 5ρ MBR which eventually became the upper limit for the number of neutrino species: N ν ≤ 7. At that time, the constraints based on cosmological arguments were much stronger than one based on laboratory experiments
Merritt, David
2017-02-01
I argue that some important elements of the current cosmological model are 'conventionalist' in the sense defined by Karl Popper. These elements include dark matter and dark energy; both are auxiliary hypotheses that were invoked in response to observations that falsified the standard model as it existed at the time. The use of conventionalist stratagems in response to unexpected observations implies that the field of cosmology is in a state of 'degenerating problemshift' in the language of Imre Lakatos. I show that the 'concordance' argument, often put forward by cosmologists in support of the current paradigm, is weaker than the convergence arguments that were made in the past in support of the atomic theory of matter or the quantization of energy.
Cosmology, inflation, and supersymmetry
International Nuclear Information System (INIS)
Albrecht, A.; Dimopoulos, S.; Fischler, W.; Kolb, E.W.; Raby, S.; Steinhardt, P.J.
1982-01-01
Cosmological consequences of supersymmetric grand unified models based on the Witten-O'Raifeartaigh potential are discussed. In particular we study the development of the phase transition in the spontaneous breaking of supersymmetry. We find that in realistic models where light fields feel supersymmetry breaking only through coupling to massive fields, e.g., the Geometric Hierarchy model, the universe does not inflate or reheat. Thus, the standard cosmological flatness, monopole, and horizon problems remain. In addition, we find that the transition is never completed, in the sense that the universe remains dominated by coherent Higgs field energy, resulting in an apparent matter dominated universe with Ω greater than or equal to 10 30
Energy Technology Data Exchange (ETDEWEB)
United States. Bonneville Power Administration.
1994-01-01
In regard to the proposed Tenaska Washington II Generation Project, the goal of the Bonneville Power Administration`s (BPA) Environmental Impact Statement (EIS) public involvement process is to determine the issues to be examined and pertinent analyses to be conducted and to solicit comments on the content and quality of information presented in the Draft Environmental Impact Statement (DEIS). Comments and questions are solicited from the public and government agencies during the scoping process and during the comment period and public hearing on the DEIS, to find out what is of most concern to them. The end product of the public involvement process is the Comment Report which follows in part of this volume on Public Involvement.
Nonlinear electrodynamics and cosmology
International Nuclear Information System (INIS)
Breton, Nora
2010-01-01
Nonlinear electrodynamics (NLED) generalizes Maxwell's theory for strong fields. When coupled to general relativity NLED presents interesting features like the non-vanishing of the trace of the energy-momentum tensor that leads to the possibility of violation of some energy conditions and of acting as a repulsive contribution in the Raychaudhuri equation. This theory is worth to study in cosmological and astrophysical situations characterized by strong electromagnetic and gravitational fields.
International Nuclear Information System (INIS)
Fré, P.; Sorin, A.S.; Trigiante, M.
2014-01-01
The question whether the integrable one-field cosmologies classified in a previous paper by Fré, Sagnotti and Sorin can be embedded as consistent one-field truncations into Extended Gauged Supergravity or in N=1 supergravity gauged by a superpotential without the use of D-terms is addressed in this paper. The answer is that such an embedding is very difficult and rare but not impossible. Indeed, we were able to find two examples of integrable models embedded in supergravity in this way. Both examples are fitted into N=1 supergravity by means of a very specific and interesting choice of the superpotential W(z). The question whether there are examples of such an embedding in Extended Gauged Supergravity remains open. In the present paper, relying on the embedding tensor formalism we classified all gaugings of the N=2 STU model, confirming, in the absence on hypermultiplets, the uniqueness of the stable de Sitter vacuum found several years ago by Fré, Trigiante and Van Proeyen and excluding the embedding of any integrable cosmological model. A detailed analysis of the space of exact solutions of the first supergravity-embedded integrable cosmological model revealed several new features worth an in-depth consideration. When the scalar potential has an extremum at a negative value, the Universe necessarily collapses into a Big Crunch notwithstanding its spatial flatness. The causal structure of these Universes is quite different from that of the closed, positive curved, Universe: indeed, in this case the particle and event horizons do not coincide and develop complicated patterns. The cosmological consequences of this unexpected mechanism deserve careful consideration
Cosmology, Clusters and Calorimeters
Figueroa-Feliciano, Enectali
2005-01-01
I will review the current state of Cosmology with Clusters and discuss the application of microcalorimeter arrays to this field. With the launch of Astro-E2 this summer and a slew of new missions being developed, microcalorimeters are the next big thing in x-ray astronomy. I will cover the basics and not-so-basic concepts of microcalorimeter designs and look at the future to see where this technology will go.
Energy Technology Data Exchange (ETDEWEB)
Klimek, Z.
1981-01-01
The evolution of Friedman models with bulk viscosity in the plane ''Hubble's constant'' - energy density is presented. The general conclusions are: viscosity leads to intense energy production - energy density increases in spite of expansion; if the above result can be regarded as non-physical, the bulk viscosity can produce cosmological models without the initial singularity only for flat universes; the results do not essentially depend on the equation of state.
Supersymmetric inflationary cosmology
International Nuclear Information System (INIS)
Ruiz-Altaba, M.
1986-06-01
An action is presented, within the framework of supergravity unification, which satisfies all experimental and cosmological constraints. In intermediate scale, around 10 10 - 10 11 GeV, arises from a critical examination of inflation, supersymmetry breaking, fermion masses, proton decay, baryogenesis, and electroweak breaking - including neutrino oscillations and CP violation. Careful consideration is given to some relevant calculations. 86 refs., 10 figs., 5 tabs
International Nuclear Information System (INIS)
Klimek, Z.
1981-01-01
The evolution of Friedman models with bulk viscosity in the plane ''Hubble's constant'' - energy density is presented. The general conclusions are: viscosity leads to intense energy production - energy density increases in spite of expansion; if the above result be regarded as non-physical, the bulk viscosity can produce cosmological models without the initial singularity only for flat universes; the results do not essentially depend on the equation of state. (author)
Topics in inflationary cosmologies
International Nuclear Information System (INIS)
Mahajan, S.
1986-04-01
Several aspects of inflationary cosmologies are discussed. An introduction to the standard hot big bang cosmological model is reviewed, and some of the problems associated with it are presented. A short review of the proposals for solving the cosmological conundrums of the big bang model is presented. Old and the new inflationary scenarios are discussed and shown to be unacceptable. Some alternative scenarios especially those using supersymmetry are reviewed briefly. A study is given of inflationary models where the same set of fields that breaks supersymmetry is also responsible for inflation. In these models, the scale of supersymmetry breaking is related to the slope of the potential near the origin and can thus be kept low. It is found that a supersymmetry breaking scale of the order of the weak breaking scale. The cosmology obtained from the simplest of such models is discussed in detail and it is shown that there are no particular problems except a low reheating temperature and a violation of the thermal constraint. A possible solution to the thermal constraint problem is given by introducing a second field, and the role played by this second field in the scenario is discussed. An alternative mechanism for the generation of baryon number within the framework of supergravity inflationary models is studied using the gravitational couplings of the heavy fields with the hidden sector (the sector which breaks supersymmetry). This mechanism is applied to two specific models - one with and one without supersymmetry breaking. The baryon to entropy ratio is found to be dependent on parameters which are model dependent. Finally, the effect of direct coupling between the two sectors on results is related, 88 refs., 6 figs
Vacuum inhomogeneous cosmological models
International Nuclear Information System (INIS)
Hanquin, J.-L.
1984-01-01
The author presents some results concerning the vacuum cosmological models which admit a 2-dimensional Abelian group of isometries: classifications of these space-times based on the topological nature of their space-like hypersurfaces and on their time evolution, analysis of the asymptotical behaviours at spatial infinity for hyperbolical models as well as in the neighbourhood of the singularity for the models possessing a time singularity during their evolution. (Auth.)
International Nuclear Information System (INIS)
Effenberger, R.
1974-09-01
The author summarizes some of the many questions and answers which have been raised over the years regarding the nature of matter, the origin of its forms and the associated concept of cosmology including the formation of the universe, our place in it and its course of evolution. An examination of the development of the classical concept of matter and its subsequent transformations within the space-time fields of relativity and quantum theory is also presented
International Nuclear Information System (INIS)
Wang Xiaomin; Tegmark, Max; Zaldarriaga, Matias
2002-01-01
We perform a detailed analysis of the latest cosmic microwave background (CMB) measurements (including BOOMERaNG, DASI, Maxima and CBI), both alone and jointly with other cosmological data sets involving, e.g., galaxy clustering and the Lyman Alpha Forest. We first address the question of whether the CMB data are internally consistent once calibration and beam uncertainties are taken into account, performing a series of statistical tests. With a few minor caveats, our answer is yes, and we compress all data into a single set of 24 bandpowers with associated covariance matrix and window functions. We then compute joint constraints on the 11 parameters of the 'standard' adiabatic inflationary cosmological model. Our best fit model passes a series of physical consistency checks and agrees with essentially all currently available cosmological data. In addition to sharp constraints on the cosmic matter budget in good agreement with those of the BOOMERaNG, DASI and Maxima teams, we obtain a heaviest neutrino mass range 0.04-4.2 eV and the sharpest constraints to date on gravity waves which (together with preference for a slight red-tilt) favor 'small-field' inflation models
Cosmological phase transitions
International Nuclear Information System (INIS)
Kolb, E.W.
1987-01-01
If the universe stated from conditions of high temperature and density, there should have been a series of phase transitions associated with spontaneous symmetry breaking. The cosmological phase transitions could have observable consequences in the present Universe. Some of the consequences including the formation of topological defects and cosmological inflation are reviewed here. One of the most important tools in building particle physics models is the use of spontaneous symmetry breaking (SSB). The proposal that there are underlying symmetries of nature that are not manifest in the vacuum is a crucial link in the unification of forces. Of particular interest for cosmology is the expectation that are the high temperatures of the big bang symmetries broken today will be restored, and that there are phase transitions to the broken state. The possibility that topological defects will be produced in the transition is the subject of this section. The possibility that the Universe will undergo inflation in a phase transition will be the subject of the next section. Before discussing the creation of topological defects in the phase transition, some general aspects of high-temperature restoration of symmetry and the development of the phase transition will be reviewed. 29 references, 1 figure, 1 table
International Nuclear Information System (INIS)
Amsterdamski, P.
1986-01-01
The standard cosmological model is reviewed and shown not to be self-sufficient in that it requires initial conditions most likely to be supplied by quantum cosmology. The possible approaches to the issue of initial conditions for cosmology are then discussed. In this thesis, the author considers three separate problems related to this issue. First, the possibility of inflation is investigated in detail by analyzing the evolution of metric perturbations and fluctuations in the expectation value of a scalar field prior to a phase transition; finite temperature effects are also included. Since the inhomogeneities were damped well before the onset of a phase transition. It is concluded that an inflation was possible. Next, the effective action of neutrino and photon fields is calculated for homogeneous spacetimes with small anisotropy; it is shown that quantum corrections to the action due to these fields influence the evolution of an early Universe in the Same way as do the analogous correction terms arising from a conformally invariant scalar which has been previously studied. Finally, the question of an early anisotropy is also discussed in a framework of Hartle-Hawking wave function of the Universe. A wave function of a Bianchi IX type Universe is calculated in a semiclassical approximation
International Nuclear Information System (INIS)
Desert, F.-Xavier
2004-01-01
After an introduction comprising some definitions, an historical overview, and a discussion of the paradoxical Universe, this course proposes a presentation of fundamental notions and theories, i.e. the restrained relativity and the universal gravitation. The next part addresses the general relativity with the following notions: space-time metrics and principle of generalised covariance, basics of tensor analysis, geodesics, energy-pulse tensor, curvature, Einstein equations, Newtonian limit, Schwarzschild metrics, gravitational waves, gravitational redshift. The next part addresses the standard cosmology with the Friedmann-Robertson-Walker metrics and the Friedmann-Lemaitre equations of the evolution of the Universe. The Universe expansion is then addressed: distances and horizons, Hubble law, determination of the Hubble constant. The next chapter deals with the constituents of the Universe: light matter, baryonic dark matter, black matter, supernovae, Universe acceleration and black energy. Then comes the nuclear evolution of the Universe: thermodynamics of the primordial Universe, the matter-antimatter asymmetry, from quarks to atoms, cosmic abundance, neutron cosmological background, matter-radiation equality, cosmo-chronology or the age of the Universe. The next chapter addresses the cosmological background at 3 K: sky electromagnetic spectrum, measurement of CMB anisotropies, interpretation of anisotropies, growth of perturbations. The last chapter addresses the quantum field theory and inflation: paradoxes of the standard Big Bang, the simple inflation, noticeable consequences
International Nuclear Information System (INIS)
Fliche, H.-H.; Souriau, J.-M.
1978-03-01
On the basis of colorimetric data a composite spectrum of quasars is established from the visible to the Lyman's limit. Its agreement with the spectrum of the quasar 3C273, obtained directly, confirms the homogeneity of these objects. The compatibility of the following hypotheses: negligible evolution of quasars, Friedmann type model of the universe with cosmological constant, is studied by means of two tests: a non-correlation test adopted to the observation conditions and the construction of diagrams (absolute magnitude, volume) using the K-correction deduced from the composite spectrum. This procedure happens to give relatively well-defined values of the parameters; the central values of the density parameter, the reduced curvature and the reduced cosmological constant are: Ω 0 =0.053, k 0 =0.245, lambda-zero=1.19, which correspond to a big bang model, eternally expanding, spatially finite, in which Hubble's parameter H is presently increasing. This model responds well to different cosmological tests: density of matter, diameter of radio sources, age of the universe. Its characteristics suggest various cosmogonic mechanisms, espacially mass formation by growth of empty spherical bubbles [fr
International Nuclear Information System (INIS)
Gelmini, G.B.
1996-01-01
These lectures are devoted to elementary particle physicists and assume the reader has very little or no knowledge of cosmology and astrophysics. After a brief historical introduction to the development of modern cosmology and astro-particles in which the Hot Big Bang model is defined, the Robertson-Walker metric and the dynamics of the Friedmann-Robertson-Walker cosmology are discussed in section 2. In section 3 the main observational features of the Universe are reviewed, including a description of our neighborhood, homogeneity and isotropy, the cosmic background radiation, the expansion, the age and the matter content of the Universe. A brief account of the thermal history of the Universe follows in section 4, and relic abundances are discussed in section 5. Section 6 is devoted to primordial nucleosynthesis, section 7 to structure formation in the Universe and section 8 to the possibility of detection of the dark matter in the halo of our galaxy. In the relevant sections recent developments are included, such as several so called open-quote open-quote crisis close-quote close-quote (the age crisis, the cluster baryon crisis and the nucleosynthesis crisis), and the MACHO events that may constitute the first detection of dark matter in the halo of our galaxy. copyright 1996 American Institute of Physics
International Nuclear Information System (INIS)
Gelmini, Graciela B.
1996-01-01
These lectures are devoted to elementary particle physicists and assume the reader has very little or no knowledge of cosmology and astrophysics. After a brief historical introduction to the development of modern cosmology and astro-particles in which the Hot Big Bang model is defined, the Robertson-Walker metric and the dynamics of the Friedmann-Robertson-Walker cosmology are discussed in section 2. In section 3 the main observational features of the Universe are reviewed, including a description of our neighborhood, homogeneity and isotropy, the cosmic background radiation, the expansion, the age and the matter content of the Universe. A brief account of the thermal history of the Universe follows in section 4, and relic abundances are discussed in section 5. Section 6 is devoted to primordial nucleosynthesis, section 7 to structure formation in the Universe and section 8 to the possibility of detection of the dark matter in the halo of our galaxy. In the relevant sections recent developments are included, such as several so called ''crisis'' (the age crisis, the cluster baryon crisis and the nucleosynthesis crisis), and the MACHO events that may constitute the first detection of dark matter in the halo of our galaxy
Cosmological perturbations in antigravity
Oltean, Marius; Brandenberger, Robert
2014-10-01
We compute the evolution of cosmological perturbations in a recently proposed Weyl-symmetric theory of two scalar fields with oppositely signed conformal couplings to Einstein gravity. It is motivated from the minimal conformal extension of the standard model, such that one of these scalar fields is the Higgs while the other is a new particle, the dilaton, introduced to make the Higgs mass conformally symmetric. At the background level, the theory admits novel geodesically complete cyclic cosmological solutions characterized by a brief period of repulsive gravity, or "antigravity," during each successive transition from a big crunch to a big bang. For simplicity, we consider scalar perturbations in the absence of anisotropies, with potential set to zero and without any radiation. We show that despite the necessarily wrong-signed kinetic term of the dilaton in the full action, these perturbations are neither ghostlike nor tachyonic in the limit of strongly repulsive gravity. On this basis, we argue—pending a future analysis of vector and tensor perturbations—that, with respect to perturbative stability, the cosmological solutions of this theory are viable.
International Nuclear Information System (INIS)
Anchordoqui, Luis; Nawata, Satoshi; Goldberg, Haim; Nunez, Carlos
2007-01-01
We explore the cosmological content of Salam-Sezgin six-dimensional supergravity, and find a solution to the field equations in qualitative agreement with observation of distant supernovae, primordial nucleosynthesis abundances, and recent measurements of the cosmic microwave background. The carrier of the acceleration in the present de Sitter epoch is a quintessence field slowly rolling down its exponential potential. Intrinsic to this model is a second modulus which is automatically stabilized and acts as a source of cold dark matter, with a mass proportional to an exponential function of the quintessence field (hence realizing varying mass particle models within a string context). However, any attempt to saturate the present cold dark matter component in this manner leads to unacceptable deviations from cosmological data--a numerical study reveals that this source can account for up to about 7% of the total cold dark matter budget. We also show that (1) the model will support a de Sitter energy in agreement with observation at the expense of a miniscule breaking of supersymmetry in the compact space; (2) variations in the fine structure constant are controlled by the stabilized modulus and are negligible; (3) ''fifth'' forces are carried by the stabilized modulus and are short range; (4) the long time behavior of the model in four dimensions is that of a Robertson-Walker universe with a constant expansion rate (w=-1/3). Finally, we present a string theory background by lifting our six-dimensional cosmological solution to ten dimensions
Inflation and quantum cosmology
International Nuclear Information System (INIS)
Linde, A.
1990-01-01
We investigate an interplay between elementary particle physics, quantum cosmology and inflation. These results obtained within this approach are compared with the results obtained in the context of Euclidean quantum cosmology. In particular, we discuss relations between the stochastic approach to inflationary cosmology and the approaches based on the investigation of the Hartle-Hawking and tunneling wave functions of the universe. We argue that neither of these wave functions can be used for a complete description of the inflationary universe, but in certain cases they can be used for a description of some particular stages of inflation. It is shown that if the present vacuum energy density ρ υ exceeds some extremely small critical value ρ c (ρ c ∼ 10 -107 ) g cm -3 for chaotic inflation in the theory 1/2m 2 φ 2 ), then the lifetime of mankind in the inflationary universe should be finite, even though the universe as a whole will exist without end. A possible way to justify the anthropic principle in the context of the baby universe theory and to apply it to the evaluation of masses of elementary particles, of their coupling constants and of the vacuum energy density is also discussed. (author)
A varying-α brane world cosmology
International Nuclear Information System (INIS)
Youm, Donam
2001-08-01
We study the brane world cosmology in the RS2 model where the electric charge varies with time in the manner described by the varying fine-structure constant theory of Bekenstein. We map such varying electric charge cosmology to the dual variable-speed-of-light cosmology by changing system of units. We comment on cosmological implications for such cosmological models. (author)
The Future of Theoretical Physics and Cosmology
Gibbons, G. W.; Shellard, E. P. S.; Rankin, S. J.
2009-08-01
Preface; List of contributors; 1. Introduction; Part I. Popular Symposium: 2. Our complex cosmos and its future Martin J. Rees; 3. Theories of everything and Hawking's wave function of the Universe James B. Hartle; 4. The problem of space-time singularities: implications for quantum gravity? Roger Penrose; 5. Warping spacetime Kip Thorne; 6. 60 years in a nutshell Stephen W. Hawking; Part II. Spacetime Singularities: 7. Cosmological perturbations and singularities George F. R. Ellis; 8. The quantum physics of chronology protection Matt Visser; 9. Energy dominance and the Hawking-Ellis vacuum conservation theorem Brandon Carter; 10. On the instability of extra space dimensions Roger Penrose; Part III. Black Holes: 11. Black hole uniqueness and the inner horizon stability problem Werner Israel; 12. Black holes in the real universe and their prospects as probes of relativistic gravity Martin J. Rees; 13. Primordial black holes Bernard Carr; 14. Black hole pair creation Simon F. Ross; 15. Black holes as accelerators Steven Giddings; Part IV. Hawking Radiation: 16. Black holes and string theory Malcolm Perry; 17. M theory and black hole quantum mechanics Joe Polchinski; 18. Playing with black strings Gary Horowitz; 19. Twenty years of debate with Stephen Leonard Susskind; Part V. Quantum Gravity: 20. Euclidean quantum gravity: the view from 2002 Gary Gibbons; 21. Zeta functions, anomalies and stable branes Ian Moss; 22. Some reflections on the status of conventional quantum theory when applied to quantum gravity Chris Isham; 23. Quantum geometry and its ramifications Abhay Ashtekar; 24. Topology change in quantum gravity Fay Dowker; Part VI. M Theory and Beyond: 25. The past and future of string theory Edward Witten; 26. String theory David Gross; 27. A brief description of string theory Michael Green; 28. The story of M Paul Townsend; 29. Gauged supergravity and holographic field theory Nick Warner; 30. 57 varieties in a NUTshell Chris Pope; Part VII. de Sitter Space
Bias-limited extraction of cosmological parameters
Energy Technology Data Exchange (ETDEWEB)
Shimon, Meir; Itzhaki, Nissan; Rephaeli, Yoel, E-mail: meirs@wise.tau.ac.il, E-mail: nitzhaki@post.tau.ac.il, E-mail: yoelr@wise.tau.ac.il [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)
2013-03-01
It is known that modeling uncertainties and astrophysical foregrounds can potentially introduce appreciable bias in the deduced values of cosmological parameters. While it is commonly assumed that these uncertainties will be accounted for to a sufficient level of precision, the level of bias has not been properly quantified in most cases of interest. We show that the requirement that the bias in derived values of cosmological parameters does not surpass nominal statistical error, translates into a maximal level of overall error O(N{sup −½}) on |ΔP(k)|/P(k) and |ΔC{sub l}|/C{sub l}, where P(k), C{sub l}, and N are the matter power spectrum, angular power spectrum, and number of (independent Fourier) modes at a given scale l or k probed by the cosmological survey, respectively. This required level has important consequences on the precision with which cosmological parameters are hoped to be determined by future surveys: in virtually all ongoing and near future surveys N typically falls in the range 10{sup 6}−10{sup 9}, implying that the required overall theoretical modeling and numerical precision is already very high. Future redshifted-21-cm observations, projected to sample ∼ 10{sup 14} modes, will require knowledge of the matter power spectrum to a fantastic 10{sup −7} precision level. We conclude that realizing the expected potential of future cosmological surveys, which aim at detecting 10{sup 6}−10{sup 14} modes, sets the formidable challenge of reducing the overall level of uncertainty to 10{sup −3}−10{sup −7}.
Testing cosmology with galaxy clusters
DEFF Research Database (Denmark)
Rapetti Serra, David Angelo
2011-01-01
PASCOS 2011 will be held in Cambridge UK. The conference will be hosted by the Centre for Theoretical Cosmology (DAMTP) at the Mathematical Sciences site in the University of Cambridge. The aim of the conference is to explore and develop synergies between particle physics, string theory and cosmo......PASCOS 2011 will be held in Cambridge UK. The conference will be hosted by the Centre for Theoretical Cosmology (DAMTP) at the Mathematical Sciences site in the University of Cambridge. The aim of the conference is to explore and develop synergies between particle physics, string theory...... and cosmology. There will be an emphasis on timely interdisciplinary topics: • critical tests of inflationary cosmology • advances in fundamental cosmology • applications of string theory (AdS/CMT) • particle and string phenomenology • new experimental particle physics results • and cosmological probes...
Benoit-Lévy, Aurélien; Chardin, Gabriel
2014-05-01
We study an unconventional cosmology, in which we investigate the consequences that antigravity would pose to cosmology. We present the main characteristics of the Dirac-Milne Universe, a cosmological model where antimatter has a negative active gravitational mass. In this non-standard Universe, separate domains of matter and antimatter coexist at our epoch without annihilation, separated by a gravitationally induced depletion zone. We show that this cosmology does not require a priori the Dark Matter and Dark Energy components of the standard model of cosmology. Additionally, inflation becomes an unnecessary ingredient. Investigating this model, we show that the classical cosmological tests such as primordial nucleosynthesis, Type Ia supernovæ and Cosmic Microwave Background are surprisingly concordant.
International Nuclear Information System (INIS)
Tkachev, Igor
1993-01-01
When the common ground between particle physics, astrophysics and cosmology started to become a developing area, the Institute for Nuclear Research (INR) of the Russian Academy of Sciences had the foresight in 1981 to institute the Baksan Schools on Particles and Cosmology. This now traditional event, held biannually in the Baksan Valley, has gone on to attract international participation. The site is close to the INR Baksan Neutrino Observatory with its underground and surface installations, including the SAGE gallium solar neutrino detector, the Underground Scintillation Telescope, and the 'Carpet' extensive air shower array. Participation is mainly from experimentalists working in non accelerator particle physics and particle astrophysics. The most recent School, held from April 21 to 28, began with an opening address by INR Director V. A. Matveev. J.Frieman reviewed standard big bang cosmology, emphasizing how the recent COBE results and the observations of large scale galaxy clustering fit into a standard cosmology framework. For inflationary cosmology, he showed how different models may be tested through their predictions for large-scale galactic structure and for cosmic microwave background anisotropy. A.Stebbins presented details of the large scale distribution of galaxies which, combined with velocity information and microwave background anisotropy data, provide strong constraints on theories of the origin of primordial inhomogeneities. Inflation requires, and theories of the large scale structure strongly favour the critical value for the cosmic mass density, while, as D.Seckel explained in his lecture on nucleosynthesis and abundances of the light elements, the baryon contribution to this density has to be tens of times smaller. A general review on the observational evidence for dark matter, dark matter particle candidates and the strategy of dark matter searches was given by I. Tkachev, who stressed the gravitational microlensing MACHO
Conformal Cosmology and Supernova Data
Behnke, Danilo; Blaschke, David; Pervushin, Victor; Proskurin, Denis
2000-01-01
We define the cosmological parameters $H_{c,0}$, $\\Omega_{m,c}$ and $\\Omega_{\\Lambda, c}$ within the Conformal Cosmology as obtained by the homogeneous approximation to the conformal-invariant generalization of Einstein's General Relativity theory. We present the definitions of the age of the universe and of the luminosity distance in the context of this approach. A possible explanation of the recent data from distant supernovae Ia without a cosmological constant is presented.
Cosmology for high energy physicists
International Nuclear Information System (INIS)
Albrecht, A.
1987-11-01
The standard big bang model of cosmology is presented. Although not perfect, its many successes make it a good starting point for most discussions of cosmology. Places are indicated where well understood laboratory physics is incorporated into the big bang, leading to successful predictions. Much less established aspects of high energy physics and some of the new ideas they have introduced into the field of cosmology are discussed, such as string theory, inflation and monopoles. 49 refs., 5 figs
Stability of the Einstein static universe in open cosmological models
International Nuclear Information System (INIS)
Canonico, Rosangela; Parisi, Luca
2010-01-01
The stability properties of the Einstein static solution of general relativity are altered when corrective terms arising from modification of the underlying gravitational theory appear in the cosmological equations. In this paper the existence and stability of static solutions are considered in the framework of two recently proposed quantum gravity models. The previously known analysis of the Einstein static solutions in the semiclassical regime of loop quantum cosmology with modifications to the gravitational sector is extended to open cosmological models where a static neutrally stable solution is found. A similar analysis is also performed in the framework of Horava-Lifshitz gravity under detailed balance and projectability conditions. In the case of open cosmological models the two solutions found can be either unstable or neutrally stable according to the admitted values of the parameters.
Energy Technology Data Exchange (ETDEWEB)
Grattidge, W.; Westbrook, J.; McCarthy, J.; Northrup, C. Jr.; Rumble, J. Jr.
1986-01-01
This report documents the initial phases of the Materials Information for Science and Technology (MIST) project jointly supported by the Department of Energy and the National Bureau of Standards. The purpose of MIST is to demonstrate the power and utility of computer access to materials property data. The initial goals include: to exercise the concept of a computer network of materials databases and to build a demonstration of such a system suitable for use as the core of operational systems in the future. Phases I and II are described in detail herein. In addition, a discussion is given of the expected usage of the system. The primary MIST prototype project is running on an IBM 3084 under STS at the Stanford University's Information Technology Services (ITS). Users can access the Stanford system via ARPANET, TELENET, and TYMNET, as well as via commercial telephone lines. For fastest response time and use of the full screen PRISM interface, direct connection using a 2400 baud modem with the MNP error-correcting protocol over standard telephone lines gives the best results - though slower speed connections and a line-oriented interface are also available. This report gives detailed plans regarding the properties to be enterend and the materials to be entered into the system.
Energy Technology Data Exchange (ETDEWEB)
Stovall, Stacey H.
1994-08-01
The Idaho Water Rental Pilot Project was implemented in 1991 as part of the Non-Treaty Storage Fish and Wildlife Agreement between Bonneville Power Administration and the Columbia Basin Fish and Wildlife Authority. The goal of the project is to quantify resident fish and wildlife impacts resulting from salmon flow augmentation releases made from the upper Snake River Basin. Phase I summarized existing resource information and provided management recommendations to protect and enhance resident fish and wildlife habitat resulting from storage releases for the I improvement of an adromous fish migration. Phase II includes the following: (1) a summary of recent biological, legal, and political developments within the basin as they relate to water management issues, (2) a biological appraisal of the Snake River between American Falls Reservoir and the city of Blackfoot to examine the effects of flow fluctuation on fish and wildlife habitat, and (3) a preliminary accounting of 1993--1994 flow augmentation releases out of the upper Snake, Boise, and Payette river systems. Phase III will include the development of a model in which annual flow requests and resident fish and wildlife suitability information are interfaced with habitat time series analysis to provide an estimate of resident fish and wildlife resources.
The PEP-II/BaBar Project-Wide Database using World Wide Web and Oracle*Case
International Nuclear Information System (INIS)
Chan, A.; Crane, G.; MacGregor, I.; Meyer, S.
1995-12-01
The PEP-II/BaBar Project Database is a tool for monitoring the technical and documentation aspects of the accelerator and detector construction. It holds the PEP-II/BaBar design specifications, fabrication and installation data in one integrated system. Key pieces of the database include the machine parameter list, components fabrication and calibration data, survey and alignment data, property control, CAD drawings, publications and documentation. This central Oracle database on a UNIX server is built using Oracle*Case tools. Users at the collaborating laboratories mainly access the data using World Wide Web (WWW). The Project Database is being extended to link to legacy databases required for the operations phase
Perturbations in loop quantum cosmology
International Nuclear Information System (INIS)
Nelson, W; Agullo, I; Ashtekar, A
2014-01-01
The era of precision cosmology has allowed us to accurately determine many important cosmological parameters, in particular via the CMB. Confronting Loop Quantum Cosmology with these observations provides us with a powerful test of the theory. For this to be possible, we need a detailed understanding of the generation and evolution of inhomogeneous perturbations during the early, quantum gravity phase of the universe. Here, we have described how Loop Quantum Cosmology provides a completion of the inflationary paradigm, that is consistent with the observed power spectra of the CMB
An introduction to modern cosmology
Liddle, Andrew
2015-01-01
An Introduction to Modern Cosmology Third Edition is an accessible account of modern cosmological ideas. The Big Bang Cosmology is explored, looking at its observational successes in explaining the expansion of the Universe, the existence and properties of the cosmic microwave background, and the origin of light elements in the universe. Properties of the very early Universe are also covered, including the motivation for a rapid period of expansion known as cosmological inflation. The third edition brings this established undergraduate textbook up-to-date with the rapidly evolving observation
Cosmological Reflection of Particle Symmetry
Directory of Open Access Journals (Sweden)
Maxim Khlopov
2016-08-01
Full Text Available The standard model involves particle symmetry and the mechanism of its breaking. Modern cosmology is based on inflationary models with baryosynthesis and dark matter/energy, which involves physics beyond the standard model. Studies of the physical basis of modern cosmology combine direct searches for new physics at accelerators with its indirect non-accelerator probes, in which cosmological consequences of particle models play an important role. The cosmological reflection of particle symmetry and the mechanisms of its breaking are the subject of the present review.
Bojowald, Martin
2008-01-01
Quantum gravity is expected to be necessary in order to understand situations in which classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical spacetime inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding spacetime is then modified. One particular theory is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. The main effects are introduced into effective classical equations, which allow one to avoid the interpretational problems of quantum theory. They give rise to new kinds of early-universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function, which allows an extension of quantum spacetime beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of spacetime arising in loop quantum gravity and its application to cosmology sheds light on more general issues, such as the nature of time. Supplementary material is available for this article at 10.12942/lrr-2008-4.
Directory of Open Access Journals (Sweden)
Bojowald Martin
2008-07-01
Full Text Available Quantum gravity is expected to be necessary in order to understand situations in which classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical spacetime inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding spacetime is then modified. One particular theory is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. The main effects are introduced into effective classical equations, which allow one to avoid the interpretational problems of quantum theory. They give rise to new kinds of early-universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function, which allows an extension of quantum spacetime beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of spacetime arising in loop quantum gravity and its application to cosmology sheds light on more general issues, such as the nature of time.
Directory of Open Access Journals (Sweden)
Bojowald Martin
2005-12-01
Full Text Available Quantum gravity is expected to be necessary in order to understand situations where classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical space-time inevitably comes to an end after a finite amount of proper time. This presents a breakdown of the classical picture and requires an extended theory for a meaningful description. Since small length scales and high curvatures are involved, quantum effects must play a role. Not only the singularity itself but also the surrounding space-time is then modified. One particular realization is loop quantum cosmology, an application of loop quantum gravity to homogeneous systems, which removes classical singularities. Its implications can be studied at different levels. Main effects are introduced into effective classical equations which allow to avoid interpretational problems of quantum theory. They give rise to new kinds of early universe phenomenology with applications to inflation and cyclic models. To resolve classical singularities and to understand the structure of geometry around them, the quantum description is necessary. Classical evolution is then replaced by a difference equation for a wave function which allows to extend space-time beyond classical singularities. One main question is how these homogeneous scenarios are related to full loop quantum gravity, which can be dealt with at the level of distributional symmetric states. Finally, the new structure of space-time arising in loop quantum gravity and its application to cosmology sheds new light on more general issues such as time.
Cosmology from quantum potential
Energy Technology Data Exchange (ETDEWEB)
Farag Ali, Ahmed, E-mail: ahmed.ali@fsc.bu.edu.eg [Center for Fundamental Physics, Zewail City of Science and Technology, Giza, 12588 (Egypt); Dept. of Physics, Faculty of Sciences, Benha University, Benha, 13518 (Egypt); Das, Saurya, E-mail: saurya.das@uleth.c [Department of Physics and Astronomy, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada)
2015-02-04
It was shown recently that replacing classical geodesics with quantal (Bohmian) trajectories gives rise to a quantum corrected Raychaudhuri equation (QRE). In this article we derive the second order Friedmann equations from the QRE, and show that this also contains a couple of quantum correction terms, the first of which can be interpreted as cosmological constant (and gives a correct estimate of its observed value), while the second as a radiation term in the early universe, which gets rid of the big-bang singularity and predicts an infinite age of our universe.
Wilczek, Frank; Turner, Michael S.
1990-09-01
If Peccei-Quinn (PQ) symmetry is broken after inflation, the initial axion angle is a random variable on cosmological scales; based on this fact, estimates of the relic-axion mass density give too large a value if the axion mass is less than about 10-6 eV. This bound can be evaded if the Universe underwent inflation after PQ symmetry breaking and if the observable Universe happens to be a region where the initial axion angle was atypically small, .1 . (ma/10-6eV)0.59. We show consideration of fluctuations induced during inflation severely constrains the latter alternative.
International Nuclear Information System (INIS)
Turner, M.S.; Wilczek, F.
1991-01-01
If Peccei-Quinn (PQ) symmetry is broken after inflation, the initial axion angle is a random variable on cosmological scales; based on this fact, estimates of the relic-axion mass density give too large a value if the axion mass is less than about 10 -6 eV. This bound can be evaded if the Universe underwent inflation after PQ symmetry breaking and if the observable Universe happens to be a region where the initial axion angle was atypically small, θ 1 approx-lt[m a /10 -6 eV 0.59 .] We show consideration of fluctuations induced during inflation severely constrains the latter alternative
Wright, Rosemary
1995-01-01
The popularity of Stephen Hawking's work has put cosmology back in the public eye. The question of how the universe began, and why it hangs together, still puzzles scientists. Their puzzlement began two and a half thousand years ago when Greek philosophers first 'looked up at the sky and formed a theory of everything.' Though their solutions are little credited today, the questions remain fresh.The early Greek thinkers struggled to come to terms with and explain the totality of their surroundings; to identitify an original substance from which the universe was compounded; and to reconcil
Leibundgut, B.; Sullivan, M.
2018-03-01
The primary agent for Type Ia supernova cosmology is the uniformity of their appearance. We present the current status, achievements and uncertainties. The Hubble constant and the expansion history of the universe are key measurements provided by Type Ia supernovae. They were also instrumental in showing time dilation, which is a direct observational signature of expansion. Connections to explosion physics are made in the context of potential improvements of the quality of Type Ia supernovae as distance indicators. The coming years will see large efforts to use Type Ia supernovae to characterise dark energy.
International Nuclear Information System (INIS)
Kleinschmidt, Axel; Nicolai, Hermann
2006-01-01
We construct simple exact solutions to the E 10 /K(E 10 ) coset model by exploiting its integrability. Using the known correspondences with the bosonic sectors of maximal supergravity theories, these exact solutions translate into exact cosmological solutions. In this way, we are able to recover some recently discovered solutions of M-theory exhibiting phases of accelerated expansion, or, equivalently, S-brane solutions, and thereby accommodate such solutions within the E 10 /K(E 10 ) model. We also discuss the situation regarding solutions with non-vanishing (constant) curvature of the internal manifold
Quintessential brane cosmology
International Nuclear Information System (INIS)
Kunze, K.E.; Vazquez-Mozo, M.A.
2002-01-01
We study a class of braneworlds where the cosmological evolution arises as the result of the movement of a three-brane in a five-dimensional static dilatonic bulk, with and without reflection symmetry. The resulting four-dimensional Friedmann equation includes a term which, for a certain range of the parameters, effectively works as a quintessence component, producing an acceleration of the universe at late times. Using current observations and bounds derived from big-bang nucleosynthesis, we estimate the parameters that characterize the model
Particle physics and cosmology
International Nuclear Information System (INIS)
Srednicki, M.
1990-01-01
At least eighty percent of the mass of the universe consists of some material which, unlike ordinary matter, neither emits nor absorbs light. This book collects key papers related to the discovery of this astonishing fact and its profound implications for astrophysics, cosmology, and the physics of elementary particles. The book focusses on the likely possibility that the dark matter is composed of an as yet undiscovered elementary particle, and examines the boundaries of our present knowledge of the properties such a particle must possess. (author). refs.; figs.; tabs
Cosmological effects of nonlinear electrodynamics
International Nuclear Information System (INIS)
Novello, M; Goulart, E; Salim, J M; Bergliaffa, S E Perez
2007-01-01
It will be shown that a given realization of nonlinear electrodynamics, used as a source of Einstein's equations, generates a cosmological model with interesting features, namely a phase of current cosmic acceleration, and the absence of an initial singularity, thus pointing to a way of solving two important problems in cosmology
Quantum Gravity Effects in Cosmology
Directory of Open Access Journals (Sweden)
Gu Je-An
2018-01-01
Full Text Available Within the geometrodynamic approach to quantum cosmology, we studied the quantum gravity effects in cosmology. The Gibbons-Hawking temperature is corrected by quantum gravity due to spacetime fluctuations and the power spectrum as well as any probe field will experience the effective temperature, a quantum gravity effect.
Neutrino physics and precision cosmology
DEFF Research Database (Denmark)
Hannestad, Steen
2016-01-01
I review the current status of structure formation bounds on neutrino properties such as mass and energy density. I also discuss future cosmological bounds as well as a variety of different scenarios for reconciling cosmology with the presence of light sterile neutrinos....
Modified General Relativity and Cosmology
Abdel-Rahman, A.-M. M.
1997-10-01
Aspects of the modified general relativity theory of Rastall, Al-Rawaf and Taha are discussed in both the radiation- and matter-dominated flat cosmological models. A nucleosynthesis constraint on the theory's free parameter is obtained and the implication for the age of the Universe is discussed. The consistency of the modified matter- dominated model with the neoclassical cosmological tests is demonstrated.
Vignettes in Gravitation and Cosmology
Sriramkumar, L
2012-01-01
This book comprises expository articles on different aspects of gravitation and cosmology that are aimed at graduate students. The topics discussed are of contemporary interest assuming only an elementary introduction to gravitation and cosmology. The presentations are to a certain extent pedagogical in nature, and the material developed is not usually found in sufficient detail in recent textbooks in these areas.
Kerr metric in cosmological background
Energy Technology Data Exchange (ETDEWEB)
Vaidya, P C [Gujarat Univ., Ahmedabad (India). Dept. of Mathematics
1977-06-01
A metric satisfying Einstein's equation is given which in the vicinity of the source reduces to the well-known Kerr metric and which at large distances reduces to the Robertson-Walker metric of a nomogeneous cosmological model. The radius of the event horizon of the Kerr black hole in the cosmological background is found out.
Introduction to gravity and cosmology
International Nuclear Information System (INIS)
Jauneau, L.
1988-09-01
Relativity principles, equivalence principles, and the general covariance principle are introduced. Curved space analysis via tensor calculus and absolute differential calculus is outlined. Einstein's equations are presented. The Schwarzschild solution; tests of general relativity; and black holes are discussed. Application of general relativity to cosmology is considered. The Standard Model of cosmology and its extensions are reviewed
Highlights in gravitation and cosmology
International Nuclear Information System (INIS)
Iyer, B.R.; Kembhavi, Ajit; Narlikar, J.V.; Vishveshwara, C.V.
1988-01-01
This book assesses research into gravitation and cosmology by examining the subject from various viewpoints: the classical and quantum pictures, along with the cosmological and astrophysical applications. There are 35 articles by experts of international standing. Each defines the state of the art and contains a concise summary of our present knowledge of a facet of gravitational physics. These edited papers are based on those first given at an international conference held in Goa, India at the end of 1987. The following broad areas are covered: classical relativity, quantum gravity, cosmology, black holes, compact objects, gravitational radiation and gravity experiments. In this volume there are also summaries of discussions on the following special topics: exact solutions of cosmological equations, mathematical aspects of general relativity, the early universe, and quantum gravity. For research workers in cosmology and gravitation this reference book provides a broad view of present achievements and current problems. (author)
Is the cosmological singularity compulsory
International Nuclear Information System (INIS)
Bekenstein, J.D.; Meisels, A.
1980-01-01
The cosmological singularity is inherent in all conventional general relativistic cosmological models. There can be no question that it is an unphysical feature; yet there does not seem to be any convervative way of eliminating it. Here we present singularity-free isotropic cosmological models which are indistinguishable from general relativistic ones at late times. They are based on the general theory of variable rest masses that we developed recently. Outside cosmology this theory simulates general relativity well. Thus it provides a framework incorporating those features which have made geneal relativity so sucessful while providing a way out of singularity dilemma. The cosmological models can be made to incorporate Dirac's large numbers hypothesis. G(now)/G(0)approx.10 -38
Higher dimensional loop quantum cosmology
International Nuclear Information System (INIS)
Zhang, Xiangdong
2016-01-01
Loop quantum cosmology (LQC) is the symmetric sector of loop quantum gravity. In this paper, we generalize the structure of loop quantum cosmology to the theories with arbitrary spacetime dimensions. The isotropic and homogeneous cosmological model in n + 1 dimensions is quantized by the loop quantization method. Interestingly, we find that the underlying quantum theories are divided into two qualitatively different sectors according to spacetime dimensions. The effective Hamiltonian and modified dynamical equations of n + 1 dimensional LQC are obtained. Moreover, our results indicate that the classical big bang singularity is resolved in arbitrary spacetime dimensions by a quantum bounce. We also briefly discuss the similarities and differences between the n + 1 dimensional model and the 3 + 1 dimensional one. Our model serves as a first example of higher dimensional loop quantum cosmology and offers the possibility to investigate quantum gravity effects in higher dimensional cosmology. (orig.)
International Nuclear Information System (INIS)
Lachieze-Rey, Marc
2005-01-01
After having recalled that the Platonist and Aristotelian views were the basis of cosmology during the Antiquity and the Middle-Age, the author indicates that these views have been put into question again by Copernicus, Giordano Bruno, Kepler, Galileo and others whose works resulted in Newton physics. The author then follows and comments this history with the emergence of contemporary physics (relativistic and quantum physics) and new concepts for matter, space and time, light, energy, and the Universe with a relativistic cosmology. After having commented these last issues, the author evokes how new results confirmed big-bang models. He also outlines problems to be solved or addressed: observations related to the hidden mass, issue of unification, technological issues to obtain information about what went on more than 13 billions years ago. The author comments the issue of other universes, and issues regarding science, metaphysics and religion raised by these theoretical developments. He also comments the emergence of new physics (supersymmetry, quantum gravity)
Topics in inflationary cosmology
International Nuclear Information System (INIS)
Kahn, R.N.
1985-01-01
This thesis examines several topics in the theory of inflationary cosmology. It first proves the existence of Hawking Radiation during the slow-rolling period of a new inflationary universe. It then derives and somewhat extends Bardeen's gauge invariant formalism for calculating the growth of linear gravitational perturbations in a Friedmann-Robertson-Walker cosmological background. This formalism is then applied, first to several new inflationary universe models all of which show a Zel'dovich spectrum of fluctuations, but with amplitude sigma(100 4 ) above observational limits. The general formalism is next applied to models that exhibit primordial inflation. Fluctuations in these models also exhibit a Zel'dovich spectrum here with an acceptable amplitude. Finally the thesis presents the results of new, numerical calculations. A classical, (2 + 1) dimensional computer model is developed that includes a Higgs field (which drives inflation) along with enough auxiliary fields to generate dynamically not only a thermal bath, but also the fluctuations that naturally accompany that bath. The thesis ends with a discussion of future prospects
Green, Dan
2016-01-01
This volume makes explicit use of the synergy between cosmology and high energy physics, for example, supersymmetry and dark matter, or nucleosynthesis and the baryon-to-photon ratio. In particular the exciting possible connection between the recently discovered Higgs scalar and the scalar field responsible for inflation is explored.The recent great advances in the accuracy of the basic cosmological parameters is exploited in that no free scale parameters such as h appear, rather the basic calculations are done numerically using all sources of energy density simultaneously. Scripts are provided that allow the reader to calculate exact results for the basic parameters. Throughout MATLAB tools such as symbolic math, numerical solutions, plots and 'movies' of the dynamical evolution of systems are used. The GUI package is also shown as an example of the real time manipulation of parameters which is available to the reader.All the MATLAB scripts are made available to the reader to explore examples of the uses of ...
Indian cosmogonies and cosmologies
Directory of Open Access Journals (Sweden)
Pajin Dušan
2011-01-01
Full Text Available Various ideas on how the universe appeared and develops, were in Indian tradition related to mythic, religious, or philosophical ideas and contexts, and developed during some 3.000 years - from the time of Vedas, to Puranas. Conserning its appeareance, two main ideas were presented. In one concept it appeared out of itself (auto-generated, and gods were among the first to appear in the cosmic sequences. In the other, it was a kind of divine creation, with hard work (like the dismembering of the primal Purusha, or as emanation of divine dance. Indian tradition had also various critiques of mythic and religious concepts (from the 8th c. BC, to the 6c., who favoured naturalistic and materialistic explanations, and concepts, in their cosmogony and cosmology. One the peculiarities was that indian cosmogony and cosmology includes great time spans, since they used a digit system which was later (in the 13th c. introduced to Europe by Fibonacci (Leonardo of Pisa, 1170-1240.
Particle physics and cosmology
International Nuclear Information System (INIS)
Kolb, E.W.
1986-10-01
This series of lectures is about the role of particle physics in physical processes that occurred in the very early stages of the bug gang. Of particular interest is the role of particle physics in determining the evolution of the early Universe, and the effect of particle physics on the present structure of the Universe. The use of the big bang as a laboratory for placing limits on new particle physics theories will also be discussed. Section 1 reviews the standard cosmology, including primordial nucleosynthesis. Section 2 reviews the decoupling of weakly interacting particles in the early Universe, and discusses neutrino cosmology and the resulting limits that may be placed on the mass and lifetime of massive neutrinos. Section 3 discusses the evolution of the vacuum through phase transitions in the early Universe and the formation of topological defects in the transitions. Section 4 covers recent work on the generation of the baryon asymmetry by baryon-number violating reactions in Grand Unified Theories, and mentions some recent work on baryon number violation effects at the electroweak transition. Section 5 is devoted to theories of cosmic inflation. Finally, Section 6 is a discussion of the role of extra spatial dimensions in the evolution of the early Universe. 78 refs., 32 figs., 6 tabs
Perkins, D. K.
2006-08-01
Microbes swarming on a sand grain planet or integral complex organisms evolving consciousness at the forefront of cosmic evolution? How is our new cosmology contributing to redefining who we see ourselves to be at the edge of the 21^st century, as globalization and capitalism speed forward? How is the evolution of stardust and the universe offering new paradigms of process and identity regarding the role, function and emergence of life in space-time? What are the cultural and philosophical questions that are arising and how might astronomy be contributing to the creation of new visions for cooperation and community at a global scale? What is the significance of including astronomy in K-12 education and what can it offer youth regarding values in light of the present world situation? Exploring our new cosmological concepts and the emergence of life at astronomical scales may offer much of valuable orientation toward reframing the human role in global evolution. Considering new insight from astrobiology each diverse species has a definitive role to play in the facilitation and functioning of the biosphere. Thus the question may arise: Is there any sort of ethic implied by natural science and offered by our rapidly expanding cosmic frontier?
Cosmology and particle physics
International Nuclear Information System (INIS)
Salati, P.
1986-01-01
If the hot Big Bang model is correct, the very early universe provides us with a good laboratory to test our ideas on particle physics. The temperature and the density at that time are so high that each known particle must exist in chemical and in thermal equilibrium with the others. When the universe cools, the particles freeze out, leaving us today with a cosmic background. Such a kind of relic is of great interest because we can probe the Big Bang Model by studying the fossilized gas of a known particle. Conversely we can use that model to derive information about a hypothetical particle. Basically the freezing of a gas occurs a temperature T o and may be thermal or chemical. Studying the decoupling of a stable neutrino brings information on its mass: if the mass M ν lies in the forbidden range, the neutrino has to be unstable and its lifetime is constrained by cosmology. As for the G.U.T. Monopole, cosmology tells us that its present mass density is either to big or to small (1 monopole/observable universe) owing to a predicted flux far from the Parker Limit. Finally, the super red-giant star life time constrains the axion or the Higgs to be more massive than .2 MeV [fr
Scalar cosmological perturbations
International Nuclear Information System (INIS)
Uggla, Claes; Wainwright, John
2012-01-01
Scalar perturbations of Friedmann-Lemaitre cosmologies can be analyzed in a variety of ways using Einstein's field equations, the Ricci and Bianchi identities, or the conservation equations for the stress-energy tensor, and possibly introducing a timelike reference congruence. The common ground is the use of gauge invariants derived from the metric tensor, the stress-energy tensor, or from vectors associated with a reference congruence, as basic variables. Although there is a complication in that there is no unique choice of gauge invariants, we will show that this can be used to advantage. With this in mind our first goal is to present an efficient way of constructing dimensionless gauge invariants associated with the tensors that are involved, and of determining their inter-relationships. Our second goal is to give a unified treatment of the various ways of writing the governing equations in dimensionless form using gauge-invariant variables, showing how simplicity can be achieved by a suitable choice of variables and normalization factors. Our third goal is to elucidate the connection between the metric-based approach and the so-called 1 + 3 gauge-invariant approach to cosmological perturbations. We restrict our considerations to linear perturbations, but our intent is to set the stage for the extension to second-order perturbations. (paper)
Mahootian, F.
2009-12-01
The rapid convergence of advancing sensor technology, computational power, and knowledge discovery techniques over the past decade has brought unprecedented volumes of astronomical data together with unprecedented capabilities of data assimilation and analysis. A key result is that a new, data-driven "observational-inductive'' framework for scientific inquiry is taking shape and proving viable. The anticipated rise in data flow and processing power will have profound effects, e.g., confirmations and disconfirmations of existing theoretical claims both for and against the big bang model. But beyond enabling new discoveries can new data-driven frameworks of scientific inquiry reshape the epistemic ideals of science? The history of physics offers a comparison. The Bohr-Einstein debate over the "completeness'' of quantum mechanics centered on a question of ideals: what counts as science? We briefly examine lessons from that episode and pose questions about their applicability to cosmology. If the history of 20th century physics is any indication, the abandonment of absolutes (e.g., space, time, simultaneity, continuity, determinacy) can produce fundamental changes in understanding. The classical ideal of science, operative in both physics and cosmology, descends from the European Enlightenment. This ideal has for over 200 years guided science to seek the ultimate order of nature, to pursue the absolute theory, the "theory of everything.'' But now that we have new models of scientific inquiry powered by new technologies and driven more by data than by theory, it is time, finally, to relinquish dreams of a "final'' theory.
Cosmology with decaying particles
International Nuclear Information System (INIS)
Turner, M.S.
1984-09-01
We consider a cosmological model in which an unstable massive relic particle species (denoted by X) has an initial mass density relative to baryons β -1 identically equal rho/sub X//rho/sub B/ >> 1, and then decays recently (redshift z less than or equal to 1000) into particles which are still relativistic today (denoted by R). We write down and solve the coupled equations for the cosmic scale factor a(t), the energy density in the various components (rho/sub X/, rho/sub R/, rho/sub B/), and the growth of linear density perturbations (delta rho/rho). The solutions form a one parameter (β) family of solutions; physically β -1 approx. = (Ω/sub R//Ω/sub NR/) x (1 + z/sub D/) = (ratio today of energy density of relativistic to nonrelativistic particles) x (1 + redshift of (decay)). We discuss the observational implications of such a cosmological model and compare our results to earlier results computed in the simultaneous decay approximation. In an appendix we briefly consider the case where one of the decay products of the X is massive and becomes nonrelativistic by the present epoch. 21 references
Cosmology with decaying particles
Energy Technology Data Exchange (ETDEWEB)
Turner, M.S.
1984-09-01
We consider a cosmological model in which an unstable massive relic particle species (denoted by X) has an initial mass density relative to baryons ..beta../sup -1/ identically equal rho/sub X//rho/sub B/ >> 1, and then decays recently (redshift z less than or equal to 1000) into particles which are still relativistic today (denoted by R). We write down and solve the coupled equations for the cosmic scale factor a(t), the energy density in the various components (rho/sub X/, rho/sub R/, rho/sub B/), and the growth of linear density perturbations (delta rho/rho). The solutions form a one parameter (..beta..) family of solutions; physically ..beta../sup -1/ approx. = (..cap omega../sub R//..cap omega../sub NR/) x (1 + z/sub D/) = (ratio today of energy density of relativistic to nonrelativistic particles) x (1 + redshift of (decay)). We discuss the observational implications of such a cosmological model and compare our results to earlier results computed in the simultaneous decay approximation. In an appendix we briefly consider the case where one of the decay products of the X is massive and becomes nonrelativistic by the present epoch. 21 references.
International Nuclear Information System (INIS)
Ginzburg, V.L.
1981-01-01
The problem of establishing boundaries between cosmology and philosophy is discussed. It is stated that the theoretic knowledge and observation data do not contradict the selection of one of non-stationary homogenous and isotropic relativistic models, which are also called the Friedmann models. In this model (with a zero Λ - member) there is a critical value of the substance density which is 10 -29 g/cm 2 . The determination of the average density of the Universe substance relatively to this value enables to choose between a closed and an open Universe model. Nowadays, this problem is not yet solved. But some philosophic theses reject the closed cosmological model without any naturally scientific argumentation. Critical remarks about such an approach to the problem studied are presented. The conclusion is made that the problems of the Universe volume infinity of finity, laws of its evolution in time or the like are not philosophic and should be considered taking into account the data of astronomic observations and modern physics
International Nuclear Information System (INIS)
Hartle, J.B.
1990-01-01
Our observations of the world give us specific facts. Here, there is a galaxy; there is none. Today, there is a supernova explosion; yesterday, there was a star. Here, there are fission fragments; before, there was a uranium nucleus. The task of physics is to compress the message which describes these facts into a shorter form -to compress it, in particular, to a form where the message consists of just a few observed facts together with simple universal laws of nature from which the rest can be deduced. In the past, physics has concentrated on finding dynamical laws which correlate facts at different times. Such laws predict later evolution given observed initial conditions. However, there is no logical reason why we could not look for laws which correlate facts at the same time. Such laws would be, in effect, laws of initial conditions. It was the limited nature of our observations which led to our focus on dynamical laws. Now, however, in cosmology, in the observations of the early universe and even on familiar scales, it is possible to discern regularities of the world which may find a compressed expression in a simple, testable, theory of the initial conditions of the universe as a whole. The search for this law of the initial conditions is the subject of quantum cosmology and the subject whose recent development is reviewed. (author)
Self-reliance and innovation of Qinshan phase II NPP project
International Nuclear Information System (INIS)
Ye Qizhen; Yang Lanhe
2007-01-01
This article mainly describes the self-reliance and innovation of Qinshan nuclear power project of phase II, in-between it contains new reactor core design, as well as related experimental and calculation analysis, especially for new reactor design produced fluid-induced vibration model test, theoretical analysis and testing in-built reactor; aiming at two-loop NSSS a series improvement made for safety systems and related safety analysis to enhance their reliability and redundancy; according to specialty of two-loop NSSS an optimization made for NPP parameters and design of related equipments, for the purpose to make the output of NPP maximal; design of main reactor building and T-G building also improved according to characteristics of two-loop NSSS and site conditions. CRDM and refueling machine are researched and manufactured on base of self-reliance, their performance are better than design requirements, large portion of key equipments are localized through different way. In construction first time realized the integrated erection of containment dome. During the commissioning non-nuclear steam driving of T-G set, as well as 500 kV high voltage rising using emergent diesel generator, etc. are carried out.In period of operation still continuous innovation and improvement are made, so that to keep the good record of operation. (authors)
International Nuclear Information System (INIS)
Queen, R.L.
1991-06-01
The Bureau of Reclamation (Reclamation) is proposing to modify or install additional transmission facilities between the Hoover Dam hydroelectric plant and the Western Area Power Authority substation near Boulder City, Nevada. Reclamation has completed cultural resource investigations to identify historic or prehistoric resources in the project area that might be affected during construction of the transmission line. Four possible transmission corridors approximately 50 feet wide and between 9.5 and 11.5 miles long were investigated. The proposed transmission lines either parallel or replace existing transmission lines. The corridors generally have undergone significant disturbance from past transmission line construction. A Class II sampling survey covering approximately 242 acres was conducted. Access or construction roads have not been identified and surveys of these areas will have to be completed in the future. No historic or prehistoric archeological sites were encountered within the four corridor right-of-ways. It is believed that the probability for prehistoric sites is very low. Four historic period sites were recorded that are outside, but near, the proposed corridor. These sites are not individually eligible for the National Register of Historic Places, but may be associated with the construction of Hoover Dam and contribute to a historic district or multiple property resource area focusing on the dam and its construction
Project management of the build of the shore test facility for the prototype of PWR II
International Nuclear Information System (INIS)
Clarkson, D.T.
1987-01-01
The PWR II is a new design of nuclear steam raising plant for the Royal Navy's submarines. It features improved engineering for safety, increased power, increased shock resistance, reduced noise transmission to sea and reduced manning requirement. It is to be tested in a new prototype testing facility, the Shore Test Facility, which is a section of submarine hull containing a prototype of the nuclear steam raising plant and its support system. It is installed at the Vulcan Naval Reactor Test establishment at Dounreay in Scotland. The function of the establishment is to test new designs of core and reactor plant, validate the mathematical models used in their design, develop improved methods of operation and maintenance of the plant and test new items of equipment. The Shore Test Facility was built in large sections at Barrow-in-Furness and transported to Scotland. The project management for the construction of the Shore Test Facility is explained. It involves personnel from the Royal Navy, and a large number of people working for the contractors involved in the buildings, transportation, operation and maintenance of the Facility. (U.K.)
AIDS incidence and mortality in injecting drug users: the AjUDE-Brasil II Project
Directory of Open Access Journals (Sweden)
Cardoso Mauro Nogueira
2006-01-01
Full Text Available This paper presents AIDS incidence and mortality among injecting drug users (IDUs reached by the AjUDE-Brasil II Project. From a cross-sectional survey, 478 IDUs were interviewed in three Brazilian cities: Porto Alegre, São José do Rio Preto, and Itajaí. The cohort was followed up in the Brazilian surveillance database for AIDS and mortality during 2000 and 2001. AIDS incidence was 1.1 cases per 100 person-years, and the mortality rate was 2.8 deaths per 100 person-years. AIDS cases only occurred in IDUs who reported ever having shared injecting equipment. Female gender (RR = 5.30, homelessness (RR = 6.16, and report of previous sexual relations with same-sex partners (RR = 6.21 were associated with AIDS. Deaths occurred only among males. Homelessness (RR = 3.00, lack of income (RR = 2.65, HIV seropositive status (RR = 4.52, and no history of incarceration (RR = 3.71 were also associated with death. These findings support evidence that gender and socioeconomic conditions are both determinants of morbidity and mortality in Brazilian IDUs.
Thermal-Mechanical Study of 3.9 GHz CW Coupler and Cavity for LCLS-II Project
Energy Technology Data Exchange (ETDEWEB)
Gonin, Ivan [Fermilab; Harms, Elvin [Fermilab; Khabiboulline, Timergali [Fermilab; Solyak, Nikolay [Fermilab; Yakovlev, Vyacheslav [Fermilab
2017-05-01
Third harmonic system was originally developed by Fermilab for FLASH facility at DESY and then was adopted and modified by INFN for the XFEL project [1-3]. In contrast to XFEL project, all cryomodules in LCLS-II project will operate in CW regime with higher RF average power for 1.3 GHz and 3.9 GHz cavities and couplers. Design of the cavity and fundamental power coupler has been modified to satisfy LCLS-II requirements. In this paper we discuss the results of COMSOL thermal and mechanical analysis of the 3.9 GHz coupler and cavity to verify proposed modifica-tion of the design. For the dressed cavity we present simulations of Lorentz force detuning, helium pressure sensitivity df/dP and major mechanical resonances.
Topics in Gravitation and Cosmology
Bahrami Taghanaki, Sina
This thesis is focused on two topics in which relativistic gravitational fields play an important role, namely early Universe cosmology and black hole physics. The theory of cosmic inflation has emerged as the most successful theory of the very early Universe with concrete and verifiable predictions for the properties of anisotropies of the cosmic microwave background radiation and large scale structure. Coalescences of black hole binaries have recently been detected by the Laser Interferometer Gravitational Wave Observatory (LIGO), opening a new arena for observationally testing the dynamics of gravity. In part I of this thesis we explore some modifications to the standard theory of inflation. The main predictions of single field slow-roll inflation have been largely consistent with cosmological observations. However, there remain some aspects of the theory that are not presently well understood. Among these are the somewhat interrelated issues of the choice of initial state for perturbations and the potential imprints of pre-inflationary dynamics. It is well known that a key prediction of the standard theory of inflation, namely the Gaussianity of perturbations, is a consequence of choosing a natural vacuum initial state. In chapter 3, we study the generation and detectability of non-Gaussianities in inflationary scalar perturbations that originate from more general choices of initial state. After that, in chapter 4, we study a simple but predictive model of pre-inflationary dynamics in an attempt to test the robustness of inflationary predictions. We find that significant deviations from the standard predictions are unlikely to result from models in which the inflaton field decouples from the pre-inflationary degrees of freedom prior to freeze-out of the observable modes. In part II we turn to a study of an aspect of the thermodynamics of black holes, a subject which has led to important advances in our understanding of quantum gravity. For objects which
Cosmological constraints with clustering-based redshifts
Kovetz, Ely D.; Raccanelli, Alvise; Rahman, Mubdi
2017-07-01
We demonstrate that observations lacking reliable redshift information, such as photometric and radio continuum surveys, can produce robust measurements of cosmological parameters when empowered by clustering-based redshift estimation. This method infers the redshift distribution based on the spatial clustering of sources, using cross-correlation with a reference data set with known redshifts. Applying this method to the existing Sloan Digital Sky Survey (SDSS) photometric galaxies, and projecting to future radio continuum surveys, we show that sources can be efficiently divided into several redshift bins, increasing their ability to constrain cosmological parameters. We forecast constraints on the dark-energy equation of state and on local non-Gaussianity parameters. We explore several pertinent issues, including the trade-off between including more sources and minimizing the overlap between bins, the shot-noise limitations on binning and the predicted performance of the method at high redshifts, and most importantly pay special attention to possible degeneracies with the galaxy bias. Remarkably, we find that once this technique is implemented, constraints on dynamical dark energy from the SDSS imaging catalogue can be competitive with, or better than, those from the spectroscopic BOSS survey and even future planned experiments. Further, constraints on primordial non-Gaussianity from future large-sky radio-continuum surveys can outperform those from the Planck cosmic microwave background experiment and rival those from future spectroscopic galaxy surveys. The application of this method thus holds tremendous promise for cosmology.
The cosmological perturbation theory in loop cosmology with holonomy corrections
International Nuclear Information System (INIS)
Wu, Jian-Pin; Ling, Yi
2010-01-01
In this paper we investigate the scalar mode of first-order metric perturbations over spatially flat FRW spacetime when the holonomy correction is taken into account in the semi-classical framework of loop quantum cosmology. By means of the Hamiltonian derivation, the cosmological perturbation equations is obtained in longitudinal gauge. It turns out that in the presence of metric perturbation the holonomy effects influence both background and perturbations, and contribute the non-trivial terms S h1 and S h2 in the cosmological perturbation equations
Energy Technology Data Exchange (ETDEWEB)
Barbour, J B [Department of Physics and Astronomy, University of Rochester (United States)
2007-02-07
These colloquium proceedings will be valuable, the blurb says, for graduate students and researchers in cosmology and theoretical astrophysics. Specifically, the book 'looks at both the strengths and weaknesses of the current big bang model in explaining certain puzzling data' and gives a 'comprehensive coverage of the expanding field of cosmology'. The reality is rather different. Conference proceedings rarely compare in value with a solid monograph or good review articles, and Current Issues in Cosmology is no exception. The colloquium was convened by the two editors, who have both long harboured doubts about the big bang, and was held in Paris in June 2004. The proceedings contain 19 presented papers and relatively brief summary comments by four panel speakers. The questions and answers at the end of each talk and a general discussion at the end were recorded and transcribed but contain little of interest. The nature of the colloquium is indicated by panellist Francesco Bertola's comment: 'While in the 1950s it was possible to speak of rival theories in cosmology, now the big-bang picture has no strong rivals. This is confirmed by the fact that out of 1500 members of the IAU Division VIII (Galaxies and the Universe) only a dozen, although bright people, devote their time to the heterodox views.' This was largely a platform for them to give their views. At least half of the dozen, all the 'usual suspects', were present: Geoffery and Margaret Burbidge, Jayant Narlikar, Halton Arp, Chandra Wickramasinghe and, in spirit only but playing a role somewhat like the ghost of Hamlet's father, the late Fred Hoyle. Doubters presented 12 of the 19 papers. Orthodoxy should certainly be challenged and the sociology of science questioned, but I found two main problems with this book. The papers putting the orthodox view are too short, even perfunctory. The most that a serious graduate student would get out of them is a reference
International Nuclear Information System (INIS)
Barbour, J B
2007-01-01
These colloquium proceedings will be valuable, the blurb says, for graduate students and researchers in cosmology and theoretical astrophysics. Specifically, the book 'looks at both the strengths and weaknesses of the current big bang model in explaining certain puzzling data' and gives a 'comprehensive coverage of the expanding field of cosmology'. The reality is rather different. Conference proceedings rarely compare in value with a solid monograph or good review articles, and Current Issues in Cosmology is no exception. The colloquium was convened by the two editors, who have both long harboured doubts about the big bang, and was held in Paris in June 2004. The proceedings contain 19 presented papers and relatively brief summary comments by four panel speakers. The questions and answers at the end of each talk and a general discussion at the end were recorded and transcribed but contain little of interest. The nature of the colloquium is indicated by panellist Francesco Bertola's comment: 'While in the 1950s it was possible to speak of rival theories in cosmology, now the big-bang picture has no strong rivals. This is confirmed by the fact that out of 1500 members of the IAU Division VIII (Galaxies and the Universe) only a dozen, although bright people, devote their time to the heterodox views.' This was largely a platform for them to give their views. At least half of the dozen, all the 'usual suspects', were present: Geoffery and Margaret Burbidge, Jayant Narlikar, Halton Arp, Chandra Wickramasinghe and, in spirit only but playing a role somewhat like the ghost of Hamlet's father, the late Fred Hoyle. Doubters presented 12 of the 19 papers. Orthodoxy should certainly be challenged and the sociology of science questioned, but I found two main problems with this book. The papers putting the orthodox view are too short, even perfunctory. The most that a serious graduate student would get out of them is a reference to a far better review article or book on modern
The cosmic microwave background data and their implications for cosmology
Tudose, V
2003-01-01
Recently the results from three projects (BOOMERANG, DASI and MAXIMA) dealing with the observation of the temperature and isotropies of the cosmic microwave background (CMB) were published. It was a real breakthrough for cosmology since these data established a new level in understanding the universe. Here we present a review of the main results obtained by the projects mentioned above, emphasizing their significance to the nowadays status of cosmology. In this respect we report on the increasing evidence for an inflationary period in the very early stages after the Big Bang, we discuss at large the values of the cosmological parameters and we acknowledge the picture of the universe as it appears from the CMB data. (authors)
International Nuclear Information System (INIS)
Nottale, Laurent
2003-01-01
The principle of relativity, when it is applied to scale transformations, leads to the suggestion of a generalization of fundamental dilations laws. These new special scale-relativistic resolution transformations involve log-Lorentz factors and lead to the occurrence of a minimal and of a maximal length-scale in nature, which are invariant under dilations. The minimal length-scale, that replaces the zero from the viewpoint of its physical properties, is identified with the Planck length l P , and the maximal scale, that replaces infinity, is identified with the cosmic scale L=Λ -1/2 , where Λ is the cosmological constant.The new interpretation of the Planck scale has several implications for the structure and history of the early Universe: we consider the questions of the origin, of the status of physical laws at very early times, of the horizon/causality problem and of fluctuations at recombination epoch.The new interpretation of the cosmic scale has consequences for our knowledge of the present universe, concerning in particular Mach's principle, the large number coincidence, the problem of the vacuum energy density, the nature and the value of the cosmological constant. The value (theoretically predicted ten years ago) of the scaled cosmological constant Ω Λ =0.75+/-0.15 is now supported by several different experiments (Hubble diagram of Supernovae, Boomerang measurements, gravitational lensing by clusters of galaxies).The scale-relativity framework also allows one to suggest a solution to the missing mass problem, and to make theoretical predictions of fundamental energy scales, thanks to the interpretation of new structures in scale space: fractal/classical transitions as Compton lengths, mass-coupling relations and critical value 4π 2 of inverse couplings. Among them, we find a structure at 3.27+/-0.26x10 20 eV, which agrees closely with the observed highest energy cosmic rays at 3.2+/-0.9x10 20 eV, and another at 5.3x10 -3 eV, which corresponds to the
International Nuclear Information System (INIS)
Sato, Toshinori; Sasamoto, Hiroshi; Ishii, Eiichi; Matsuoka, Toshiyuki; Hayano, Akira; Miyakawa, Kazuya; Fujita, Tomoo; Tanai, Kenji; Nakayama, Masashi; Takeda, Masaki; Yokota, Hideharu; Aoyagi, Kazuhei; Ohno, Hirokazu; Shigeta, Naotaka; Hanamuro, Takahiro; Ito, Hiroaki
2017-03-01
The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. The project consists of two major research areas, 'Geoscientific Research' and 'R and D on Geological Disposal', and proceeds in three overlapping phases, 'Phase I: Surface-based investigation', 'Phase II: Construction' and 'Phase III: Operation', over a period of 20 years. This report summarizes the results of the Phase II investigations carried out from April 2005 to June 2014 to a depth of 350 m. Integration of work from different disciplines into a 'geosynthesis' ensures that the Phase II goals have been successfully achieved and identifies key issues that need to be addressed in the Phase II investigations. Efforts are made to summarize as many lessons learnt from the Phase II investigations and other technical achievements as possible to form a 'knowledge base' that will reinforce the technical basis for both implementation and the formulation of safety regulations. (author)
Inflationary cosmologies from compactification?
International Nuclear Information System (INIS)
Wohlfarth, Mattias N.R.
2004-01-01
We consider the compactification of (d+n)-dimensional pure gravity and of superstring or M-theory on an n-dimensional internal space to a d-dimensional Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmology, with a spatial curvature k=0,±1, in the Einstein conformal frame. The internal space is taken to be a product of Einstein spaces, each of which is allowed to have arbitrary curvature and a time-dependent volume. By investigating the effective d-dimensional scalar potential, which is a sum of exponentials, it is shown that such compactifications, in the k=0,+1 cases, do not lead to large amounts of accelerating expansion of the scale factor of the resulting FLRW universe, and, in particular, do not lead to inflation. The case k=-1 admits solutions with eternal accelerating expansion for which the acceleration, however, tends to zero at late times
BMSSM implications for cosmology
International Nuclear Information System (INIS)
Bernal, Nicolas; Blum, Kfir; Nir, Yosef; Losada, Marta
2009-01-01
The addition of non-renormalizable terms involving the Higgs fields to the MSSM (BMSSM) ameliorates the little hierarchy problem of the MSSM. We analyze in detail the two main cosmological issues affected by the BMSSM: dark matter and baryogenesis. The regions for which the relic abundance of the LSP is consistent with WMAP and collider constraints are identified, showing that the bulk region and other previously excluded regions are now permitted. Requiring vacuum stability limits the allowed regions. Based on a two-loop finite temperature effective potential analysis, we show that the electroweak phase transition can be sufficiently first order in regions that for the MSSM are incompatible with the LEP Higgs mass bound, including parameter values of tan β∼ t -tilde 1 >m t , m Q < < TeV.
Cosmological disformal invariance
Energy Technology Data Exchange (ETDEWEB)
Domènech, Guillem; Sasaki, Misao [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Naruko, Atsushi, E-mail: guillem.domenech@yukawa.kyoto-u.ac.jp, E-mail: naruko@th.phys.titech.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)
2015-10-01
The invariance of physical observables under disformal transformations is considered. It is known that conformal transformations leave physical observables invariant. However, whether it is true for disformal transformations is still an open question. In this paper, it is shown that a pure disformal transformation without any conformal factor is equivalent to rescaling the time coordinate. Since this rescaling applies equally to all the physical quantities, physics must be invariant under a disformal transformation, that is, neither causal structure, propagation speed nor any other property of the fields are affected by a disformal transformation itself. This fact is presented at the action level for gravitational and matter fields and it is illustrated with some examples of observable quantities. We also find the physical invariance for cosmological perturbations at linear and high orders in perturbation, extending previous studies. Finally, a comparison with Horndeski and beyond Horndeski theories under a disformal transformation is made.
LHC, Astrophysics and Cosmology
Directory of Open Access Journals (Sweden)
Giulio Auriemma
2014-12-01
Full Text Available In this paper we discuss the impact on cosmology of recent results obtained by the LHC (Large Hadron Collider experiments in the 2011-2012 runs, respectively at √s = 7 and 8 TeV. The capital achievement of LHC in this period has been the discovery of a spin-0 particle with mass 126 GeV/c2, very similar to the Higgs boson of the Standard Model of Particle Physics. Less exciting, but not less important, negative results of searches for Supersymmetric particles or other exotica in direct production or rare decays are discussed in connection with particles and V.H.E. astronomy searches for Dark Matter.
International Nuclear Information System (INIS)
Tayler, R.J.
1983-01-01
The standard model of the hot big bang cosmological theory, which appears to be in agreement, at least qualitatively, with the observed properties of the Universe, assumes that the early Universe was homogeneous and isotropic and that it has been continuously expanding from a state characterized by very high temperature and density, where matter and radiation were to a good approximation in a state of thermodynamic equilibrium. In this standard model, it is assumed that baryon number, charge number and the various lepton numbers are all conserved. Only the baryon number is non-zero and this, expressed as the ratio of the net number of baryons (baryons minus antibaryons) to the number of photons per unit volume is the undefined parameter in the model. The author discusses the importance of knowing how many types of neutrinos there are with regard to the He 4 abundance, and the implication of a small, non-zero neutrino mass. (Auth.)
White, S
1994-01-01
Galaxy clusters are the largest coherent objects in Universe. It has been known since 1933 that their dynamical properties require either a modification of the theory of gravity, or the presence of a dominant component of unseen material of unknown nature. Clusters still provide the best laboratories for studying the amount and distribution of this dark matter relative to the material which can be observed directly -- the galaxies themselves and the hot,X-ray-emitting gas which lies between them.Imaging and spectroscopy of clusters by satellite-borne X -ray telescopes has greatly improved our knowledge of the structure and composition of this intergalactic medium. The results permit a number of new approaches to some fundamental cosmological questions,but current indications from the data are contradictory. The observed irregularity of real clusters seems to imply recent formation epochs which would require a universe with approximately the critical density. On the other hand, the large baryon fraction observ...
Directory of Open Access Journals (Sweden)
Indah Urwatin Wusqo
2016-12-01
Full Text Available Penelitian ini bertujuan untuk (1 Mengembangkan asesmen alternatif pada praktikum kimia dasar II melalui chemistry fair project berbasis konservasi dengan memanfaatkan daily chemical(2 Mengetahui tingkat kevalidan, kepraktisan dan keefektifannya. Penelitian ini merupakan penelitian pengembangan (Development Research Model pengembangan yang diterapkan Dick dan Carey (1985. Subjek uji coba terbatas maupun subjek uji coba lapangan adalah dosen dan mahasiswa Prodi Pendidikan IPA UNNES. Sampel ditentukan secara purposive, yaitu dosen pengampu dan mahasiswa yang menempuh mata kuliah Praktikum Kimia Dasar II. Data yang diperoleh dari uji coba ini adalah: (1 masukan dari pakar, untuk menentukan validitas isi dan konstruk dari fitur asesmen; (2 masukan dari sampel uji coba terbatas, untuk menentukan kepraktisan petunjuk chemistry fair project (CFP berbasis konservasi dengan memanfaatkan daily chemical ; Instrumen pengumpul data berupa angket keterbacaan petunjuk pembuatan chemistry fair project (CFP berbasis konservasi dengan memanfaatkan daily chemical, pedoman penskoran. (3 data hasil belajar siswa untuk mengetahui efektivitas asesmen. Masukan dari pakar angket mahasiswa, dan nilai chemistry fair project (CFP sampel ujicoba terbatas dianalisis secara kualitatif, dan kuantitatif. Asesmen alternative Praktikum Kimia Dasar II yang dikembangkan dikatakan berhasil baik apabila asesmen yang dikembangkan valid, praktis, dan efektif.
Decoherence in quantum cosmology
International Nuclear Information System (INIS)
Halliwell, J.J.
1989-01-01
We discuss the manner in which the gravitational field becomes classical in quantum cosmology. This involves two steps. First, one must show that the quantum state of the gravitational field becomes strongly peaked about a set of classical configurations. Second, one must show that the system is in one of a number of states of a relatively permanent nature that have negligible interference with each other. This second step involves decoherence---destruction of the off-diagonal terms in the density matrix, representing interference. To introduce the notion of decoherence, we discuss it in the context of the quantum theory of measurement, following the environment-induced superselection approach of Zurek. We then go on to discuss the application of these ideas to quantum cosmology. We show, in a simple homogeneous isotropic model, that the density matrix of the Universe will decohere if the long-wavelength modes of an inhomogeneous massless scalar field are traced out. These modes effectively act as an environment which continuously ''monitors'' the scale factor. The coherence width is very small except in the neighborhood of a classical bounce. This means that one cannot really say that a classical solution bounces because the notion of classical spacetime does not apply. The coherence width decreases as the scale factor increases, which has implications for the arrow of time. We also show, using decoherence arguments, that the WKB component of the wave function of the Universe which represents expanding universes has negligible interference with the collapsing component. This justifies the usual assumption that they may be treated separately
Cosmological and supernova neutrinos
Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Shibagaki, S.; Suzuki, T.
2014-06-01
The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial 7Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and 7Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like 7Li, 11B, 92Nb, 138La and 180Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ13 with predicted and observed supernova-produced abundance ratio 11B/7Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.
Cosmological and supernova neutrinos
Energy Technology Data Exchange (ETDEWEB)
Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Balantekin, A. B. [Department of Physics, University of Wisconsin - Madison, Wisconsin 53706 (United States); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Mathews, G. J. [Department of Physics, University of Notre Dame, IN 46556 (United States); Nakamura, K. [Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Pehlivan, Y. [Mimar Sinan GSÜ, Department of Physics, Şişli, İstanbul 34380 (Turkey); Suzuki, T. [Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)
2014-06-24
The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.
World War II, The CANOL project and the Marwell Tar Pit: a case study
International Nuclear Information System (INIS)
Dobrowolsky, H.
2000-01-01
The CANOL project was a joint U.S.-Canada undertaking during World War II. It entailed the construction of a road and pipeline from the oil fields of Norman Wells on the Mackenzie River, 960 kms over the Mackenzie Mountains to a new refinery at Whitehorse. The goal was to provide a secure supply of aviation fuel far from the menace of Japanese bombers. Initially, the pipeline was expected to operate by October 1942. In actual fact, the first gasoline was not produced in the crude distillation unit until April 24, 1944, and it was not until November 1944 that the refinery finally began producing aviation fuel. Four months later, the pipeline and the refinery were shut down. The project cost American taxpayers $ 134 million. A total of 2650 kms of pipeline was laid. During the first nine months of pipeline operation 46,000 barrels of oil was spilled, much of it directly into the Mackenzie River. Total production from the refinery, which itself cost $ 27 million, wa 866,670 barrels of products. When the refinery was shut down, most of the refinery structures were dismantled and moved, via the Alaska Highway, to the newly discovered Leduc oilfields, but buildings, tanks and hydrocarbon waste were left behind. In a 1960 report it was estimated that some four million litres of oil has been pumped into a pit located within the containment berm formerly surrounding an 80,000 barrel oil storage tank which was dismantled after the shutdown. The bureaucratic dispute about who is responsible for cleaning up has been an issue ever since. The cost of cleanup was estimated at about $ 4 million in 1994. Since the federal government, the original owners of the land , transferred the land to provincial jurisdiction in 1970, it disclaimed any responsibility for site cleanup, however, there has been some recent evidence of willingness on the part of the Department of National Defence and the Department of Indian and Northern Affairs to determine proper actions to clean up the site
Combining experimental and cosmological constraints on heavy neutrinos
Directory of Open Access Journals (Sweden)
Marco Drewes
2017-08-01
Full Text Available We study experimental and cosmological constraints on the extension of the Standard Model by three right handed neutrinos with masses between those of the pion and W boson. We combine for the first time direct, indirect and cosmological constraints in this mass range. This includes experimental constraints from neutrino oscillation data, neutrinoless double β decay, electroweak precision data, lepton universality, searches for rare lepton decays, tests of CKM unitarity and past direct searches at colliders or fixed target experiments. On the cosmological side, big bang nucleosynthesis has the most pronounced impact. Our results can be used to evaluate the discovery potential of searches for heavy neutrinos at LHCb, BELLE II, SHiP, ATLAS, CMS or a future lepton collider.
Dark energy cosmology with generalized linear equation of state
International Nuclear Information System (INIS)
Babichev, E; Dokuchaev, V; Eroshenko, Yu
2005-01-01
Dark energy with the usually used equation of state p = wρ, where w const 0 ), where the constants α and ρ 0 are free parameters. This non-homogeneous linear equation of state provides the description of both hydrodynamically stable (α > 0) and unstable (α < 0) fluids. In particular, the considered cosmological model describes the hydrodynamically stable dark (and phantom) energy. The possible types of cosmological scenarios in this model are determined and classified in terms of attractors and unstable points by using phase trajectories analysis. For the dark energy case, some distinctive types of cosmological scenarios are possible: (i) the universe with the de Sitter attractor at late times, (ii) the bouncing universe, (iii) the universe with the big rip and with the anti-big rip. In the framework of a linear equation of state the universe filled with a phantom energy, w < -1, may have either the de Sitter attractor or the big rip
Cosmology and the weak interaction
Energy Technology Data Exchange (ETDEWEB)
Schramm, D.N. (Fermi National Accelerator Lab., Batavia, IL (USA)):(Chicago Univ., IL (USA))
1989-12-01
The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N{sub {nu}} {approximately} 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs.
Cosmology and the weak interaction
International Nuclear Information System (INIS)
Schramm, D.N.
1989-12-01
The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N ν ∼ 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs
International Nuclear Information System (INIS)
Makkar, H.P.S.
2002-01-01
The Joint FAO/IAEA programme has supported animal production research in Africa for many years through country Technical Co-operation (TC) Projects, Regional Projects (AFRA) and Co-ordinated Research Project (CRP). These activities have helped to build up the infrastructure needed in the countries concerned to conduct much of the research in animal reproduction and nutrition. In the past the Agency has provided technical assistance in defining reproductive indices of ruminant livestock species and identifying nutritional constraints to productivity of animals maintained on smallholder farms under various topographical and environmental conditions. In view of the satisfactory progress of AFRA Project VIII in identifying the major constraints to livestock productivity in the region, and the recognition of many Member States of the importance of supplementary feeding for improving milk and meat production, a regional strategy was proposed for developing affordable and sustainable supplementation packages for improving productivity from smallholder farms using locally available feed resources. The new Regional Project was initiated in 1997 with the following objectives: 1. To produce a supplementary feed in the form of a convenient and easy-to-use package for improving milk and meat production in peri-urban areas 2. To promote the uptake of this technology through demonstrations of its advantages in terms of increased productivity and benefit: cost ratio 3. To maximize the use of locally available feed material such as molasses, cereal bran, legume tree leaves, oil seed meals, etc. for feeding ruminant livestock, thereby reducing the use of high cost concentrate feeds 4. To promote technical co-operation amongst developing countries (TCDC) in the region and take advantage of established infrastructure and available human and technical resources to solve problems of common interest. From 1997 until 2000 the project has been operational with 13 Member States
A new cosmological paradigm: the cosmological constant and dark matter
International Nuclear Information System (INIS)
Krauss, L.M.
1998-01-01
The Standard Cosmological Model of the 1980 close-quote s is no more. I describe the definitive evidence that the density of matter is insufficient to result in a flat universe, as well as the mounting evidence that the cosmological constant is not zero. I finally discuss the implications of these results for particle physics and direct searches for non-baryonic dark matter. copyright 1998 American Institute of Physics
The cosmological term and a modified Brans-Dicke cosmology
International Nuclear Information System (INIS)
Endo, M.; Fukui, T.
1977-01-01
Adding the cosmological term Λ, which is assumed to be variable in this paper, to the Brans-Dicke Lagrangian, an attempt is made to understand the meaning of the term and to relate it to the mass of the universe. The Dirac large-number hypothesis is considered, applying the results obtained from the application of the present theory to a uniform cosmological model. (author)
Cosmological applications in Kaluza—Klein theory
International Nuclear Information System (INIS)
Wanas, M.I.; Nashed, Gamal G. L.; Nowaya, A.A.
2012-01-01
The field equations of Kaluza—Klein (KK) theory have been applied in the domain of cosmology. These equations are solved for a flat universe by taking the gravitational and the cosmological constants as a function of time t. We use Taylor's expansion of cosmological function, Λ(t), up to the first order of the time t. The cosmological parameters are calculated and some cosmological problems are discussed. (geophysics, astronomy, and astrophysics)
Heavy ion collisions and cosmology
Energy Technology Data Exchange (ETDEWEB)
Floerchinger, Stefan
2016-12-15
There are interesting parallels between the physics of heavy ion collisions and cosmology. Both systems are out-of-equilibrium and relativistic fluid dynamics plays an important role for their theoretical description. From a comparison one can draw interesting conclusions for both sides. For heavy ion physics it could be rewarding to attempt a theoretical description of fluid perturbations similar to cosmological perturbation theory. In the context of late time cosmology, it could be interesting to study dissipative properties such as shear and bulk viscosity and corresponding relaxation times in more detail. Knowledge and experience from heavy ion physics could help to constrain the microscopic properties of dark matter from observational knowledge of the cosmological fluid properties.
Thermodynamics in Loop Quantum Cosmology
International Nuclear Information System (INIS)
Li, L.F.; Zhu, J.Y.
2009-01-01
Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. Moreover, the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but also are actually found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid.
Modernism and cosmology absurd lights
Ebury, Katherine
2014-01-01
Through examining the work of W. B. Yeats, James Joyce, and Samuel Beckett, Katherine Ebury shows cosmology had a considerable impact on modernist creative strategies, developing alternative reading models of difficult texts such as Finnegans Wake and 'The Trilogy'.
Newtonian cosmology Newton would understand
International Nuclear Information System (INIS)
Lemons, D.S.
1988-01-01
Isaac Newton envisioned a static, infinite, and initially uniform, zero field universe that was gravitationally unstable to local condensations of matter. By postulating the existence of such a universe and using it as a boundary condition on Newtonian gravity, a new field equation for gravity is derived, which differs from the classical one by a time-dependent cosmological term proportional to the average mass density of the universe. The new field equation not only makes Jeans' analysis of the gravitational instability of a Newtonian universe consistent, but also gives rise to a family of Newtonian evolutionary cosmologies parametrized by a time-invariant expansion velocity. This Newtonian cosmology contrasts with both 19th-century ones and with post general relativity Newtonian cosmology
Introduction. Cosmology meets condensed matter.
Kibble, T W B; Pickett, G R
2008-08-28
At first sight, low-temperature condensed-matter physics and early Universe cosmology seem worlds apart. Yet, in the last few years a remarkable synergy has developed between the two. It has emerged that, in terms of their mathematical description, there are surprisingly close parallels between them. This interplay has been the subject of a very successful European Science Foundation (ESF) programme entitled COSLAB ('Cosmology in the Laboratory') that ran from 2001 to 2006, itself built on an earlier ESF network called TOPDEF ('Topological Defects: Non-equilibrium Field Theory in Particle Physics, Condensed Matter and Cosmology'). The articles presented in this issue of Philosophical Transactions A are based on talks given at the Royal Society Discussion Meeting 'Cosmology meets condensed matter', held on 28 and 29 January 2008. Many of the speakers had participated earlier in the COSLAB programme, but the strength of the field is illustrated by the presence also of quite a few new participants.
Cosmology and unified gauge theory
Oraifeartaigh, L.
1981-09-01
Theoretical points in common between cosmology and unified gauge theory (UGT) are reviewed, with attention given to areas of one which have proven useful for the other. The underlying principles for both theoretical frameworks are described, noting the differences in scale, i.e., 10 to the 25th cm in cosmology and 10 to the -15th cm for UGT. Cosmology has produced bounds on the number of existing neutrino species, and also on the mass of neutrinos, two factors of interest in particle physics. Electrons, protons, and neutrinos, having been spawned from the same massive leptons, each composed of three quarks, have been predicted to be present in equal numbers in the Universe by UGT, in line with necessities of cosmology. The Grand UGT also suggests specific time scales for proton decay, thus accounting for the observed baryon assymmetry.
Evolution in bouncing quantum cosmology
International Nuclear Information System (INIS)
Mielczarek, Jakub; Piechocki, Włodzimierz
2012-01-01
We present the method of describing an evolution in quantum cosmology in the framework of the reduced phase space quantization of loop cosmology. We apply our method to the flat Friedmann-Robertson-Walker model coupled to a massless scalar field. We identify the physical quantum Hamiltonian that is positive-definite and generates globally a unitary evolution of the considered quantum system. We examine the properties of expectation values of physical observables in the process of the quantum big bounce transition. The dispersion of evolved observables is studied for the Gaussian state. Calculated relative fluctuations enable an examination of the semi-classicality conditions and possible occurrence of the cosmic forgetfulness. Preliminary estimations based on the cosmological data suggest that there was no cosmic amnesia. Presented results are analytical, and numerical computations are only used for the visualization purposes. Our method may be generalized to sophisticated cosmological models including the Bianchi-type universes. (paper)
Precision cosmology and the landscape
International Nuclear Information System (INIS)
Bousso, Raphael; Bousso, Raphael
2006-01-01
After reviewing the cosmological constant problem--why is Lambda not huge?--I outline the two basic approaches that had emerged by the late 1980s, and note that each made a clear prediction. Precision cosmological experiments now indicate that the cosmological constant is nonzero. This result strongly favors the environmental approach, in which vacuum energy can vary discretely among widely separated regions in the universe. The need to explain this variation from first principles constitutes an observational constraint on fundamental theory. I review arguments that string theory satisfies this constraint, as it contains a dense discretuum of metastable vacua. The enormous landscape of vacua calls for novel, statistical methods of deriving predictions, and it prompts us to reexamine our description of spacetime on the largest scales. I discuss the effects of cosmological dynamics, and I speculate that weighting vacua by their entropy production may allow for prior-free predictions that do not resort to explicitly anthropic arguments
Chaos, decoherence and quantum cosmology
International Nuclear Information System (INIS)
Calzetta, Esteban
2012-01-01
In this topical review we discuss the connections between chaos, decoherence and quantum cosmology. We understand chaos as classical chaos in systems with a finite number of degrees of freedom, decoherence as environment induced decoherence and quantum cosmology as the theory of the Wheeler-DeWitt equation or else the consistent history formulation thereof, first in mini super spaces and later through its extension to midi super spaces. The overall conclusion is that consideration of decoherence is necessary (and probably sufficient) to sustain an interpretation of quantum cosmology based on the wavefunction of the Universe adopting a Wentzel-Kramers-Brillouin form for large Universes, but a definitive account of the semiclassical transition in classically chaotic cosmological models is not available in the literature yet. (topical review)
Physical and Relativistic Numerical Cosmology.
Anninos, Peter
1998-01-01
In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of baryonic matter, electromagnetic fields, and spacetime curvature, for example. Although it is difficult to incorporate all these physical elements into a single complete model of our Universe, advances in computing methods and technologies have contributed significantly towards our understanding of cosmological models, the Universe, and astrophysical processes within them. A sample of numerical calculations addressing specific issues in cosmology are reviewed in this article: from the Big Bang singularity dynamics to the fundamental interactions of gravitational waves; from the quark-hadron phase transition to the large scale structure of the Universe. The emphasis, although not exclusively, is on those calculations designed to test different models of cosmology against the observed Universe.
Physical and Relativistic Numerical Cosmology
Directory of Open Access Journals (Sweden)
Peter Anninos
1998-01-01
Full Text Available In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of baryonic matter, electromagnetic fields, and spacetime curvature, for example. Although it is difficult to incorporate all these physical elements into a single complete model of our Universe, advances in computing methods and technologies have contributed significantly towards our understanding of cosmological models, the Universe, and astrophysical processes within them. A sample of numerical calculations addressing specific issues in cosmology are reviewed in this article: from the Big Bang singularity dynamics to the fundamental interactions of gravitational waves; from the quark--hadron phase transition to the large scale structure of the Universe. The emphasis, although not exclusively, is on those calculations designed to test different models of cosmology against the observed Universe.
Three Studies in Epicurean Cosmology
Bakker, F.A.
2010-01-01
This dissertation consists of three studies dealing with various aspects of Epicurean cosmology. The first study discusses the Epicurean practice of explaining astronomical and meteorological phenomena by multiple alternative theories. The second study compares the meteorological accounts of
Bimetric gravity is cosmologically viable
Directory of Open Access Journals (Sweden)
Yashar Akrami
2015-09-01
Full Text Available Bimetric theory describes gravitational interactions in the presence of an extra spin-2 field. Previous work has suggested that its cosmological solutions are generically plagued by instabilities. We show that by taking the Planck mass for the second metric, Mf, to be small, these instabilities can be pushed back to unobservably early times. In this limit, the theory approaches general relativity with an effective cosmological constant which is, remarkably, determined by the spin-2 interaction scale. This provides a late-time expansion history which is extremely close to ΛCDM, but with a technically-natural value for the cosmological constant. We find Mf should be no larger than the electroweak scale in order for cosmological perturbations to be stable by big-bang nucleosynthesis. We further show that in this limit the helicity-0 mode is no longer strongly-coupled at low energy scales.
Clues to the 'Magellanic Galaxy' from cosmological simulations
Sales, Laura V.; Navarro, Julio F.; Cooper, Andrew P.; White, Simon D. M.; Frenk, Carlos S.; Helmi, Amina
2011-01-01
We use cosmological simulations from the Aquarius Project to study the orbital history of the Large Magellanic Cloud (LMC) and its potential association with other satellites of the Milky Way (MW). We search for dynamical analogues to the LMC and find a subhalo that matches the LMC position and
Horizon-preserving dualities and perturbations in non-canonical scalar field cosmologies
International Nuclear Information System (INIS)
Geshnizjani, Ghazal; Kinney, William H.; Dizgah, Azadeh Moradinezhad
2012-01-01
We generalize the cosmological duality between inflation and cyclic contraction under the interchange a↔H to the case of non-canonical scalar field theories with varying speed of sound. The single duality in the canonical case generalizes to a family of three dualities constructed to leave the cosmological acoustic horizon invariant. We find three classes of models: (I) DBI inflation, (II) the non-canonical generalization of cyclic contraction, and (III) a new cosmological solution with rapidly decreasing speed of sound and relatively slowly growing scale factor, which we dub stalled cosmology. We construct dual analogs to the inflationary slow roll approximation, and solve for the curvature perturbation in all three cases. Both cyclic contraction and stalled cosmology predict a strongly blue spectrum for the curvature perturbations inconsistent with observations
HAWKING'S Theory of Quantum Cosmology
Zhi, Fang Li; Chao, Wu Zhong
The most important problem in cosmology is the birth of the universe. Recently Hartle and Hawking put forward a ground state proposal for the quantum state of the universe which incorporates the idea that the universe must come from nothing. Many models have been discussed in quantum cosmology with this boundary condition. It has been shown that every model is a step towards to a realistic universe, i.e. a 4-dimensional isotropic universe with a long inflationary stage.
Quantum cosmology on the worldsheet
International Nuclear Information System (INIS)
Cooper, A.R.; Susskind, L.; Thorlacius, L.
1991-08-01
Two-dimensional quantum gravity coupled to conformally invariant matter central c > 25 provides a toy model for quantum gravity in four dimensions. Two-dimensional quantum cosmology can thus be studied in terms of string theory in background fields. The large scale cosmological constant depends on non-linear dynamics in the string theory target space and does not appear to be suppressed by wormhole effects. 13 refs
Cosmology and the Sinusoidal Potential
Bartlett, David F.
2006-06-01
The nature of dark matter (and dark energy) remains a mystery. An alternative is being explored by several scientists: changing Newton's (and Einstein's) field equations. The sinusoidal potential is the latest attempt[1]. Here the gravitational law is alternately attractive and repulsive:φ = -GM cos(kor)/r, where λo=2π/ko = 1/20 of the distance from the sun to the center of the Milky Way. The proposal accommodates several structural features of the Milky Way including, paradoxically, its spiral shape and flat rotation curve. The sinusoidal potential's unique feature is strong galactic tidal forces (dg/dr). These may explain why the new planetoid Sedna is securely between the Kuiper Belt and the Oort cloud and why distant comets are more influenced by galactic tides that are in the r, rather than the z-direction.At this meeting I discuss the consequences of the sinusoidal potential for cosmology. Here the alternation of attraction and repulsion gives (i) an open universe, and (ii) gravitational lensing which is usually weak, but occasionally very strong. An open universe is one that, asymptotically, has a size R which varies directly as time t. The open universe conflicts both with the old Einstein-deSitter model (R α t2/3} and the new accelerating one. The evidence for an accelerating universe decisively rejects the Einstein-deSitter model. The rejection of an open (or empty) universe is less secure. This rejection is influenced by the different ways the groups studying the brightness of supernovae use the HST. Surprising additional inputs include neutrino masses, the equivalence principle, LSB galaxies, and "over-luminous" Sn1a. I thank Mostafa Jon Dadras and Patrick Motl for early help and John Cumalat for continual support. [1] D.F. Bartlett, "Analogies between electricity and gravity", Metrologia 41, S115-S124 (2004).
Roberts, Alex
2016-08-01
Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding global properties of the universe and outcomes of particular experiments, according to a single probability formula. This provides complete unification of the eternally inflating multiverse and many worlds in quantum mechanics. We elucidate how cosmological parameters can be calculated in this framework, and study the probability distribution for the value of the cosmological constant. We consider both positive and negative values, and find that the observed value is consistent with the calculated distribution at an order of magnitude level. In particular, in contrast to the case of earlier measure proposals, our framework prefers a positive cosmological constant over a negative one. These results depend only moderately on how we model galaxy formation and life evolution therein. We explore supersymmetric theories in which the Higgs mass is boosted by the non-decoupling D-terms of an extended U(1) X gauge symmetry, defined here to be a general linear combination of hypercharge, baryon number, and lepton number. Crucially, the gauge coupling, gX, is bounded from below to accommodate the Higgs mass, while the quarks and leptons are required by gauge invariance to carry non-zero charge under U(1)X. This induces an irreducible rate, sigmaBR, for pp → X → ll relevant to existing and future resonance searches, and gives rise to higher dimension operators that are stringently constrained by precision electroweak measurements. Combined, these bounds define a maximally allowed region in the space of observables, (sigmaBR, mX), outside of which is excluded by naturalness and experimental limits. If natural supersymmetry utilizes non-decoupling D-terms, then the associated X boson can only be observed within this window, providing a model independent 'litmus test' for this broad
Was Newtonian cosmology really inconsistent?
Vickers, Peter
This paper follows up a debate as to the consistency of Newtonian cosmology. Whereas Malament [(1995). Is Newtonian cosmology really inconsistent? Philosophy of Science 62, 489-510] has shown that Newtonian cosmology is not inconsistent, to date there has been no analysis of Norton's claim [(1995). The force of Newtonian cosmology: Acceleration is relative. Philosophy of Science 62, 511-522.] that Newtonian cosmology was inconsistent prior to certain advances in the 1930s, and in particular prior to Seeliger's seminal paper of Seeliger [(1895). Über das Newton'sche Gravitationsgesetz. Astronomische Nachrichten 137 (3273), 129-136.] In this paper I agree that there are assumptions, Newtonian and cosmological in character, and relevant to the real history of science, which are inconsistent. But there are some important corrections to make to Norton's account. Here I display for the first time the inconsistencies-four in total-in all their detail. Although this extra detail shows there to be several different inconsistencies, it also goes some way towards explaining why they went unnoticed for 200 years.
Quantum cosmology and baby universes
International Nuclear Information System (INIS)
Grishchuk, L.P.
1990-01-01
The contributed papers presented to the workshop on ''Quantum Cosmology and Baby Universes'' have demonstrated the great interest in, and rapid development of, the field of quantum cosmology. In my view, there are at least three areas of active research at present. The first area can be defined as that of practical calculations. Here researchers are dealing with the basic quantum cosmological equation, which is the Wheeler-DeWitt equation. They try to classify all possible solutions to the Wheeler-DeWitt equation or seek a specific integration contour in order to select one particular wave function or generalize the simple minisuperspace models to more complicated cases, including various inhomogeneities, anisotropies, etc. The second area of research deals with the interpretational issues of quantum cosmology. There are still many questions about how to extract the observational consequences from a given cosmological wave function, the role of time in quantum cosmology, and how to reformulate the rules of quantum mechanics in such a way that they could be applicable to the single system which is our Universe. The third area of research is concerned with the so-called ''third quantization'' of gravity. In this approach a wave function satisfying the Wheeler-DeWitt equation becomes an operator acting on a Wave Function of the many-universes system. Within this approach one operates with Euclidean worm-holes joining different Lorentzian universes. (author)
Parameterized post-Newtonian cosmology
International Nuclear Information System (INIS)
Sanghai, Viraj A A; Clifton, Timothy
2017-01-01
Einstein’s theory of gravity has been extensively tested on solar system scales, and for isolated astrophysical systems, using the perturbative framework known as the parameterized post-Newtonian (PPN) formalism. This framework is designed for use in the weak-field and slow-motion limit of gravity, and can be used to constrain a large class of metric theories of gravity with data collected from the aforementioned systems. Given the potential of future surveys to probe cosmological scales to high precision, it is a topic of much contemporary interest to construct a similar framework to link Einstein’s theory of gravity and its alternatives to observations on cosmological scales. Our approach to this problem is to adapt and extend the existing PPN formalism for use in cosmology. We derive a set of equations that use the same parameters to consistently model both weak fields and cosmology. This allows us to parameterize a large class of modified theories of gravity and dark energy models on cosmological scales, using just four functions of time. These four functions can be directly linked to the background expansion of the universe, first-order cosmological perturbations, and the weak-field limit of the theory. They also reduce to the standard PPN parameters on solar system scales. We illustrate how dark energy models and scalar-tensor and vector-tensor theories of gravity fit into this framework, which we refer to as ‘parameterized post-Newtonian cosmology’ (PPNC). (paper)
Cosmology of a charged universe
International Nuclear Information System (INIS)
Barnes, A.
1979-01-01
The Proca generalization of electrodynamics admits the possibility that the universe could possess a net electric charge uniformly distributed throughout space, while possessing no electric field. A charged intergalactic (and intragalactic) medium of this kind could contain enough energy to be of cosmological importance. A general-relativistic model of cosmological expansion dominated by such a charged background has been calculated, and is consistent with present observational limits on the Hubble constant, the decleration parameter, and the age of the universe. However, if this cosmology applied at the present epoch, the very early expansion of the universe would have been much more rapid than in conventional ''big bang'' cosmologies, too rapid for cosmological nucleosynthesis or thermalization of the background radiation to have occurred. Hence, domination of the present expansion by background charge appears to be incompatible with the 3 K background and big-bang production of light elements. If the present background charge density were sufficiently small (but not strictly zero), expansion from the epoch of nucleosynthesis would proceed according to the conventional scenario, but the energy due to the background charge would have dominated at some earlier epoch. This last possibility leads to equality of pressure and energy density in the primordial universe, a condition of special significance in certain cosmological theories
Parameterized post-Newtonian cosmology
Sanghai, Viraj A. A.; Clifton, Timothy
2017-03-01
Einstein’s theory of gravity has been extensively tested on solar system scales, and for isolated astrophysical systems, using the perturbative framework known as the parameterized post-Newtonian (PPN) formalism. This framework is designed for use in the weak-field and slow-motion limit of gravity, and can be used to constrain a large class of metric theories of gravity with data collected from the aforementioned systems. Given the potential of future surveys to probe cosmological scales to high precision, it is a topic of much contemporary interest to construct a similar framework to link Einstein’s theory of gravity and its alternatives to observations on cosmological scales. Our approach to this problem is to adapt and extend the existing PPN formalism for use in cosmology. We derive a set of equations that use the same parameters to consistently model both weak fields and cosmology. This allows us to parameterize a large class of modified theories of gravity and dark energy models on cosmological scales, using just four functions of time. These four functions can be directly linked to the background expansion of the universe, first-order cosmological perturbations, and the weak-field limit of the theory. They also reduce to the standard PPN parameters on solar system scales. We illustrate how dark energy models and scalar-tensor and vector-tensor theories of gravity fit into this framework, which we refer to as ‘parameterized post-Newtonian cosmology’ (PPNC).
Effect of participation in the Fadama–II project on Participants' socio ...
African Journals Online (AJOL)
For most respondents, the socioeconomic status changed positively following participation in the project. Majority of the respondents in the study area participated actively in fadama meetings and other activities involved in project. Benefits derived from taking part in the project were generally high for most respondents (95.5 ...
Energy Technology Data Exchange (ETDEWEB)
Noll, B.; Rachner, M.; Frank, P.; Schmitz, G.; Geigle, K.P.; Meier, W.; Schuetz, H.; Aigner, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany). Inst. fuer Verbrennungstechnik; Kessler, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Goettingen (Germany). Inst. fuer Aerodynamik und Stroemungstechnik; Lehmann, B. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany). Inst. fuer Antriebstechnik; Forkert, T. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany). Simulation und Softwaretechnik
2002-07-01
In the year 1996 the spheres of competence of several DLR-Institutes working in the areas of fluid dynamics, reaction kinetics, combustion, numerical methods and laser measuring techniques have been brought together while contributing to the internal DLR project 'combustion chamber modelling (BKM)', in order to proceed with the computational simulation of combustion processes in combustion chambers of gas turbines. The main issue was the development of a research code for numerical simulation of fluid flow in real combustion chambers. Here the development of computational models of physical and chemical processes was emphasized, among other processes the formation of soot was treated. Moreover, a worldwide outstanding database of measured data for the purpose of code validation has been created within the framework of the BKM project using the laboratory facilities of the DLR, which are in Germany unique for the experimental investigation of the various processes in combustion chambers of gas turbines. The project BKM is part of the specific DLR-programme 'energy'. With the successful completion of the first phase of the project in 1998, a second project phase of three years (BKM II) has been launched at the beginning of 1999. Here the work of the first phase continued and new topics were tackled. The second phase of the project was partly founded by the DLR-programme 'aeronautics'. (orig.) [German] Im Jahr 1996 wurden die Faehigkeiten mehrerer DLR-Institute auf den Gebieten Stroemungsmechanik, Reaktionskinetik, Verbrennung sowie Numerische Verfahren und Laser-Messverfahren in dem DLR-internen Projekt 'Brennkammermodellierung' (BKM) zusammengefuehrt, um die rechnerische Simulation der Verbrennungsvorgaenge in Gasturbinen-Brennkammern voranzutreiben. Dabei war die Entwicklung eines Forschungscodes zur numerischen Simulation von realen Brennkammerstroemungen das vorrangige Ziel der Arbeiten. Ein besonderes Schwergewicht lag
Directory of Open Access Journals (Sweden)
Eduardo López López
2007-01-01
Full Text Available This is a review study which analyzes research that evaluates the long term effects of an early education program, the Abecedarian Project. The Abecedarian Project (ABC is a preventive compensatory education program for children from 0 to 5 years of high risk mothers. The experimental group (E received an intensive preschool treatment, while the control (C group did not. At five years old, each group was divided into another two groups: Two of these new groups (EE and CE received intensive schooling until the children reached 8 years old, while the other groups (EC and CC received no special treatment. The total sample was measured until each child reached 21 years. The results were as follows: The young adults, treated in the preschool years, had on average significantly higher cognitive test scores, earned higher scores on reading and math tests; they completed more years of education, they were more likely to attend a 4-year college or university, and they were less likely to become teen parents. Furthermore, the mothers of these students were more likely to reach a higher level of instruction and employment. Finally, the article discusses the validity of the study and the factors associated to the benefits (the early beginning, intensity and continuity of the program. Este es un estudio de revisión en el que se analizan las investigaciones que evalúan los efectos a lo largo del tiempo del temprano Abecedarian Project (ABC. El ABC es un programa compensador preventivo de 0-5 años y entresacados de madres de alto riesgo. El grupo experimental (E recibe tratamiento preescolar intensivo, no el control (C. Se prolongó escolarmente hasta los 8 años, subdividiéndose ambos grupos: Dos -EE y CE- recibieron tratamiento intensivo; otros (EC y CC convencional. Fueron medidos hasta los 21. Resultados: Los jóvenes adultos, tratados preescolarmente, mejoraron en rendimiento mental, lector y matemático; alcanzaron mayores instrucción y presencia en
Energy Technology Data Exchange (ETDEWEB)
Abe, Katsunori; Kohyama, Akira; Tanaka, Satoru; Namba, C.; Terai, T.; Kunugi, T.; Muroga, Takeo; Hasegawa, Akira; Sagara, A.; Berk, S.; Zinkle, Steven J.; Sze, Dai Kai; Petti, D. A.; Abdou, Mohamed A.; Morley, Neil B.; Kurtz, Richard J.; Snead, Lance L.; Ghoniem, Nasr M.
2008-12-01
This report describes an outline of the activities of the JUPITER-II collaboration (japan-USA program of Irradiation/Integration test for Fusion Research-II), Which has bee carried out through six years (2001-2006) under Phase 4 of the collabroation implemented by Amendment 4 of Annex 1 to the DOE (United States Department of Energy)-MEXT (Ministry of Education ,Culture,Sports,Science and Technology) Cooperation. This program followed the RTNS-II Program (Phase1:1982-4986), the FFTF/MOTA Program (Phase2:1987-1994) and the JUPITER Program (Phase 3: 1995-2000) [1].
Crucial test of the Dirac cosmologies
International Nuclear Information System (INIS)
Steigman, G.
1978-01-01
In a cosmology consistent with the Cosmological Principle (large scale, statistical isotropy and homogeneity of the universe), a Planck spectrum is not preserved as the universe evolves unless the number of photons in a comoving volume is conserved. It is shown that a large class of cosmological models based on Dirac's Large Numbers Hypothesis (LNH) violate this constraint. The observed isotropy and spectral distribution of the microwave background radiation thus provide a crucial test of such cosmologies. After reviewing the LNH, the general evolution of radiation spectra in cosmologies consistent with the cosmological principle is outlined. It is shown that the predicted deviations from a Planck spectrum for Dirac cosmologies (as well as for ''tired-light'' cosmologies) are enormous. The Planckian (or near-Planckian) spectral form for the microwave radiation provides a crucial test, failed by such cosmologies
Axion cold dark matter in nonstandard cosmologies
International Nuclear Information System (INIS)
Visinelli, Luca; Gondolo, Paolo
2010-01-01
We study the parameter space of cold dark matter axions in two cosmological scenarios with nonstandard thermal histories before big bang nucleosynthesis: the low-temperature reheating (LTR) cosmology and the kination cosmology. If the Peccei-Quinn symmetry breaks during inflation, we find more allowed parameter space in the LTR cosmology than in the standard cosmology and less in the kination cosmology. On the contrary, if the Peccei-Quinn symmetry breaks after inflation, the Peccei-Quinn scale is orders of magnitude higher than standard in the LTR cosmology and lower in the kination cosmology. We show that the axion velocity dispersion may be used to distinguish some of these nonstandard cosmologies. Thus, axion cold dark matter may be a good probe of the history of the Universe before big bang nucleosynthesis.
Energy Technology Data Exchange (ETDEWEB)
Schramm, D.N.
1992-03-01
The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ``cold`` and ``hot`` non-baryonic candidates is shown to depend on the assumed ``seeds`` that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.
Energy Technology Data Exchange (ETDEWEB)
Schramm, D.N.
1992-03-01
The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between cold'' and hot'' non-baryonic candidates is shown to depend on the assumed seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.
Perlov, Delia
2017-01-01
This book is an introductory text for all those wishing to learn about modern views of the cosmos. Our universe originated in a great explosion – the big bang. For nearly a century cosmologists have studied the aftermath of this explosion: how the universe expanded and cooled down, and how galaxies were gradually assembled by gravity. The nature of the bang itself has come into focus only relatively recently. It is the subject of the theory of cosmic inflation, which was developed in the last few decades and has led to a radically new global view of the universe. Students and other interested readers will find here a non-technical but conceptually rigorous account of modern cosmological ideas - describing what we know, and how we know it. One of the book's central themes is the scientific quest to find answers to the ultimate cosmic questions: Is the universe finite or infinite? Has it existed forever? If not, when and how did it come into being? Will it ever end? The book is based on the undergraduate cour...
Entropy, matter, and cosmology.
Prigogine, I; Géhéniau, J
1986-09-01
The role of irreversible processes corresponding to creation of matter in general relativity is investigated. The use of Landau-Lifshitz pseudotensors together with conformal (Minkowski) coordinates suggests that this creation took place in the early universe at the stage of the variation of the conformal factor. The entropy production in this creation process is calculated. It is shown that these dissipative processes lead to the possibility of cosmological models that start from empty conditions and gradually build up matter and entropy. Gravitational entropy takes a simple meaning as associated to the entropy that is necessary to produce matter. This leads to an extension of the third law of thermodynamics, as now the zero point of entropy becomes the space-time structure out of which matter is generated. The theory can be put into a convenient form using a supplementary "C" field in Einstein's field equations. The role of the C field is to express the coupling between gravitation and matter leading to irreversible entropy production.
Energy Technology Data Exchange (ETDEWEB)
Verde, Licia; Jimenez, Raul [Institute of Cosmos Sciences, University of Barcelona, IEEC-UB, Martí Franquès, 1, E08028 Barcelona (Spain); Bellini, Emilio [University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Pigozzo, Cassio [Instituto de Física, Universidade Federal da Bahia, Salvador, BA (Brazil); Heavens, Alan F., E-mail: liciaverde@icc.ub.edu, E-mail: emilio.bellini@physics.ox.ac.uk, E-mail: cpigozzo@ufba.br, E-mail: a.heavens@imperial.ac.uk, E-mail: raul.jimenez@icc.ub.edu [Imperial Centre for Inference and Cosmology (ICIC), Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)
2017-04-01
We investigate our knowledge of early universe cosmology by exploring how much additional energy density can be placed in different components beyond those in the ΛCDM model. To do this we use a method to separate early- and late-universe information enclosed in observational data, thus markedly reducing the model-dependency of the conclusions. We find that the 95% credibility regions for extra energy components of the early universe at recombination are: non-accelerating additional fluid density parameter Ω{sub MR} < 0.006 and extra radiation parameterised as extra effective neutrino species 2.3 < N {sub eff} < 3.2 when imposing flatness. Our constraints thus show that even when analyzing the data in this largely model-independent way, the possibility of hiding extra energy components beyond ΛCDM in the early universe is seriously constrained by current observations. We also find that the standard ruler, the sound horizon at radiation drag, can be well determined in a way that does not depend on late-time Universe assumptions, but depends strongly on early-time physics and in particular on additional components that behave like radiation. We find that the standard ruler length determined in this way is r {sub s} = 147.4 ± 0.7 Mpc if the radiation and neutrino components are standard, but the uncertainty increases by an order of magnitude when non-standard dark radiation components are allowed, to r {sub s} = 150 ± 5 Mpc.
Cosmology with exponential potentials
International Nuclear Information System (INIS)
Kehagias, Alex; Kofinas, Georgios
2004-01-01
We examine in the context of general relativity the dynamics of a spatially flat Robertson-Walker universe filled with a classical minimally coupled scalar field φ of exponential potential V(φ) ∼ exp(-μφ) plus pressureless baryonic matter. This system is reduced to a first-order ordinary differential equation for Ω φ (w φ ) or q(w φ ), providing direct evidence on the acceleration/deceleration properties of the system. As a consequence, for positive potentials, passage into acceleration not at late times is generically a feature of the system for any value of μ, even when the late-times attractors are decelerating. Furthermore, the structure formation bound, together with the constraints Ω m0 ∼ 0.25 - 0.3, -1 ≤ w φ0 ≤ -0.6, provides, independently of initial conditions and other parameters, the necessary condition 0 N , while the less conservative constraint -1 ≤ w φ ≤ -0.93 gives 0 N . Special solutions are found to possess intervals of acceleration. For the almost cosmological constant case w φ ∼ -1, the general relation Ω φ (w φ ) is obtained. The generic (nonlinearized) late-times solution of the system in the plane (w φ , Ω φ ) or (w φ , q) is also derived
International Nuclear Information System (INIS)
Schramm, D.N.
1992-03-01
The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the Ω = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ''cold'' and ''hot'' non-baryonic candidates is shown to depend on the assumed ''seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed
International Nuclear Information System (INIS)
Schramm, D.N.
1989-12-01
Nuclear physics has provided one of the 2 critical observational tests of all Big Bang cosmology, namely Big Bang Nucleosynthesis. Furthermore, this same nuclear physics input enables a prediction to be made about one of the most fundamental physics questions of all, the number of elementary particle families. This paper reviews the standard Big Bang Nucleosynthesis arguments. The primordial He abundance is inferred from He--C and He--N and He--O correlations. The strengthened Li constraint as well as 2 D plus 3 He are used to limit the baryon density. This limit is the key argument behind the need for non-baryonic dark matter. The allowed number of neutrino families, N ν , is delineated using the new neutron lifetime value of τ n = 890 ± 4s (τ 1/2 = 10.3 min). The formal statistical result is N ν = 2.6 ± 0.3 (1σ) providing a reasonable fit (1.3σ) to 3 families but making a fourth light (m ν approx-lt 10 MeV) neutrino family exceedingly unlikely (approx-gt 4.7σ) (barring significant systematic errors either in D + 3 He, and Li and/or 4 He and/or τ n ). It is also shown that uncertainties induced by postulating a first-order quark-hadron phase transition do not seriously affect the conclusions. 21 refs., 3 figs
Cosmological quantum entanglement
International Nuclear Information System (INIS)
Martín-Martínez, Eduardo; Menicucci, Nicolas C
2012-01-01
We review recent literature on the connection between quantum entanglement and cosmology, with an emphasis on the context of expanding universes. We discuss recent theoretical results reporting on the production of entanglement in quantum fields due to the expansion of the underlying spacetime. We explore how these results are affected by the statistics of the field (bosonic or fermionic), the type of expansion (de Sitter or asymptotically stationary), and the coupling to spacetime curvature (conformal or minimal). We then consider the extraction of entanglement from a quantum field by coupling to local detectors and how this procedure can be used to distinguish curvature from heating by their entanglement signature. We review the role played by quantum fluctuations in the early universe in nucleating the formation of galaxies and other cosmic structures through their conversion into classical density anisotropies during and after inflation. We report on current literature attempting to account for this transition in a rigorous way and discuss the importance of entanglement and decoherence in this process. We conclude with some prospects for further theoretical and experimental research in this area. These include extensions of current theoretical efforts, possible future observational pursuits, and experimental analogues that emulate these cosmic effects in a laboratory setting. (paper)
Schramm, David N.
1989-01-01
Nuclear physics has provided one of two critical observational tests of all Big Bang cosmology, namely Big Bang Nucleosynthesis. Furthermore, this same nuclear physics input enables a prediction to be made about one of the most fundamental physics questions of all, the number of elementary particle families. The standard Big Bang Nucleosynthesis arguments are reviewed. The primordial He abundance is inferred from He-C and He-N and He-O correlations. The strengthened Li constraint as well as D-2 plus He-3 are used to limit the baryon density. This limit is the key argument behind the need for non-baryonic dark matter. The allowed number of neutrino families, N(nu), is delineated using the new neutron lifetime value of tau(n) = 890 + or - 4s (tau(1/2) = 10.3 min). The formal statistical result is N(nu) = 2.6 + or - 0.3 (1 sigma), providing a reasonable fit (1.3 sigma) to three families but making a fourth light (m(nu) less than or equal to 10 MeV) neutrino family exceedly unlikely (approx. greater than 4.7 sigma). It is also shown that uncertainties induced by postulating a first-order quark-baryon phase transition do not seriously affect the conclusions.
Cosmological helium production simplified
International Nuclear Information System (INIS)
Bernstein, J.; Brown, L.S.; Feinberg, G.
1988-01-01
We present a simplified model of helium synthesis in the early universe. The purpose of the model is to explain clearly the physical ideas relevant to the cosmological helium synthesis, in a manner that does not overlay these ideas with complex computer calculations. The model closely follows the standard calculation, except that it neglects the small effect of Fermi-Dirac statistics for the leptons. We also neglect the temperature difference between photons and neutrinos during the period in which neutrons and protons interconvert. These approximations allow us to express the neutron-proton conversion rates in a closed form, which agrees to 10% accuracy or better with the exact rates. Using these analytic expressions for the rates, we reduce the calculation of the neutron-proton ratio as a function of temperature to a simple numerical integral. We also estimate the effect of neutron decay on the helium abundance. Our result for this quantity agrees well with precise computer calculations. We use our semi-analytic formulas to determine how the predicted helium abundance varies with such parameters as the neutron life-time, the baryon to photon ratio, the number of neutrino species, and a possible electron-neutrino chemical potential. 19 refs., 1 fig., 1 tab
International Nuclear Information System (INIS)
Buchbinder, Evgeny I.; Khoury, Justin; Ovrut, Burt A.
2007-01-01
In this paper, we present a new scenario of the early universe that contains a pre-big bang ekpyrotic phase. By combining this with a ghost condensate, the theory explicitly violates the null energy condition without developing any ghostlike instabilities. Thus the contracting universe goes through a nonsingular bounce and evolves smoothly into the expanding post-big bang phase. The curvature perturbation acquires a scale-invariant spectrum well before the bounce in this scenario. It is sourced by the scale-invariant entropy perturbation engendered by two ekpyrotic scalar fields, a mechanism recently proposed by Lehners et al. Since the background geometry is nonsingular at all times, the curvature perturbation remains nearly constant on superhorizon scales. It emerges from the bounce unscathed and imprints a scale-invariant spectrum of density fluctuations in the matter-radiation fluid at the onset of the hot big bang phase. The ekpyrotic potential can be chosen so that the spectrum has a red tilt, in accordance with the recent data from WMAP. As in the original ekpyrotic scenario, the model predicts a negligible gravity wave signal on all observable scales. As such ''new ekpyrotic cosmology'' provides a consistent and distinguishable alternative to inflation to account for the origin of the seeds of large-scale structure
International Nuclear Information System (INIS)
Reiners, Ch.; Biko, J.; Streffer, C.
2000-05-01
In this project phase II, from 1. April 1996 until 31. March 1998, the activities under the four partial projects entitled 'Therapy and training', 'Biological dosimetry', 'Dosimetry and risk assessment', and 'Coordination and examination authority at Minsk' have been continued and concluded, except for the partial project 'Therapy and training'. (orig./CB) [de
Cosmological implications of light element abundances: theory.
Schramm, D N
1993-06-01
Primordial nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the hot Big Bang cosmological model (versus alternative explanations for the observed Hubble expansion). The standard homogeneous-isotropic calculation fits the light element abundances ranging from 1H at 76% and 4He at 24% by mass through 2H and 3He at parts in 105 down to 7Li at parts in 1010. It is also noted how the recent Large Electron Positron Collider (and Stanford Linear Collider) results on the number of neutrinos (Nnu) are a positive laboratory test of this standard Big Bang scenario. The possible alternate scenario of quark-hadron-induced inhomogeneities is also discussed. It is shown that when this alternative scenario is made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density (Omegab) remain approximately the same as in the standard homogeneous case, thus adding to the robustness of the standard model and the conclusion that Omegab approximately 0.06. This latter point is the driving force behind the need for nonbaryonic dark matter (assuming total density Omegatotal = 1) and the need for dark baryonic matter, since the density of visible matter Omegavisible < Omegab. The recent Population II B and Be observations are also discussed and shown to be a consequence of cosmic ray spallation processes rather than primordial nucleosynthesis. The light elements and Nnu successfully probe the cosmological model at times as early as 1 sec and a temperature (T) of approximately 10(10) K (approximately 1 MeV). Thus, they provided the first quantitative arguments that led to the connections of cosmology to nuclear and particle physics.
International Nuclear Information System (INIS)
Rami, El-Nabulsi Ahmad
2009-01-01
Higher dimensional cosmological implications of a decay law for the cosmological constant term are analyzed. Three independent cosmological models are explored mainly: 1) In the first model, the effective cosmological constant was chosen to decay with times like Δ effective = Ca -2 + D(b/a I ) 2 where a I is an arbitrary scale factor characterizing the isotropic epoch which proceeds the graceful exit period. Further, the extra-dimensional scale factor decays classically like b(t) approx. a x (t), x is a real negative number. 2) In the second model, we adopt in addition to Δ effective = Ca -2 + D(b/a I ) 2 the phenomenological law b(t) = a(t)exp( -Qt) as we expect that at the origin of time, there is no distinction between the visible and extra dimensions; Q is a real number. 3) In the third model, we study a Δ - decaying extra-dimensional cosmology with a static traversable wormhole in which the four-dimensional Friedmann-Robertson-Walker spacetime is subject to the conventional perfect fluid while the extra-dimensional part is endowed by an exotic fluid violating strong energy condition and where the cosmological constant in (3+n+1) is assumed to decays like Δ(a) = 3Ca -2 . The three models are discussed and explored in some details where many interesting points are revealed. (author)
An introduction to the PISC II project - programme for the inspection of steel components
International Nuclear Information System (INIS)
Nichols, R.; McDonald, N.R.
1987-01-01
The paper describes the work of the Plate Inspection Steering Committee (PISC) on the non-destructive examination of reactor pressure vessel steels. A description is given of the PISC I exercise on flaw measurements in test plates, including the PISC procedure and the alternative procedures in the PISC I exercise. The motivation for a PISC II programme is described, together with the objectives and terms of reference of PISC II. (U.K.)
Cosmological tests of modified gravity.
Koyama, Kazuya
2016-04-01
We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard [Formula: see text]CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.
REM - the Shape of Potentials for f(R) Theories in Cosmology and Tachyons
Vulcanov, Dumitru N; Sporea, Ciprian A
2014-01-01
We investigated the reverse engineering method (REM) for constructing the potential of the scalar field in cosmological theories based on metric f(R) gravity and Friedman Robertson Walker (FRW) metric. Then transposing the new field and Friedman equations in an algebraic computing special library (in Maple + GrTennsorII platform) we graphically investigate the shape of the potentials in terms of the scalar field in at least two type of cosmology with exponential and linear scale factor expansion. Some perspectives and conclusions relating these results with tachyonic cosmology theories are noticed.
Fossil Groups as Cosmological Labs
D'Onghia, Elena
Optical and X-ray measurements of fossil groups (FGs) suggest that they are old and relaxed systems. If FGs are assembled at higher redshift, there is enough time for intermediate-luminosity galaxies to merge, resulting in the formation of the brightest group galaxy (BGG). We carry out the first, systematic study of a large sample of FGs, the "FOssil Group Origins'' (FOGO) based on an International Time Project at the Roque de los Muchachos Observatory. For ten FOGO FGs we have been awarded time at SUZAKU Telescope to measure the temperature of the hot intragroup gas (IGM). For these systems we plan to evaluate and correlate their X-ray luminosity and X-ray temperature, Lx-Tx, optical luminosity and X-ray temperature, Lopt-Tx, and group velocity dispersion with their X-ray temperature, sigma V-Tx, as compared to the non fossil systems. By combining these observations with state-of-art cosmological hydrodynamical simulations we will open a new window into the study of the IGM and the nature of fossil systems. Our proposed work will be of direct relevance for the understanding and interpretation of data from several NASA science missions. Specifically, the scaling relations obtained from these data combined with our predictions obtained using state-of-the-art hydrodynamical simulation numerical adopting a new hydrodynamical scheme will motivate new proposal on CHANDRA X-ray telescope for fossil groups and clusters. We will additionally create a public Online Planetarium Show. This will be an educational site, containing an interactive program called: "A Voyage to our Universe''. In the show we will provide observed images of fossil groups and similar images and movies obtained from the numerical simulations showing their evolution. The online planetarium show will be a useful reference and an interactive educational tool for both students and the public.
Coherent semiclassical states for loop quantum cosmology
International Nuclear Information System (INIS)
Corichi, Alejandro; Montoya, Edison
2011-01-01
The spatially flat Friedmann-Robertson-Walker cosmological model with a massless scalar field in loop quantum cosmology admits a description in terms of a completely solvable model. This has been used to prove that: (i) the quantum bounce that replaces the big bang singularity is generic; (ii) there is an upper bound on the energy density for all states, and (iii) semiclassical states at late times had to be semiclassical before the bounce. Here we consider a family of exact solutions to the theory, corresponding to generalized coherent Gaussian and squeezed states. We analyze the behavior of basic physical observables and impose restrictions on the states based on physical considerations. These turn out to be enough to select, from all the generalized coherent states, those that behave semiclassical at late times. We study then the properties of such states near the bounce where the most 'quantum behavior' is expected. As it turns out, the states remain sharply peaked and semiclassical at the bounce and the dynamics is very well approximated by the ''effective theory'' throughout the time evolution. We compare the semiclassicality properties of squeezed states to those of the Gaussian semiclassical states and conclude that the Gaussians are better behaved. In particular, the asymmetry in the relative fluctuations before and after the bounce are negligible, thus ruling out claims of so-called 'cosmic forgetfulness'.
Wind River Watershed Restoration Project, Segment II, 2000-2002 Annual Report.
Energy Technology Data Exchange (ETDEWEB)
Bair, Brian; Olegario, Anthony; Powers, Paul
2002-06-01
This document represents work conducted as part of the Wind River Watershed Restoration Project during its second year of funding through the Bonneville Power Administration (BPA). The project is a comprehensive effort involving public and private entities seeking to restore water quality and fishery resources in the basin through cooperative actions. Project elements include coordination, watershed assessment, restoration, monitoring, and education. Entities involved with implementing project components are the Underwood Conservation District (UCD), USDA Forest Service (USFS), U.S. Geological Survey - Columbia River Research Lab (USGS-CRRL), and WA Department of Fish & Wildlife (WDFW).
Partial rip scenario - a cosmology with a growing cosmological term
International Nuclear Information System (INIS)
Stefancic, H.
2004-01-01
A cosmology with the growing cosmological term is considered. If there is no exchange of energy between vacuum and matter components, the requirement of general covariance implies the time dependence of the gravitational constant G. Irrespectively of the exact functional form of the cosmological term growth, the universe ends in a de Sitter regime with a constant asymptotic Λ, but vanishing G. Although there is no divergence of the scale factor in finite time, such as in the 'Big Rip' scenario, gravitationally bound systems eventually become unbound. In the case of systems bound by non-gravitational forces, there is no unbounding effect, as the asymptotic Λ is insufficiently large to disturb these systems
Phase portraits of general f(T) cosmology
Awad, A.; El Hanafy, W.; Nashed, G. G. L.; Saridakis, Emmanuel N.
2018-02-01
We use dynamical system methods to explore the general behaviour of f(T) cosmology. In contrast to the standard applications of dynamical analysis, we present a way to transform the equations into a one-dimensional autonomous system, taking advantage of the crucial property that the torsion scalar in flat FRW geometry is just a function of the Hubble function, thus the field equations include only up to first derivatives of it, and therefore in a general f(T) cosmological scenario every quantity is expressed only in terms of the Hubble function. The great advantage is that for one-dimensional systems it is easy to construct the phase space portraits, and thus extract information and explore in detail the features and possible behaviours of f(T) cosmology. We utilize the phase space portraits and we show that f(T) cosmology can describe the universe evolution in agreement with observations, namely starting from a Big Bang singularity, evolving into the subsequent thermal history and the matter domination, entering into a late-time accelerated expansion, and resulting to the de Sitter phase in the far future. Nevertheless, f(T) cosmology can present a rich class of more exotic behaviours, such as the cosmological bounce and turnaround, the phantom-divide crossing, the Big Brake and the Big Crunch, and it may exhibit various singularities, including the non-harmful ones of type II and type IV. We study the phase space of three specific viable f(T) models offering a complete picture. Moreover, we present a new model of f(T) gravity that can lead to a universe in agreement with observations, free of perturbative instabilities, and applying the Om(z) diagnostic test we confirm that it is in agreement with the combination of SNIa, BAO and CMB data at 1σ confidence level.
The Abacus Cosmos: A Suite of Cosmological N-body Simulations
Garrison, Lehman H.; Eisenstein, Daniel J.; Ferrer, Douglas; Tinker, Jeremy L.; Pinto, Philip A.; Weinberg, David H.
2018-06-01
We present a public data release of halo catalogs from a suite of 125 cosmological N-body simulations from the ABACUS project. The simulations span 40 wCDM cosmologies centered on the Planck 2015 cosmology at two mass resolutions, 4 × 1010 h ‑1 M ⊙ and 1 × 1010 h ‑1 M ⊙, in 1.1 h ‑1 Gpc and 720 h ‑1 Mpc boxes, respectively. The boxes are phase-matched to suppress sample variance and isolate cosmology dependence. Additional volume is available via 16 boxes of fixed cosmology and varied phase; a few boxes of single-parameter excursions from Planck 2015 are also provided. Catalogs spanning z = 1.5 to 0.1 are available for friends-of-friends and ROCKSTAR halo finders and include particle subsamples. All data products are available at https://lgarrison.github.io/AbacusCosmos.
Summary report of Japan-US joint project. JUPITER-II. FuY 2001 - 2006
International Nuclear Information System (INIS)
Abe, K.; Kohyama, A.; Tanaka, S.; Muroga, T.; Namba, C.; Sze, D.K.
2008-03-01
This report summarizes the scientific accomplishments achieved through the JUPITER-II Japan-US Collaboration Program. The JUPITER-II collaboration (Japan-USA Program of Irradiation/Integration Test for Fusion Research -II) has been carried out through six years (2001-2006) under Phase 4 of the collaboration implemented by Amendment 4 of Annex I to the MEXT (Ministry of Education, Culture, Sports, Science and Technology)-DOE (United States Department of Energy) Cooperation. This program followed the RTNS-II Program (Phase 1: 1982-1986), the FFTF/MOTA Program (Phase 2: 1987-1994) and the JUPITER Program (Phase 3: 1995-2000). The JUPITER-II collaboration was established to provide the scientific foundations for understanding the integrated behavior of blanket materials combinations operating under conditions characteristic of fusion reactors, including interactive neutron irradiation effects, high temperature coolant flow phenomena, heat and mass transport in blanket materials, and coolant chemistry and its interactions with surrounding materials. The scientific concept of this program is to study the key technology in macroscopic system integration for advanced blanket based on an understanding of the relevant mechanics at the microscopic level. The 44 of the presented papers are indexed individually. (J.P.N.)
Cosmological tests of coupled Galileons
International Nuclear Information System (INIS)
Brax, Philippe; Burrage, Clare; Davis, Anne-Christine; Gubitosi, Giulia
2015-01-01
We investigate the cosmological properties of Galileon models which admit Minkowski space as a stable solution in vacuum. This is motivated by stable, positive tension brane world constructions that give rise to Galileons. We include both conformal and disformal couplings to matter and focus on constraints on the theory that arise because of these couplings. The disformal coupling to baryonic matter is extremely constrained by astrophysical and particle physics effects. The disformal coupling to photons induces a cosmological variation of the speed of light and therefore distorsions of the Cosmic Microwave Background spectrum which are known to be very small. The conformal coupling to baryons leads to a variation of particle masses since Big Bang Nucleosynthesis which is also tightly constrained. We consider the background cosmology of Galileon models coupled to Cold Dark Matter (CDM), photons and baryons and impose that the speed of light and particle masses respect the observational bounds on cosmological time scales. We find that requiring that the equation of state for the Galileon models must be close to -1 now restricts severely their parameter space and can only be achieved with a combination of the conformal and disformal couplings. This leads to large variations of particle masses and the speed of light which are not compatible with observations. As a result, we find that cosmological Galileon models are viable dark energy theories coupled to dark matter but their couplings, both disformal and conformal, to baryons and photons must be heavily suppressed making them only sensitive to CDM
Relic gravitons and viscous cosmologies
International Nuclear Information System (INIS)
Cataldo, Mauricio; Mella, Patricio
2006-01-01
Previously it was shown that there exists a class of viscous cosmological models which violate the dominant energy condition for a limited amount of time after which they are smoothly connected to the ordinary radiation era (which preserves the dominant energy conditions). This violation of the dominant energy condition at an early cosmological epoch may influence the slopes of energy spectra of relic gravitons that might be of experimental relevance. However, the bulk viscosity coefficient of these cosmologies became negative during the ordinary radiation era, and then the entropy of the sources driving the geometry decreases with time. We show that in the presence of viscous sources with a linear barotropic equation of state p=γρ we get viscous cosmological models with positive bulk viscous stress during all their evolution, and hence the matter entropy increases with the expansion time. In other words, in the framework of viscous cosmologies, there exist isotropic models compatible with the standard second law of thermodynamics which also may influence the slopes of energy spectra of relic gravitons
PREPARATION AIDS FOR THE DEVELOPMENT OF CATEGORY II QUALITY ASSURANCE PROJECT PLANS
Data collection activities performed for the Risk Reduction Engineering aboratory (RREL) of the U.S. Environmental Protection Agency are divided into tour categories, depending on the intended use of the data. uality Assurance (QA) Project Plans are written to ensure that project...
Stenner, A. Jackson; And Others
This document contains the second of five volumes reporting the activities and results of a career education evaluation project conducted to accomplish the following two objectives: (1) to improve the quality of evaluations by career education projects funded by the United States Office of Career Education (OCE) through the provision of technical…
International Nuclear Information System (INIS)
2005-06-01
Horonobe Underground Research Laboratory Project is planned for over 20 years to establish the scientific and technical basis for the underground disposal of high-level radioactive wastes in Japan. The investigations are conducted by JNC in three phases, from the surface (Phase I), during the construction of the underground facilities (Phase II), and using the facilities (Phase III). This report concerns the investigation plans for Phase II. During excavation of shafts and drifts, detailed geological and borehole investigation will be conducted and the geological model constructed in Phase I is evaluated and revised by newly acquired data of geophysical and geological environment. Detailed in-situ experiments, as well as the effects of shaft excavation, are also done to study long-term changes, rock properties, groundwater flow and chemistry to ensure the reliability of repository technology and establish safety assessment methodology. (S. Ohno)
Second viscosity effects in cosmology
International Nuclear Information System (INIS)
Potupa, A.S.
1978-01-01
The object of the investigation is to draw attention to two important aspects in the choice of a substance model, namely an allowance for the viscosity and behaviour of the metrics at the later stages of cosmological evolution. It is shown that in homogeneous cosmological models taking into account the viscosity there are solutions which realize interpolation between the Fridman and steady-state regimes. In a closed model a solution is obtained which corresponds to the ''curvature compensation'' regime with an unboundedly increasing radius. The problem of compensation of singularity at t → o is discussed as well as the choice of the equations of state for the early (hadron) stages of cosmological evolution in connection with the hydrodynamic theory of multiple hadron production
International Nuclear Information System (INIS)
Niedermann, Florian; Schneider, Robert
2015-01-01
We derive the modified Friedmann equations for a generalization of the Dvali-Gabadadze-Porrati (DGP) model in which the brane has one additional compact dimension. The main new feature is the emission of gravitational waves into the bulk. We study two classes of solutions: first, if the compact dimension is stabilized, the waves vanish and one exactly recovers DGP cosmology. However, a stabilization by means of physical matter is not possible for a tension-dominated brane, thus implying a late time modification of 4D cosmology different from DGP. Second, for a freely expanding compact direction, we find exact attractor solutions with zero 4D Hubble parameter despite the presence of a 4D cosmological constant. The model hence constitutes an explicit example of dynamical degravitation at the full nonlinear level. Without stabilization, however, there is no 4D regime and the model is ruled out observationally, as we demonstrate explicitly by comparing to supernova data
Quantum gravity and quantum cosmology
Papantonopoulos, Lefteris; Siopsis, George; Tsamis, Nikos
2013-01-01
Quantum gravity has developed into a fast-growing subject in physics and it is expected that probing the high-energy and high-curvature regimes of gravitating systems will shed some light on how to eventually achieve an ultraviolet complete quantum theory of gravity. Such a theory would provide the much needed information about fundamental problems of classical gravity, such as the initial big-bang singularity, the cosmological constant problem, Planck scale physics and the early-time inflationary evolution of our Universe. While in the first part of this book concepts of quantum gravity are introduced and approached from different angles, the second part discusses these theories in connection with cosmological models and observations, thereby exploring which types of signatures of modern and mathematically rigorous frameworks can be detected by experiments. The third and final part briefly reviews the observational status of dark matter and dark energy, and introduces alternative cosmological models. ...
Working group report: Cosmology and astroparticle physics
Indian Academy of Sciences (India)
This is the report of the cosmology and astroparticle physics working group ... origin of the accelerating Universe: Dark energy and particle cosmology by Y-Y Keum, .... Neutrino oscillations with two and three mass varying supernova neutrinos ...
The current status of observational cosmology
Indian Academy of Sciences (India)
in quality, quantity and the scope of cosmological observations. The measurement .... In this article, we limit our attention to the simplest case of a cosmological ... On the large angular scales, the CMB anisotropy directly probes the primordial.
A philosophy for big-bang cosmology.
McCrea, W H
1970-10-03
According to recent developments in cosmology we seem bound to find a model universe like the observed universe, almost independently of how we suppose it started. Such ideas, if valid, provide fresh justification for the procedures of current cosmological theory.
Energy Technology Data Exchange (ETDEWEB)
Irastorza, I.G.; Aznar, F.; Castel, J., E-mail: igor.irastorza@cern.ch, E-mail: faznar@unizar.es, E-mail: jfcastel@unizar.es [Grupo de Física Nuclear y Astropartículas, Departamento de Física Teórica, Universidad de Zaragoza, C/ P. Cerbuna 12, Zaragoza, 50009 Spain (Spain); and others
2016-01-01
As part of the T-REX project, a number of R and D and prototyping activities have been carried out during the last years to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches like double beta decay, axion research and low-mass WIMP searches. While in the companion paper we focus on double beta decay, in this paper we focus on the results regarding the search for dark matter candidates, both axions and WIMPs. Small (few cm wide) ultra-low background Micromegas detectors are used to image the axion-induced x-ray signal expected in axion helioscopes like the CERN Axion Solar Telescope (CAST) experiment. Background levels as low as 0.8 × 10{sup −6} counts keV{sup −1} cm{sup −2} s{sup −1} have already been achieved in CAST while values down to ∼10{sup −7} counts keV{sup −1} cm{sup −2} s{sup −1} have been obtained in a test bench placed underground in the Laboratorio Subterráneo de Canfranc (LSC). Prospects to consolidate and further reduce these values down to ∼10{sup −8} counts keV{sup −1} cm{sup −2} s{sup −1} will be described. Such detectors, placed at the focal point of x-ray telescopes in the future International Axion Observatory (IAXO), would allow for 10{sup 5} better signal-to-noise ratio than CAST, and search for solar axions with g{sub a}γ down to few 10{sup 12} GeV{sup −1}, well into unexplored axion parameter space. In addition, a scaled-up version of these TPCs, properly shielded and placed underground, can be competitive in the search for low-mass WIMPs. The TREX-DM prototype, with ∼ 0.300 kg of Ar at 10 bar, or alternatively ∼ 0.160 kg of Ne at 10 bar, and energy threshold well below 1 keV, has been built to test this concept. We will describe the main technical solutions developed, as well as the results from the commissioning phase on surface. The anticipated sensitivity of this technique might reach ∼10{sup −44} cm{sup 2} for
Averaging in spherically symmetric cosmology
International Nuclear Information System (INIS)
Coley, A. A.; Pelavas, N.
2007-01-01
The averaging problem in cosmology is of fundamental importance. When applied to study cosmological evolution, the theory of macroscopic gravity (MG) can be regarded as a long-distance modification of general relativity. In the MG approach to the averaging problem in cosmology, the Einstein field equations on cosmological scales are modified by appropriate gravitational correlation terms. We study the averaging problem within the class of spherically symmetric cosmological models. That is, we shall take the microscopic equations and effect the averaging procedure to determine the precise form of the correlation tensor in this case. In particular, by working in volume-preserving coordinates, we calculate the form of the correlation tensor under some reasonable assumptions on the form for the inhomogeneous gravitational field and matter distribution. We find that the correlation tensor in a Friedmann-Lemaitre-Robertson-Walker (FLRW) background must be of the form of a spatial curvature. Inhomogeneities and spatial averaging, through this spatial curvature correction term, can have a very significant dynamical effect on the dynamics of the Universe and cosmological observations; in particular, we discuss whether spatial averaging might lead to a more conservative explanation of the observed acceleration of the Universe (without the introduction of exotic dark matter fields). We also find that the correlation tensor for a non-FLRW background can be interpreted as the sum of a spatial curvature and an anisotropic fluid. This may lead to interesting effects of averaging on astrophysical scales. We also discuss the results of averaging an inhomogeneous Lemaitre-Tolman-Bondi solution as well as calculations of linear perturbations (that is, the backreaction) in an FLRW background, which support the main conclusions of the analysis
Particle accelerators test cosmological theory
International Nuclear Information System (INIS)
Schramm, D.N.; Steigman, G.
1988-01-01
Over the past decade two subfields of science, cosmology and elementary-particle physics, have become married in a symbiotic relationship that has produced a number of exciting offspring. These offspring are beginning to yield insights on the creation of spacetime and matter at epochs as early as 10 to the minus 43 to 10 to the minus 35 second after the birth of the universe in the primordial explosion known as the big bang. Important clues to the nature of the big bang itself may even come from a theory currently under development, known as the ultimate theory of everything (T.E.O.). A T.E.O. would describe all the interactions among the fundamental particles in a single bold stroke. Now that cosmology ahs begun to make predictions about elementary-particle physics, it has become conceivable that those cosmological predictions could be checked with carefully controlled accelerator experiments. It has taken more than 10 years for accelerators to reach the point where they can do the appropriate experiments, but the experiments are now in fact in progress. The preliminary results confirm the predictions of cosmology. The cosmological prediction the authors have been concerned with pertains to setting limits on the number of fundamental particles of matter. It appears that there are 12 fundamental particles, as well as their corresponding antiparticles. Six of the fundamental particles are quarks. The other six are leptons. The 12 particles are grouped in three families, each family consisting of four members. Cosmology suggests there must be a finite number of families and, further limits the possible range of to small values: only three or at most four families exist. 7 figs
Loop quantum cosmology and spin foams
International Nuclear Information System (INIS)
Ashtekar, Abhay; Campiglia, Miguel; Henderson, Adam
2009-01-01
Loop quantum cosmology (LQC) is used to provide concrete evidence in support of the general paradigm underlying spin foam models (SFMs). Specifically, it is shown that: (i) the physical inner product in the timeless framework equals the transition amplitude in the deparameterized theory; (ii) this quantity admits a vertex expansion a la SFMs in which the M-th term refers just to M volume transitions, without any reference to the time at which the transition takes place; (iii) the exact physical inner product is obtained by summing over just the discrete geometries; no 'continuum limit' is involved; and, (iv) the vertex expansion can be interpreted as a perturbative expansion in the spirit of group field theory. This sum over histories reformulation of LQC also addresses certain other issues which are briefly summarized.
Linux toys II 9 Cool New Projects for Home, Office, and Entertainment
Negus, Christopher
2006-01-01
Builds on the success of the original Linux Toys (0-7645-2508-5) and adds projects using different Linux distributionsAll-new toys in this edition include a car computer system with built-in entertainment and navigation features, bootable movies, a home surveillance monitor, a LEGO Mindstorms robot, and a weather mapping stationIntroduces small business opportunities with an Internet radio station and Internet caf ̌projectsCompanion Web site features specialized hardware drivers, software interfaces, music and game software, project descriptions, and discussion forumsIncludes a CD-ROM with scr
UCH-II, private power project, Dera Murad Jamali, Pakistan. Export trade information
Energy Technology Data Exchange (ETDEWEB)
1993-01-01
Energy Resources International and Power Development Company of Pakistan in association with General Electric Corporation, Inc. offers to build, finance, own and operate a 500+ MW combined cycle natural gas electric power plant, near Dera Murad Jamali, Pakistan. The basis for the undertaking is a carefully balanced and integrated series of contracts for fuel, power purchase, and implementation of the proposed project. The contracts would be established between the Government of Pakistan (GOP), its agencies and instrumentalities, Energy Resources International with Power Development Company and its associates, and a Project Company organized specifically for the undertaking. The report describes the project.
Energy Technology Data Exchange (ETDEWEB)
NONE
1979-10-01
Among the EDS, H-Coal and SRC-2 lined up in the coal liquefaction project of the U.S., the SRC is aimed at producing 6,000 t/day as a module for a 30,000 t/day commercial plant. They expect Ash contents (iron, sulfur, etc.) in coal without basically using catalysts. The products are applicable to fuels for electricity and gas for the moment. In the element technology, there are some problems in manufacturing hydrogen by gasification of residuals as well as in slurry systems, reaction towers, etc.. In the 30,000 ton commercial plant, the coal-liquefied oil costs $19.89/bbl (price as of 1978) assuming coal costs $29.47; therefore, the feasibility is strong as a substitute for petroleum. Japan's share for the required funds will be 86.8 billion yen (if 250 yen per dollar). Since the kinds of coal are conceivably increased in number through the improvement of the process, the Pacific rim countries and these which lie on the Indian Ocean are assumed to be the major coal producing countries for Japan. The stability in storage of coal-liquefied oil is experimentally excellent, as is the compatibility with petroleum products for example. Great results can be expected in the technical know-how and the spread of element technology for Japan. (NEDO)
International Nuclear Information System (INIS)
Thas, Koen
2006-01-01
In Am. Math. Monthly (73 1-23 (1966)), Kac asked his famous question 'Can one hear the shape of a drum?', which was eventually answered negatively in Gordon et al (1992 Invent. Math. 110 1-22) by construction of planar isospectral pairs. Giraud (2005 J. Phys. A: Math. Gen. 38 L477-83) observed that most of the known examples can be generated from solutions of a certain equation which involves a set of involutions of an n-dimensional projective space over some finite field. He then generated all possible solutions for n = 2, when the involutions fix the same number of points. In Thas (2006 J. Phys. A: Math. Gen. 39 L385-8) we showed that no other examples arise for any other dimension, still assuming that the involutions fix the same number of points. In this paper we study the problem for involutions not necessarily fixing the same number of points, and solve the problem completely
Energy Technology Data Exchange (ETDEWEB)
NONE
1979-10-01
Among the EDS, H-Coal and SRC-2 lined up in the coal liquefaction project of the U.S., the SRC is aimed at producing 6,000 t/day as a module for a 30,000 t/day commercial plant. They expect Ash contents (iron, sulfur, etc.) in coal without basically using catalysts. The products are applicable to fuels for electricity and gas for the moment. In the element technology, there are some problems in manufacturing hydrogen by gasification of residuals as well as in slurry systems, reaction towers, etc.. In the 30,000 ton commercial plant, the coal-liquefied oil costs $19.89/bbl (price as of 1978) assuming coal costs $29.47; therefore, the feasibility is strong as a substitute for petroleum. Japan's share for the required funds will be 86.8 billion yen (if 250 yen per dollar). Since the kinds of coal are conceivably increased in number through the improvement of the process, the Pacific rim countries and these which lie on the Indian Ocean are assumed to be the major coal producing countries for Japan. The stability in storage of coal-liquefied oil is experimentally excellent, as is the compatibility with petroleum products for example. Great results can be expected in the technical know-how and the spread of element technology for Japan. (NEDO)
Cosmological dynamics of extended chameleons
International Nuclear Information System (INIS)
Tamanini, Nicola; Wright, Matthew
2016-01-01
We investigate the cosmological dynamics of the recently proposed extended chameleon models at both background and linear perturbation levels. Dynamical systems techniques are employed to fully characterize the evolution of the universe at the largest distances, while structure formation is analysed at sub-horizon scales within the quasi-static approximation. The late time dynamical transition from dark matter to dark energy domination can be well described by almost all extended chameleon models considered, with no deviations from ΛCDM results at both background and perturbation levels. The results obtained in this work confirm the cosmological viability of extended chameleons as alternative dark energy models.
Brane cosmology with curvature corrections
International Nuclear Information System (INIS)
Kofinas, Georgios; Maartens, Roy; Papantonopoulos, Eleftherios
2003-01-01
We study the cosmology of the Randall-Sundrum brane-world where the Einstein-Hilbert action is modified by curvature correction terms: a four-dimensional scalar curvature from induced gravity on the brane, and a five-dimensional Gauss-Bonnet curvature term. The combined effect of these curvature corrections to the action removes the infinite-density big bang singularity, although the curvature can still diverge for some parameter values. A radiation brane undergoes accelerated expansion near the minimal scale factor, for a range of parameters. This acceleration is driven by the geometric effects, without an inflation field or negative pressures. At late times, conventional cosmology is recovered. (author)
Baryon symmetric big bang cosmology
International Nuclear Information System (INIS)
Stecker, F.W.
1978-01-01
It is stated that the framework of baryon symmetric big bang (BSBB) cosmology offers our greatest potential for deducting the evolution of the Universe because its physical laws and processes have the minimum number of arbitrary assumptions about initial conditions in the big-bang. In addition, it offers the possibility of explaining the photon-baryon ratio in the Universe and how galaxies and galaxy clusters are formed. BSBB cosmology also provides the only acceptable explanation at present for the origin of the cosmic γ-ray background radiation. (author)
Cosmological dynamics of extended chameleons
Energy Technology Data Exchange (ETDEWEB)
Tamanini, Nicola [Institut de Physique Théorique, CEA-Saclay, CNRS UMR 3681, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France); Wright, Matthew, E-mail: nicola.tamanini@cea.fr, E-mail: matthew.wright.13@ucl.ac.uk [Department of Mathematics, University College London, Gower Street, London, WC1E 6BT (United Kingdom)
2016-04-01
We investigate the cosmological dynamics of the recently proposed extended chameleon models at both background and linear perturbation levels. Dynamical systems techniques are employed to fully characterize the evolution of the universe at the largest distances, while structure formation is analysed at sub-horizon scales within the quasi-static approximation. The late time dynamical transition from dark matter to dark energy domination can be well described by almost all extended chameleon models considered, with no deviations from ΛCDM results at both background and perturbation levels. The results obtained in this work confirm the cosmological viability of extended chameleons as alternative dark energy models.
The Higgs Portal and Cosmology
Energy Technology Data Exchange (ETDEWEB)
Assamagan, Ketevi [Brookhaven National Lab. (BNL), Upton, NY (United States); Chen, Chien-Yi [Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada); Univ. of Victoria, BC (Canada); Chou, John Paul [Rutgers Univ., Piscataway, NJ (United States); Curtin, David [Univ. of Maryland, College Park, MD (United States); Fedderke, Michael A. [Univ. of Chicago, IL (United States); Gershtein, Yuri [Rutgers Univ., Piscataway, NJ (United States); He, Xiao-Gang [Shanghai Jiao Tong Univ. (China); Klute, Markus [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Kozaczuk, Jonathon [TRIUMF, Vancouver, BC (Canada); Kotwal, Ashutosh [Duke Univ., Durham, NC (United States); Lowette, Steven [Vrije Univ., Brussels (Belgium); No, Jose Miguel [Univ. of Sussex, Brighton (United Kingdom); Plehn, Tilman [Heidelberg Univ. (Germany); Qian, Jianming [Univ. of Michigan, Ann Arbor, MI (United States); Ramsey-Musolf, Michael [Univ. of Massachusetts, Amherst, MA (United States); Safonov, Alexei [Texas A & M Univ., College Station, TX (United States); Shelton, Jessie [Univ. of Illinois, Urbana-Champaign, IL (United States); Spannowsky, Michael [Durham Univ. (United Kingdom); Su, Shufang [Univ. of Arizona, Tucson, AZ (United States); Walker, Devin G. E. [Univ. of Washington, Seattle, WA (United States); Willocq, Stephane [Univ. of Massachusetts, Amherst, MA (United States); Winslow, Peter [Univ. of Massachusetts, Amherst, MA (United States)
2016-04-18
Higgs portal interactions provide a simple mechanism for addressing two open problems in cosmology: dark matter and the baryon asymmetry. In the latter instance, Higgs portal interactions may contain the ingredients for a strong first-order electroweak phase transition as well as new CP-violating interactions as needed for electroweak baryogenesis. These interactions may also allow for a viable dark matter candidate. We survey the opportunities for probing the Higgs portal as it relates to these questions in cosmology at the LHC and possible future colliders.
Cosmology in the plasma universe
International Nuclear Information System (INIS)
Alfven, H.
1987-05-01
Space observations have opened the spectral regions of X-rays and γ-rays, which are produced by plasma processes. The Plasma Universe derived from observations in these regions is drastically different from the now generally accepted 'Visual Light Universe' based on visual light observations alone. Historically this transitions can be compared only to the transition from the geocentric to the heliocentric cosmology. The purpose of this paper is to discuss what criteria a cosmological theory must satisfy in order to be acceptable in the Plasma Universe. (author)
Energy Technology Data Exchange (ETDEWEB)
Zhang, Xiaoliang [World Resources Inst. (WRI), Washington, DC (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-09-25
This effort is designed to expedite learnings from existing and planned large demonstration projects and their associated research through effective knowledge sharing among participants in the US and China.