DOCSLIB.ORG

Probing the Foundations of the Standard Cosmological Model

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Probing the Foundations of the Standard Cosmological Model Departamento de F´ısicaTe´oricae Instituto de F´ısicaTe´orica Universidad Aut´onomade Madrid PROBING THE FOUNDATIONS OF THE STANDARD COSMOLOGICAL MODEL Memoria de Tesis Doctoral presentada por Miguel Zumalac´arreguiP´erez para optar al t´ıtulode Doctor en Ciencias F´ısicas Programa de Doctorado de F´ısicaTe´orica Trabajo supervisado por los Doctores Juan Garc´ıa-BellidoCapdevila, Profesor Titular del Departamento de F´ısicaTe´orica,Universidad Aut´onomade Madrid Pilar Ruiz-Lapuente, Investigadora Cient´ıfica del Instituto de F´ısicaFundamental, Consejo Superior de Investigaciones Cient´ıficas y Tomi S. Koivisto, Investigador Postdoctoral del Instituto de Astrof´ısicaTe´orica,Universidad de Oslo. Octubre de 2012 ii A mis padres. iii iv Contents Statement ix Preface xi Resumen y Conclusiones xv Acknowledgements xix Notation and Acronyms xxi I Foundations1 1 The Standard Cosmological Model3 1.1 Ingredients and Preparation4 1.1.1 General Relativity4 1.1.2 Metric Ansatz: The Copernican Principle5 1.1.3 Inflation: Symmetry and Initial Conditions6 1.1.4 Standard and Dark Matter7 1.1.5 The Cosmological Constant7 1.2 The Need to Go Beyond8 1.2.1 Theoretical Issues8 1.2.2 Observational Reasons 10 1.3 Exotic Tastes and Alternative Recipes 12 1.3.1 Inhomogeneous Models 12 1.3.2 Dynamical Dark Energy 14 1.3.3 Modified Gravity 16 2 Observational Probes of Cosmology 23 2.1 Geometry and Dynamics 24 2.2 Primordial Nucleosynthesis 26 2.3 Cosmic Microwave Background Radiation 26 2.3.1 CMB Distance Priors 28 2.4 Large Scale Structure 29 2.4.1 The Baryon Acoustic Oscillation Scale 31 2.4.2 Other LSS Probes 34 2.5 Type Ia Supernovae 35 v CONTENTS 2.5.1 Local Expansion Rate 37 2.6 Local Gravity Tests 37 II Results 39 3 Large Scale Homogeneity and Non-Copernican Void Models 41 3.1 Lema^ıtre-Tolman-Bondi Models 43 3.1.1 The Adiabatic GBH Model 46 3.2 The Baryon Acoustic Scale in LTB Universes 47 3.2.1 Free-falling Scales in the LTB Metric 48 3.2.2 BAO Scale Evolution Beyond Zero Order 50 3.2.3 The Physical BAO Scale at Early Times and on the Lightcone 51 3.2.4 Comparison with the Observed BAO Scale 52 3.2.5 The Alcock-Paczynski Effect in LTB Models 54 3.3 Analysis and Results 54 3.3.1 Observational Data 55 3.3.2 MCMC Analysis 58 3.3.3 Homogeneous Models 59 3.3.4 Inhomogeneous Models 62 3.3.5 Model Comparison 66 3.4 Discussion 68 4 Phenomenological Modifications: Entropic Gravity 73 4.1 Gravity and Thermodynamics 74 4.2 Modifications from Surface Terms 75 4.2.1 Single Fluid 76 4.2.2 Adding a Cosmological Constant 77 4.3 Modifications from Quantum Corrections to the Entropy-area Law 79 4.4 Dark Energy from a Generalized Entropy-area Law 80 4.5 On the Evolution of Perturbations 84 4.6 Discussion 86 5 Standard Matter and Scalar Fields: Disformal Quintessence 89 5.1 Dark Energy from the Disformal Relation 90 5.1.1 Disformal Dark Energy 91 5.1.2 A Variation of the Model 92 5.2 Disformal Quintessence 93 5.2.1 Background Evolution 93 5.2.2 Cosmological Perturbations 97 5.2.3 Observational Constraints 98 5.3 Discussion 101 6 General Relativity and Scalar Forces: Disformal Coupling 103 6.1 A Test Particle in a Disformal Metric 105 6.2 The Zoo of Disformally Related Theories 106 6.2.1 Disformal Curvature: The Conformal Frame 108 vi CONTENTS 6.2.2 Equations in the Einstein Frame 110 6.3 Background Cosmology 113 6.3.1 An Example Model: Disformally Coupled Dark Matter 113 6.4 Cosmological Perturbations 117 6.4.1 Small Scale Limit 118 6.4.2 Structure Formation for Disformally Coupled Matter 118 6.4.3 Viable Scenarios 123 6.5 The Disformal Screening Mechanism 124 6.5.1 Pressure Instability 125 6.5.2 The Scalar Field in Dense, Non-relativistic Environments 125 6.6 Discussion 128 7 Conclusions and Outlook 131 III Appendices 135 A MCMC Analysis 137 B CMBEasy 139 C Equations for Generalized k-essence 141 D Disformal Relations 143 D.1 Disformal Geodesics 144 D.2 General Disformal Coupling Perturbations 144 D.3 Lagrangian Derivatives for Disformal Quintessence 145 List of Tables 147 List of Figures 149 Bibliography 151 vii CONTENTS viii Statement The results presented in this dissertation (Chapters3-6) are based on original work done in collaboration with other researchers during the course of my PhD, from September 2008 to August 2012. The content of these Chapters is based on the released publications [1{6], as well as another ongoing project which is at a mature stage [3]. These references are listed below for convenience. In particular, Chapter3 is based on Reference [1], Chapter4 on References [5,6], Chapter5 is based on Reference [4] and Chapter6 is based on References [2,3]. The introductory Chapters1 and2 are mainly a review. The exposition there has been very influenced by References [7{10], as well the works cited in the text. Although they represent my own vision about some of the topics in which the results are framed, no claim of originality is made about the introductory Chapters. AppendicesA andB describe some of the tools necessary for the analysis. AppendixD contains some lengthy equations that were not necessary to include in the body of the discussion. Miguel Zumalac´arregui P´erez Madrid, October 2012 1. \Tension in the Void: Cosmic Rulers Strain Inhomogeneous Cosmologies" M. Zumalacarregui, J. Garcia-Bellido and P. Ruiz-Lapuente. JCAP 1210, 009 (2012), [arXiv:1201.2790]. 2. \Screening Modifications of Gravity through Disformally Coupled Fields" T. S. Koivisto, D. F. Mota and M. Zumalacarregui. [arXiv:1205.3167]. 3. \DBI Galileons in the Einstein Frame: Local Gravity and Cosmology," M. Zumalacarregui, T. S. Koivisto and D. F. Mota, [arXiv:1210.8016]. 4. \Disformal Scalar Fields and the Dark Sector of the Universe" M. Zumalacarregui, T. S. Koivisto, D. F. Mota and P. Ruiz-Lapuente. JCAP 1005, 038 (2010), [arXiv:1004.2684]. 5. \Constraining Entropic Cosmology" T. S. Koivisto, D. F. Mota and M. Zumalacarregui. JCAP 1102, 027 (2011), [arXiv:1011.2226]. 6. \Modified Entropic Gravity and Cosmology" M. Zumalacarregui. AIP Conf. Proc. 1458, 539 (2011), [arXiv:1202.1281]. ix Statement x Preface You are pooped and demoralized. Why wouldn't you be? Of course it is exhausting, having to reason all the time in a universe which wasn't meant to be reasonable. Kurt Vonnegut1 stronomy and cosmology are arguably the oldest sciences, and perhaps the second oldest professions in history. After many millenia floating in the darkness of mysticism and speculation, cosmology has finally become an em- pirical and predictive discipline. The effort of thousands of scientists, from Aastronomers to theoretical physicists, has carved a Standard Cosmological Model (SCM) that is able to explain a large and increasing set of phenom- ena. The price to pay is the inclusion of three mysterious elements with no conventional explanation: inflation to account for the large scale homogeneity and initial perturbations of the universe, dark matter to enhance the formation of cosmic structure, and a Cosmological Constant to propel the latter stage of accelerated expansion. The Standard Cosmological Model is undoubtedly beautiful. The elegance of the Gen- eral Relativistic geometric description is supplemented by the symmetry of the large scale metric. Despite its simplicity, this scheme seems able to accurately describe the coarse grained evolution of the universe on the largest scales throughout cosmic history. Yet, many ques- tions regarding the nature of the new elements remain unanswered: What is the mechanism behind cosmic inflation and the properties of the dark matter particle(s)? Is cosmic acceler- ation driven by Einstein's Cosmological Constant? If so, why is its value so small compared to particle physics energy scales but still large enough to be observable? If not, how is its value suppressed and what is the true mechanism for the acceleration? The Standard Cosmological Model has been extremely successful in explaining a broad set of observables with just a handful of parameters. The evidence supporting cosmic ac- celeration has grown since the first decisive data from type Ia Supernovae (SNe) pointing towards the existence, and a number of independent observables agree now on the details of this paradigm. Measurements of the Cosmic Microwave Background (CMB) temperature anisotropies support the spatial flatness of the universe. When combined with the determi- 1Breakfast of Champions (1973) xi Preface nation of the local expansion rate, it follows that a smooth component with negative pressure must dominate the cosmic energy budget. Observations of the Large Scale Structure distri- bution confirm this picture. The formation rate of cosmic structures through gravitational collapse bounds the amount of clustering matter to be well below what is necessary for the universe to be spatially flat. The same physics that produces anisotropies in the CMB im- prints a characteristic Baryon Acoustic (BAO) scale in the LSS distribution, which can be measured by galaxy surveys. It provides a standard ruler that tracks the cosmic expansion, further supporting the paradigm of cosmic acceleration. Cosmology has made the promise of new physics. It not only supports its existence, but also provides means to validate or refute the different scenarios. As in a Gold Rush, myriads of alternatives to the Cosmological Constant have been proposed and studied in recent years. These models necessarily modify some sector of the Standard Cosmological model. It is possible to mimic the observed acceleration without the introduction of new exotic elements, by postulating a metric which is inhomogeneous on large scales.
Load more

Recommended publications
  • Inhomogeneous Cosmology with Numerical Relativity
    PHYSICAL REVIEW D 95, 064028 (2017) Inhomogeneous cosmology with numerical relativity Hayley J. Macpherson,* Paul D. Lasky, and Daniel J. Price Monash Centre for Astrophysics and School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia (Received 16 November 2016; published 17 March 2017) We perform three-dimensional numerical relativity simulations of homogeneous and inhomogeneous expanding spacetimes, with a view toward quantifying nonlinear effects from cosmological inhomoge- neities. We demonstrate fourth-order convergence with errors less than one part in 106 in evolving a flat, dust Friedmann-Lemaître-Roberston-Walker spacetime using the Einstein Toolkit within the Cactus framework. We also demonstrate agreement to within one part in 103 between the numerical relativity solution and the linear solution for density, velocity and metric perturbations in the Hubble flow over a factor of ∼350 change in scale factor (redshift). We simulate the growth of linear perturbations into the nonlinear regime, where effects such as gravitational slip and tensor perturbations appear. We therefore show that numerical relativity is a viable tool for investigating nonlinear effects in cosmology. DOI: 10.1103/PhysRevD.95.064028 I. INTRODUCTION spacetimes [41], the propagation and collision of gravita- tional wave perturbations [42,43] and linearized perturba- Modern cosmology relies on the cosmological principle— tions to a homogeneous spacetime [44,45]. More recent that the Universe is sufficiently homogeneous and isotropic work has continued to include symmetries to simplify the on large scales to be described by a Friedmann-Lemaître- numerical calculations, e.g. Refs. [46,47]. Robertson-Walker (FLRW) model. Cosmological N-body Simulations free of these symmetries have only emerged simulations, e.g.
    [Show full text]
  • Spectral Distortion in a Radially Inhomogeneous Cosmology
    Dartmouth College Dartmouth Digital Commons Dartmouth Scholarship Faculty Work 11-5-2013 Spectral Distortion in a Radially Inhomogeneous Cosmology R. R. Caldwell Dartmouth College N. A. Maksimova Dartmouth College Follow this and additional works at: https://digitalcommons.dartmouth.edu/facoa Part of the Cosmology, Relativity, and Gravity Commons Dartmouth Digital Commons Citation Caldwell, R. R. and Maksimova, N. A., "Spectral Distortion in a Radially Inhomogeneous Cosmology" (2013). Dartmouth Scholarship. 1962. https://digitalcommons.dartmouth.edu/facoa/1962 This Article is brought to you for free and open access by the Faculty Work at Dartmouth Digital Commons. It has been accepted for inclusion in Dartmouth Scholarship by an authorized administrator of Dartmouth Digital Commons. For more information, please contact [email protected]. Spectral Distortion in a Radially Inhomogeneous Cosmology R. R. Caldwell1 and N. A. Maksimova1 1Department of Physics & Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 USA (Dated: October 16, 2013) The spectral distortion of the cosmic microwave background blackbody spectrum in a radially inhomogeneous spacetime, designed to exactly reproduce a ΛCDM expansion history along the past light cone, is shown to exceed the upper bound established by COBE-FIRAS by a factor of approximately 3700. This simple observational test helps uncover a slew of pathological features that lie hidden inside the past light cone, including a radially contracting phase at decoupling and, if followed to its logical extreme, a naked singularity at the radially inhomogeneous Big Bang. I. INTRODUCTION Is the Universe playing fair with us? Are the laws of physics and the structure of space-time the same everywhere? It is a fundamental tenet of the Standard Cosmological Model that the answer is yes.
    [Show full text]
  • The Local Value of H0 in an Inhomogeneous Universe
    Prepared for submission to JCAP The local value of H0 in an inhomogeneous universe I. Odderskov,a S. M. Koksbang,a S. Hannestad,a aDepartment of Physics and Astronomy University of Aarhus, Ny Munkegade, Aarhus C, Denmark E-mail: [email protected], [email protected], [email protected] Abstract. The effects of local inhomogeneities on low redshift H0 determinations are studied by estimating the redshift-distance relation of mock sources in N-body simulations. The results are compared to those obtained using the standard approach based on Hubble's law. The comparison shows a clear tendency for the standard approach to yield lower values of H0 than the approach based on the scheme using light rays. The difference is, however, small. More precisely, it is found that the overall effect of inhomogeneities on the determination of H0 is a small increase in the local estimates of about 0:3% compared to the results obtained with Hubble's law, when based on a typical distribution of supernovae in the redshift range 0:01 < z < 0:1. The overall conclusion of the study is a verification of the results that have earlier been obtained by using Hubble's law: The effects of inhomogeneities on local H0 estimates are not significant enough to make it plausible that differences in high- and low-redshift estimates of H0 are due to small inhomogeneities within the setting of standard cosmology. arXiv:1601.07356v2 [astro-ph.CO] 28 Jan 2016 Contents 1 Introduction1 2 Method for computing redshift-distance relations in N-body simulations at low redshift2 3 Mock observations4 3.1 Redshift distribution of sources4 3.2 Observers5 3.3 Lightcone snapshots6 3.4 Summary6 4 Results and discussion7 5 Summary 10 6 Acknowledgments 10 1 Introduction Overall, the ΛCDM model is consistent with observations at a remarkable level considering the model's simplicity compared to the real, inhomogeneous universe.
    [Show full text]
  • Inhomogeneous Cosmological Models and Averaging in Cosmology: Overview
    Home Search Collections Journals About Contact us My IOPscience Inhomogeneous cosmological models and averaging in cosmology: overview This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 Class. Quantum Grav. 28 160301 (http://iopscience.iop.org/0264-9381/28/16/160301) View the table of contents for this issue, or go to the journal homepage for more Download details: IP Address: 194.94.224.254 The article was downloaded on 11/01/2012 at 09:53 Please note that terms and conditions apply. IOP PUBLISHING CLASSICAL AND QUANTUM GRAVITY Class. Quantum Grav. 28 (2011) 160301 (7pp) doi:10.1088/0264-9381/28/16/160301 EDITORIAL Inhomogeneous cosmological models and averaging in cosmology: overview 1. Introduction Cosmological observational data [1]1, when fitted using models based on the assumption of a spatially homogeneous and isotropic Friedmann–Lemaˆıtre–Robertson–Walker (FLRW) model plus small perturbations, are usually interpreted as implying that the spatial geometry is flat, there is currently an accelerated expansion and the majority of the matter in the Universe is dark, non-baryonic and cold, giving rise to the so-called CDM-concordance model (where the dark energy is interpreted as a positive cosmological constant ). The concordance model of cosmology is now operating on a well-established and tightly constrained empirical basis. However, although the concordance CDM model is remarkably successful, there does exist significant tensions between the data and the model [2]. Furthermore, if our Universe is not a perturbation of an exact flat FLRW solution, the conventional data analyses and their interpretation are not necessarily valid [3].
    [Show full text]
  • Observational Cosmology - 30H Course 218.163.109.230 Et Al
    Observational cosmology - 30h course 218.163.109.230 et al. (2004–2014) PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Thu, 31 Oct 2013 03:42:03 UTC Contents Articles Observational cosmology 1 Observations: expansion, nucleosynthesis, CMB 5 Redshift 5 Hubble's law 19 Metric expansion of space 29 Big Bang nucleosynthesis 41 Cosmic microwave background 47 Hot big bang model 58 Friedmann equations 58 Friedmann–Lemaître–Robertson–Walker metric 62 Distance measures (cosmology) 68 Observations: up to 10 Gpc/h 71 Observable universe 71 Structure formation 82 Galaxy formation and evolution 88 Quasar 93 Active galactic nucleus 99 Galaxy filament 106 Phenomenological model: LambdaCDM + MOND 111 Lambda-CDM model 111 Inflation (cosmology) 116 Modified Newtonian dynamics 129 Towards a physical model 137 Shape of the universe 137 Inhomogeneous cosmology 143 Back-reaction 144 References Article Sources and Contributors 145 Image Sources, Licenses and Contributors 148 Article Licenses License 150 Observational cosmology 1 Observational cosmology Observational cosmology is the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors. Early observations The science of physical cosmology as it is practiced today had its subject material defined in the years following the Shapley-Curtis debate when it was determined that the universe had a larger scale than the Milky Way galaxy. This was precipitated by observations that established the size and the dynamics of the cosmos that could be explained by Einstein's General Theory of Relativity.
    [Show full text]
  • Observational Tests of Backreaction with Recent Data
    Journal of Cosmology and Astroparticle Physics Related content - Tension in the void: cosmic rulers strain Observational tests of backreaction with recent inhomogeneous cosmologies Miguel Zumalacárregui, Juan García- data Bellido and Pilar Ruiz-Lapuente - The cosmic microwave background in an inhomogeneous universe To cite this article: Matteo Chiesa et al JCAP12(2014)049 Chris Clarkson and Marco Regis - Testing the void against cosmological data: fitting CMB, BAO, SN and H0 Tirthabir Biswas, Alessio Notari and Wessel Valkenburg View the article online for updates and enhancements. Recent citations - The background Friedmannian Hubble constant in relativistic inhomogeneous cosmology and the age of the Universe Boudewijn F. Roukema et al - Averaged Lemaître–Tolman–Bondi dynamics Eddy G Chirinos Isidro et al - Angular distribution of cosmological parameters as a probe of space-time inhomogeneities C. Sofia Carvalho and Katrine Marques This content was downloaded from IP address 131.169.4.70 on 28/11/2017 at 11:25 ournal of Cosmology and Astroparticle Physics JAn IOP and SISSA journal Observational tests of backreaction with recent data JCAP12(2014)049 Matteo Chiesa,a,b Davide Mainoa and Elisabetta Majerottoc,b aUniversity of Milan, Physics Department, via Giovanni Celoria 16, Milan, Italy bINAF-Osservatorio Astronomico di Brera, via Emilio Bianchi 46, Merate, Italy cDepartamento de F´ısica Te´orica and Instituto de F´ısica Te´orica, Universidad Aut´onoma de Madrid IFT-UAM/CSIC, 28049 Cantoblanco, Madrid, Spain E-mail: [email protected], [email protected], [email protected] Received June 3, 2014 Revised November 7, 2014 Accepted November 28, 2014 Published December 22, 2014 Abstract.
    [Show full text]
  • Inhomogeneous Structure Formation May Alleviate Need for Accelerating Universe Johan Hansson* and Jesper Lindkvist
    The Open Astronomy Journal, 2010, 3, 145-149 145 Open Access Inhomogeneous Structure Formation May Alleviate Need for Accelerating Universe Johan Hansson* and Jesper Lindkvist Department of Physics, Luleå University of Technology, SE-971 87 Luleå, Sweden Abstract: When taking the real, inhomogeneous and anisotropic matter distribution in the semi-local universe into account, there may be no need to postulate an accelerating expansion of the universe despite recent type Ia supernova data. Local curvatures must be integrated (over all space) to obtain the global curvature of the universe, which seems to be very close to zero from cosmic microwave background data. As gravitational structure formation creates bound regions of positive curvature, the regions in between become negatively curved in order to comply with a vanishing global curvature. The actual dynamics of the universe is altered due to the self-induced inhomogeneities, again more prominently so as structure formation progresses. Furthermore, this negative curvature will increase as a function of time as structure formation proceeds, which mimics the effect of “dark energy” with negative pressure. Hence, the “acceleration” may be merely a mirage. We make a qualitative and semi-quantitative analysis, for pedagogical reasons using newtonian gravity corrected for special relativistic effects (which works surprisingly well) to corroborate and illustrate/visualize these statements. This article may be seen as an attempt to communicate to a larger number of people the necessity of starting to take seriously the real, observed inhomogeneous distribution and the nonlinearities of nonperturbative general relativity, and their impact on the dynamics and behavior of the cosmos instead of allowing an oversimplified cosmological model to generate a consensus world-view of a cosmos allegedly dominated by mysterious dark energy.
    [Show full text]
  • Consistent Young Earth Relativistic Cosmology
    The Proceedings of the International Conference on Creationism Volume 8 Print Reference: Pages 14-35 Article 23 2018 Consistent Young Earth Relativistic Cosmology Phillip W. Dennis Unaffiliated Follow this and additional works at: https://digitalcommons.cedarville.edu/icc_proceedings Part of the Cosmology, Relativity, and Gravity Commons DigitalCommons@Cedarville provides a publication platform for fully open access journals, which means that all articles are available on the Internet to all users immediately upon publication. However, the opinions and sentiments expressed by the authors of articles published in our journals do not necessarily indicate the endorsement or reflect the views of DigitalCommons@Cedarville, the Centennial Library, or Cedarville University and its employees. The authors are solely responsible for the content of their work. Please address questions to [email protected]. Browse the contents of this volume of The Proceedings of the International Conference on Creationism. Recommended Citation Dennis, P.W. 2018. Consistent young earth relativistic cosmology. In Proceedings of the Eighth International Conference on Creationism, ed. J.H. Whitmore, pp. 14–35. Pittsburgh, Pennsylvania: Creation Science Fellowship. Dennis, P.W. 2018. Consistent young earth relativistic cosmology. In Proceedings of the Eighth International Conference on Creationism, ed. J.H. Whitmore, pp. 14–35. Pittsburgh, Pennsylvania: Creation Science Fellowship. CONSISTENT YOUNG EARTH RELATIVISTIC COSMOLOGY Phillip W. Dennis, 1655 Campbell Avenue,
    [Show full text]
  • CONTENTS the Marcel Grossmann Meetings
    July 21, 2008 11:37 WSPC - Proceedings Trim Size: 9.75in x 6.5in contents 21 CONTENTS The Marcel Grossmann Meetings | Publications in this Series and Sponsors . v Organizing Committees . vii Marcel Grossmann Awards . ix Preface . xiii Inaugural Address . xix Marcel Grossmann Award Essay . xxi PART A PLENARY AND REVIEW TALKS A Brief History of X-Ray Astronomy in Germany Truemper, Joachim E. 3 On the Discovery of the Kerr metric Kerr, Roy Patrick . 9 Chaos and Symmetry in String Cosmology Damour, Thibault . 39 Hidden Symmetries, Cosmological Singularities and the E10=K(E10) Sigma Model Kleinschmidt, Axel; Nicolai, Herman . 49 The Nature of Generic Cosmological Singularities Uggla, Claes . 73 QCD and String Theory Klebanov, Igor R. 90 The Cosmic String Inverse Problem Polchinski, Joseph . 105 Loop Quantum Gravity: Four Recent Advances and a Dozen Frequently Asked Questions Ashtekar, Abhay . 126 String Theory Landscape and the Standard Model of Particle Physics Lust,¨ Dieter . 148 The Status of the Virgo Gravitational Wave Detector Bizouard, Marie-Anne; for the Virgo collaboration . 177 July 21, 2008 11:37 WSPC - Proceedings Trim Size: 9.75in x 6.5in contents 22 Analytical Modeling of Binary Black Holes Coalescence Buonanno, Alessandra . 197 Binary Pulsars and General Relativistic Effects Kramer, Michael . 225 Space Astronometry and Relativity Mignard, Fran¸cois; Klioner, Sergei A. 245 Neutrino Astronomy 2006 Halzen, Francis . 272 Dark Matter and Sterile Neutrinos Biermann, Peter L.; Munyaneza, Faustin . 291 Supercomputer Simulations of the Joint Formation and Evolution of Galaxies and Quasars Springel, Volker . 309 CMB Observations: From BOOMERanG to Planck : : : and Beyond De Bernardis, Paolo . 326 The Origins and the Early Evolution of Quasars and Supermassive Black Holes Djorgovski, S.
    [Show full text]
  • Inhomogeneous Pre-Big Bang String Cosmology
    March 21 1997 CERN-TH/97-42 Inhomogeneous Pre-Big Bang String Cosmology G. Veneziano Theory Division, CERN, CH-1211 Geneva 23, Switzerland Abstract An inhomogeneous version of Pre–Big Bang cosmology emerges, within string theory, from quite generic initial conditions, provided they lie deeply inside the weak-coupling, low- curvature regime. Large-scale homogeneity, flatness, and isotropy appear naturally as late- time outcomes of such an evolution. CERN-TH/97-42 March 1997 1 Introduction Superstring theory, a supposedly consistent and unified quantum theory of all interactions, suggests, through its peculiar duality symmetries [1], an attractive alternative to standard inflationary cosmology, the so-called Pre- Big Bang (PBB) scenario [2] [3] [4]. The basic postulate of PBB cosmology is that the Universe started its evolution from a very perturbative initial state, i.e. from very weak coupling and very small curvatures (in appropriate units, see below). If initial homogeneity is also assumed, this leads automatically to a super-inflationary epoch during which the accelerated expansion of the Universe is driven by the accelerated growth of the effective (gauge and gravity) coupling, i.e. of the dilaton. This result looks surprising, at first sight, since the equation of state of the dilaton is not of the kind that one usually associates with inflation. Indeed, inflation only occurs if the geometry is looked at in the so-called String(S)-frame, the one appearing in the Nambu- Goto-Polyakov action, while in the Einstein(E)-frame one rather observes an accelerated contraction. The point here is that, precisely at weak coupling and small curvatures, fun- damental strings keep their characteristic size constant and sweep geodesic surfaces with respect to the S-frame metric [5] [6].
    [Show full text]
  • Inhomogeneous Cosmology: an Answer to the Dark Matter and Dark Energy Problems?
    Inhomogeneous cosmology : an answer to the Dark Matter and Dark Energy problems? Alexandre Alles To cite this version: Alexandre Alles. Inhomogeneous cosmology : an answer to the Dark Matter and Dark Energy problems?. Astrophysics [astro-ph]. Université Claude Bernard - Lyon I, 2014. English. NNT : 2014LYO10165. tel-01266465 HAL Id: tel-01266465 https://tel.archives-ouvertes.fr/tel-01266465 Submitted on 2 Feb 2016 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Num´ero d’ordre : 165 - 2014 Ann´ee 2014 THESE` DE L’UNIVERSITEDELYON´ D´elivr´ee par L’UNIVERSITE´ CLAUDE BERNARD LYON 1 ECOLE´ DOCTORALE DE PHYSIQUE ET ASTROPHYSIQUE DE LYON (PHAST, ED52) pour l’obtention du Diplomeˆ de Doctorat (arrˆet´edu7aoˆut 2006) soutenue publiquement le 22 Septembre 2014 par M. Alexandre Alles Titre : Inhomogeneous cosmology, an answer to the Dark Matter and Dark Energy problems? Jury : Alexandre Arbey, MCF. Examinateur Thomas Buchert,Pr. Directeur Aldo Deandrea,Pr. Examinateur Boudewijn F. Roukema,Pr. Rapporteur et Examinateur Pierre Salati,Pr. Pr´esident David L. Wiltshire,Pr. Rapporteur – Centre de Recherche Astrophysique de Lyon (CRAL - UMR 5574) – – Universite´ Claude Bernard Lyon 1 (UCBL) – – Ecole Doctorale de Physique et Astrophysique de Lyon (ED PHAST 52) – Inhomogeneous cosmology: an answer to the Dark Matter and Dark Energy problems? Author: Alexandre Alles September 21, 2014 Supervisor: Pr.
    [Show full text]
  • Solving the Horizon Problem with a Delayed Big-Bang Singularity
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server SOLVING THE HORIZON PROBLEM WITH A DELAYED BIG-BANG SINGULARITY Marie-No¨elle CEL´ ERIER´ D´epartement d'Astrophysique Relativiste et de Cosmologie Observatoire de Paris{Meudon 5 Place Jules Janssen 92195 Meudon C´edex FRANCE The hot Big-Bang standard model for the evolution of the universe, despite strong successes, lets unresolved a number of problems. One of its main drawbacks, known as the horizon problem, was until now thought to be only solvable by an inflationary scenario. Here is proposed a class of inhomogeneous models of universe, getting rid of some of the worst drawbacks of standard cosmology. The horizon problem is solved by means of an initial singularity of “delayed” type and without need for any inflationary phase. The flatness and cosmological constant problems disappear. In this work, completed in collaboration with Jean Schneider 1,inthe framework of General Relativity, the Cosmological Principle is discarded to solve the horizon, flatness and cosmological constant problems, without any inflationary assumption, while keeping the successfull predictions of the stan- dard model. 1 The Cosmological Principle The standard justification of this principle rests on two arguments. One, observation-based, is the quasi-isotropy of the CMBR around us. The sec- ond, philosophical, asserts that our location in the universe is not special, and what we observe around us must be thus observed the same from everywhere. The standard conclusion is that the matter distribution of the universe is ho- mogeneous. One can, however, refuse the copernician argument.
    [Show full text]