DOCSLIB.ORG

Cosmological Inflation, Dark Matter and Dark Energy

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cosmological Inflation, Dark Matter and Dark Energy Cosmological Inflation, Dark Matter and Dark Energy Edited by Kazuharu Bamba Printed Edition of the Special Issue Published in Symmetry www.mdpi.com/journal/symmetry Cosmological Inflation, Dark Matter and Dark Energy Cosmological Inflation, Dark Matter and Dark Energy Special Issue Editor Kazuharu Bamba MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade Special Issue Editor Kazuharu Bamba Fukushima University Japan Editorial Office MDPI St. Alban-Anlage 66 4052 Basel, Switzerland This is a reprint of articles from the Special Issue published online in the open access journal Symmetry (ISSN 2073-8994) from 2018 to 2019 (available at: https://www.mdpi.com/journal/symmetry/ special issues/Cosmological Inflation Dark Matter Dark Energy). For citation purposes, cite each article independently as indicated on the article page online and as indicated below: LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. Journal Name Year, Article Number, Page Range. ISBN 978-3-03921-764-9 (Pbk) ISBN 978-3-03921-765-6 (PDF) c 2019 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. The book as a whole is distributed by MDPI under the terms and conditions of the Creative Commons license CC BY-NC-ND. Contents About the Special Issue Editor ...................................... vii Preface to ”Cosmological Inflation, Dark Matter and Dark Energy” ................ ix Emma Kun, Zolt´an Keresztes, Das Saurya, L´aszl´o A.´ Gergely Dark Matter as a Non-Relativistic Bose–Einstein Condensate with Massive Gravitons Reprinted from: Symmetry 2018, 10, 520, doi:10.3390/sym10100520 ................. 1 Vitaly Beylin, Maxim Yu. Khlopov, Vladimir Kuksa and Nikolay Volchanskiy Hadronic and Hadron-Like Physics of Dark Matter Reprinted from: Symmetry 2019, 11, 587, doi:10.3390/sym11040587 ................. 14 M. Sharif, Syed Asif Ali Shah and Kazuharu Bamba New Holographic Dark Energy Model in Brans-Dicke Theory Reprinted from: Symmetry 2018, 10, 153, doi:10.3390/sym10050153 ................. 60 Ivan de Martino Decaying Dark Energy in Light of the Latest Cosmological Dataset Reprinted from: Symmetry 2018, 10, 372, doi:10.3390/sym10090372 ................. 70 Alexander B. Balakin and Alexei S. Ilin Dark Energy and Dark Matter Interaction: Kernels of Volterra Type and Coincidence Problem Reprinted from: Symmetry 2018, 10, 411, doi:10.3390/sym10090411 ................. 85 Abdul Jawad, Kazuharu Bamba, M. Younas, Saba Qummer and Shamaila Rani Tsallis,Renyi´ and Sharma-Mittal Holographic Dark Energy Models inLoop Quantum Cosmology Reprinted from: Symmetry 2018, 10, 635, doi:10.3390/sym10110635 .................101 Irina Dymnikova and Anna Dobosz Spacetime Symmetry and LemaˆıTre Class Dark Energy Models Reprinted from: Symmetry 2019, 11, 90, doi:10.3390/sym11010090 ..................116 Shamaila Rani, AbdulJawad, Kazuharu Bamba and Irfan Ullah Malik Cosmological Consequences of New Dark Energy Models in Einstein-Aether Gravity Reprinted from: Symmetry 2019, 11, 509, doi:10.3390/sym11040509 .................134 Abdul Jawad, Shamaila Rani, Sidra Saleem, Kazuharu Bamba and Riffat Jabeen Cosmological Consequences of a Parametrized Equation of State Reprinted from: Symmetry 2019, 11, 1009, doi:10.3390/sym11081009 .................159 Taisaku Mori and Shin’ichi Nojiri Topological Gravity Motivated by Renormalization Group Reprinted from: Symmetry 2018, 10, 396, doi:10.3390/sym10090396 .................176 Orchidea Maria Lecian Alternative Uses for Quantum Systems and Devices Reprinted from: Symmetry 2019, 11, 462, doi:10.3390/sym11040462 .................188 Bence Racsk´o, L´aszl´o A.´ Gergely The Lanczos Equation on Light-Like Hypersurfaces in a Cosmologically Viable Class of Kinetic Gravity Braiding Theories Reprinted from: Symmetry 2019, 11, 616, doi:10.3390/sym11050616 .................205 v Riasat Ali, Kazuharu Bamba, Syed Asif Ali Shah Effect of Quantum Gravity on the Stability of Black Holes Reprinted from: Symmetry 2019, 11, 631, doi:10.3390/sym11050631 .................213 vi About the Special Issue Editor Kazuharu Bamba received his Ph.D. from Osaka University in 2006 and served as JSPS Postdoctoral Research Fellow at Yukawa Institute for Theoretical Physics (YITP), Kyoto University. He also worked at Kinki University as a Postdoctoral Research Fellow and then he moved to National Tsing Hua University, Taiwan, in 2008. In 2010, he became Assistant Professor at Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, and worked on dark energy problems and modified gravity theories. In 2014, he was appointed Lecturer at Ochanomizu University. In 2015, he began as Associate Professor at Fukushima University in Japan, where he teaches physics and cosmology. He has published more than 110 papers in international refereed journals. Since 2014, he has been the Associate Editor-in-Chief of Universe (MDPI), and also an Editor of Entropy since 2014 and Symmetry since 2018. vii Preface to ”Cosmological Inflation, Dark Matter and Dark Energy” Based on recent cosmological observations, such as type Ia supernovae, cosmic microwave background (CMB) radiation large-scale structure, baryon acoustic oscillations (BAO), and weak lensing, the universe has experienced an accelerated phase of its expansion, not only regarding the early universe but also in present times. The former is called “inflation” and the latter is called “the late-time cosmic acceleration”. It is also well known that the three energy components of the universe are dark energy (about 68%), dark matter (about 27%), and baryon (about 5%). A number of studies have been executed for the origins of the field to realize inflation, dark matter, and dark energy. The future detection of primordial gravitational waves is strongly expected in order to know the energy scale of the inflationary phase. Moreover, there are two possibilities for the origin of dark matter, namely, new particles in particle theory models beyond the standard model and astrophysical objects. Furthermore, two representative studies have been proposed for the true character of dark energy. One is the introduction of some unknown matter called dark energy with the negative pressure in the framework of general relativity. The other is the modification of gravity at large scales, leading to the so-called geometrical dark energy. The main aim of this book is to understand various cosmological aspects, including the origins of inflation, dark matter, and dark energy. It is one of the most significant and fundamental issues in modern physics and cosmology. In addition to phenomenological approaches, more fundamental studies are considered from higher-dimensional theories of gravity, quantum gravity, and quantum cosmology, physics in the early universe, quantum field theories, and gauge field theories in curved spacetime as well as strings, branes, and the holographic principle. This book consists of the 13 peer-reviewed articles published in the Special Issue “Cosmological Inflation, Dark Matter and Dark Energy” in Symmetry. As Guest Editor of this Special Issue, I have invited the authors to write original articles to the Issue and rearranged the contents for this book. The organization of this book is as follows. The first part (2 articles) concerns the origin and nature of dark matter. The second (7 articles) details the mechanisms for the cosmic accelerations of dark energy as well as inflation. The third (4 articles) covers gravity theories and their quantum aspects. I would like to sincerely acknowledge MDPI and am greatly appreciative of the Managing Editor, Ms. Dalia Su, for her very kind support and warm assistance during this project. Moreover, I am highly grateful to the Editor-in-Chief Professor Dr. Sergei D. Odintsov for giving me the chance to serve as Guest Editor of this Special Issue. Furthermore, since this is my first memorial editorial book, I would like to express my sincere gratitude to my supervisors Professor Dr. Jun’ichi Yokoyama, Professor Dr. Misao Sasaki, Professor Dr. Motohiko Yoshimura, Professor Dr. Fumio Takahara; my professors Professor Dr. Shin’ichi Nojiri, Professor Dr. Akio Sugamoto, Professor Dr. Chao-Qiang Geng, Professor Dr. Nobuyoshi Ohta; my important collaborators on the topics in this book, Professor Dr. Salvatore Capozziello, Professor Dr. Emmanuel N. Saridakis, Professor Dr. Shinji Tsujikawa; as well as to all of my collaborators. I would also like to thank all the authors for the submission of their articles to this Special Issue of Symmetry. Kazuharu Bamba Special Issue Editor ix S symmetry S Article Dark Matter as a Non-Relativistic Bose–Einstein Condensate with Massive Gravitons Emma Kun 1, Zoltán Keresztes 1,*, Saurya Das 2 and László Á. Gergely 1 1 Institute of Physics, University of Szeged, Dóm tér 9, H-6720 Szeged, Hungary; [email protected] (E.K.); [email protected] (L.Á.G.) 2 Theoretical Physics Group and Quantum Alberta, Department of Physics and Astronomy, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada; [email protected] * Correspondence: [email protected] Received: 15 September 2018; Accepted: 15 October 2018; Published: 17 October 2018 Abstract: We confront a non-relativistic Bose–Einstein Condensate (BEC) model of light
Load more

Recommended publications
  • Fuzzy Cold Dark Matter: the Wave Properties of Ultralight Particles
    VOLUME 85, NUMBER 6 PHYSICAL REVIEW LETTERS 7AUGUST 2000 Fuzzy Cold Dark Matter: The Wave Properties of Ultralight Particles Wayne Hu, Rennan Barkana, and Andrei Gruzinov Institute for Advanced Study, Princeton, New Jersey 08540 (Received 27 March 2000) Cold dark matter (CDM) models predict small-scale structure in excess of observations of the cores and abundance of dwarf galaxies. These problems might be solved, and the virtues of CDM models retained, even without postulating ad hoc dark matter particle or field interactions, if the dark matter is composed of ultralight scalar particles ͑m ϳ 10222 eV͒, initially in a (cold) Bose-Einstein condensate, similar to axion dark matter models. The wave properties of the dark matter stabilize gravitational collapse, providing halo cores and sharply suppressing small-scale linear power. PACS numbers: 95.35.+d, 98.80.Cq Introduction.—Recently, the small-scale shortcomings particle horizon, one can employ a Newtonian approxi- of the otherwise widely successful cold dark matter (CDM) mation to the gravitational interaction embedded in the models for structure formation have received much atten- covariant derivatives of the field equation and a nonrela- tion (see [1–4] and references therein). CDM models pre- tivistic approximation to the dispersion relation. It is then dict cuspy dark matter halo profiles and an abundance of convenient to define the wave function c ϵ Aeia, out of low mass halos not seen in the rotation curves and local the amplitude and phase of the field f ෇ A cos͑mt 2a͒, population of dwarf galaxies, respectively. Although the which obeys µ ∂ µ ∂ significance of the discrepancies is still disputed and so- ᠨ 3 a 1 2 lutions involving astrophysical processes in the baryonic i ≠t 1 c ෇ 2 = 1 mC c , (2) gas may still be possible (e.g., [5]), recent attention has fo- 2 a 2m cused mostly on solutions involving the dark matter sector.
    [Show full text]
  • Dark Energy and Dark Matter As Inertial Effects Introduction
    Dark Energy and Dark Matter as Inertial Effects Serkan Zorba Department of Physics and Astronomy, Whittier College 13406 Philadelphia Street, Whittier, CA 90608 [email protected] ABSTRACT A disk-shaped universe (encompassing the observable universe) rotating globally with an angular speed equal to the Hubble constant is postulated. It is shown that dark energy and dark matter are cosmic inertial effects resulting from such a cosmic rotation, corresponding to centrifugal (dark energy), and a combination of centrifugal and the Coriolis forces (dark matter), respectively. The physics and the cosmological and galactic parameters obtained from the model closely match those attributed to dark energy and dark matter in the standard Λ-CDM model. 20 Oct 2012 Oct 20 ph] - PACS: 95.36.+x, 95.35.+d, 98.80.-k, 04.20.Cv [physics.gen Introduction The two most outstanding unsolved problems of modern cosmology today are the problems of dark energy and dark matter. Together these two problems imply that about a whopping 96% of the energy content of the universe is simply unaccounted for within the reigning paradigm of modern cosmology. arXiv:1210.3021 The dark energy problem has been around only for about two decades, while the dark matter problem has gone unsolved for about 90 years. Various ideas have been put forward, including some fantastic ones such as the presence of ghostly fields and particles. Some ideas even suggest the breakdown of the standard Newton-Einstein gravity for the relevant scales. Although some progress has been made, particularly in the area of dark matter with the nonstandard gravity theories, the problems still stand unresolved.
    [Show full text]
  • Galaxy Formation with Ultralight Bosonic Dark Matter
    GALAXY FORMATION WITH ULTRALIGHT BOSONIC DARK MATTER Dissertation zur Erlangung des mathematisch-naturwissenschaftlichen Doktorgrades "Doctor rerum naturalium" der Georg-August-Universit¨atG¨ottingen im Promotionsstudiengang Physik der Georg-August University School of Science (GAUSS) vorgelegt von Jan Veltmaat aus Bietigheim-Bissingen G¨ottingen,2019 Betreuungsausschuss Prof. Dr. Jens Niemeyer, Institut f¨urAstrophysik, Universit¨atG¨ottingen Prof. Dr. Steffen Schumann, Institut f¨urTheoretische Physik, Universit¨atG¨ottingen Mitglieder der Pr¨ufungskommission Referent: Prof. Dr. Jens Niemeyer, Institut f¨urAstrophysik, Universit¨atG¨ottingen Korreferent: Prof. Dr. David Marsh, Institut f¨urAstrophysik, Universit¨atG¨ottingen Weitere Mitglieder der Pr¨ufungskommission: Prof. Dr. Fabian Heidrich-Meisner, Institut f¨urTheoretische Physik, Universit¨atG¨ottingen Prof. Dr. Wolfram Kollatschny, Institut f¨urAstrophysik, Universit¨atG¨ottingen Prof. Dr. Steffen Schumann, Institut f¨urTheoretische Physik, Universit¨atG¨ottingen Dr. Michael Wilczek, Max-Planck-Institut f¨urDynamik und Selbstorganisation, G¨ottingen Tag der m¨undlichen Pr¨ufung:12.12.2019 Abstract Ultralight bosonic particles forming a coherent state are dark matter candidates with distinctive wave-like behaviour on the scale of dwarf galaxies and below. In this thesis, a new simulation technique for ul- tralight bosonic dark matter, also called fuzzy dark matter, is devel- oped and applied in zoom-in simulations of dwarf galaxy halos. When gas and star formation are not included in the simulations, it is found that halos contain solitonic cores in their centers reproducing previous results in the literature. The cores exhibit strong quasi-normal oscil- lations, which are possibly testable by observations. The results are inconclusive regarding the long-term evolution of the core mass.
    [Show full text]
  • Baryogenesis in a CP Invariant Theory That Utilizes the Stochastic Movement of Light fields During Inflation
    Baryogenesis in a CP invariant theory Anson Hook School of Natural Sciences Institute for Advanced Study Princeton, NJ 08540 June 12, 2018 Abstract We consider baryogenesis in a model which has a CP invariant Lagrangian, CP invariant initial conditions and does not spontaneously break CP at any of the minima. We utilize the fact that tunneling processes between CP invariant minima can break CP to implement baryogenesis. CP invariance requires the presence of two tunneling processes with opposite CP breaking phases and equal probability of occurring. In order for the entire visible universe to see the same CP violating phase, we consider a model where the field doing the tunneling is the inflaton. arXiv:1508.05094v1 [hep-ph] 20 Aug 2015 1 1 Introduction The visible universe contains more matter than anti-matter [1]. The guiding principles for gener- ating this asymmetry have been Sakharov’s three conditions [2]. These three conditions are C/CP violation • Baryon number violation • Out of thermal equilibrium • Over the years, counter examples have been found for Sakharov’s conditions. One can avoid the need for number violating interactions in theories where the negative B L number is stored − in a sector decoupled from the standard model, e.g. in right handed neutrinos as in Dirac lep- togenesis [3, 4] or in dark matter [5]. The out of equilibrium condition can be avoided if one uses spontaneous baryogenesis [6], where a chemical potential is used to create a non-zero baryon number in thermal equilibrium. However, these models still require a C/CP violating phase or coupling in the Lagrangian.
    [Show full text]
  • Physical Cosmology," Organized by a Committee Chaired by David N
    Proc. Natl. Acad. Sci. USA Vol. 90, p. 4765, June 1993 Colloquium Paper This paper serves as an introduction to the following papers, which were presented at a colloquium entitled "Physical Cosmology," organized by a committee chaired by David N. Schramm, held March 27 and 28, 1992, at the National Academy of Sciences, Irvine, CA. Physical cosmology DAVID N. SCHRAMM Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 The Colloquium on Physical Cosmology was attended by 180 much notoriety. The recent report by COBE of a small cosmologists and science writers representing a wide range of primordial anisotropy has certainly brought wide recognition scientific disciplines. The purpose of the colloquium was to to the nature of the problems. The interrelationship of address the timely questions that have been raised in recent structure formation scenarios with the established parts of years on the interdisciplinary topic of physical cosmology by the cosmological framework, as well as the plethora of new bringing together experts of the various scientific subfields observations and experiments, has made it timely for a that deal with cosmology. high-level international scientific colloquium on the subject. Cosmology has entered a "golden age" in which there is a The papers presented in this issue give a wonderful mul- tifaceted view of the current state of modem physical cos- close interplay between theory and observation-experimen- mology. Although the actual COBE anisotropy announce- tation. Pioneering early contributions by Hubble are not ment was made after the meeting reported here, the following negated but are amplified by this current, unprecedented high papers were updated to include the new COBE data.
    [Show full text]
  • Dark Matter and the Early Universe: a Review Arxiv:2104.11488V1 [Hep-Ph
    Dark matter and the early Universe: a review A. Arbey and F. Mahmoudi Univ Lyon, Univ Claude Bernard Lyon 1, CNRS/IN2P3, Institut de Physique des 2 Infinis de Lyon, UMR 5822, 69622 Villeurbanne, France Theoretical Physics Department, CERN, CH-1211 Geneva 23, Switzerland Institut Universitaire de France, 103 boulevard Saint-Michel, 75005 Paris, France Abstract Dark matter represents currently an outstanding problem in both cosmology and particle physics. In this review we discuss the possible explanations for dark matter and the experimental observables which can eventually lead to the discovery of dark matter and its nature, and demonstrate the close interplay between the cosmological properties of the early Universe and the observables used to constrain dark matter models in the context of new physics beyond the Standard Model. arXiv:2104.11488v1 [hep-ph] 23 Apr 2021 1 Contents 1 Introduction 3 2 Standard Cosmological Model 3 2.1 Friedmann-Lema^ıtre-Robertson-Walker model . 4 2.2 A quick story of the Universe . 5 2.3 Big-Bang nucleosynthesis . 8 3 Dark matter(s) 9 3.1 Observational evidences . 9 3.1.1 Galaxies . 9 3.1.2 Galaxy clusters . 10 3.1.3 Large and cosmological scales . 12 3.2 Generic types of dark matter . 14 4 Beyond the standard cosmological model 16 4.1 Dark energy . 17 4.2 Inflation and reheating . 19 4.3 Other models . 20 4.4 Phase transitions . 21 5 Dark matter in particle physics 21 5.1 Dark matter and new physics . 22 5.1.1 Thermal relics . 22 5.1.2 Non-thermal relics .
    [Show full text]
  • Adrien Christian René THOB
    THE RELATIONSHIP BETWEEN THE MORPHOLOGY AND KINEMATICS OF GALAXIES AND ITS DEPENDENCE ON DARK MATTER HALO STRUCTURE IN SIMULATED GALAXIES Adrien Christian René THOB A thesis submitted in partial fulfilment of the requirements of Liverpool John Moores University for the degree of Doctor of Philosophy. 26 April 2019 To my grand-parents, René Roumeaux, Christian Thob, Yvette Roumeaux (née Bajaud) and Anne-Marie Thob (née Léglise). ii Abstract Galaxies are among nature’s most majestic and diverse structures. They can play host to as few as several thousands of stars, or as many as hundreds of billions. They exhibit a broad range of shapes, sizes, colours, and they can inhabit vastly differing cosmic environments. The physics of galaxy formation is highly non-linear and in- volves a variety of physical mechanisms, precluding the development of entirely an- alytic descriptions, thus requiring that theoretical ideas concerning the origin of this diversity are tested via the confrontation of numerical models (or “simulations”) with observational measurements. The EAGLE project (which stands for Evolution and Assembly of GaLaxies and their Environments) is a state-of-the-art suite of such cos- mological hydrodynamical simulations of the Universe. EAGLE is unique in that the ill-understood efficiencies of feedback mechanisms implemented in the model were calibrated to ensure that the observed stellar masses and sizes of present-day galaxies were reproduced. We investigate the connection between the morphology and internal 9:5 kinematics of the stellar component of central galaxies with mass M? > 10 M in the EAGLE simulations. We compare several kinematic diagnostics commonly used to describe simulated galaxies, and find good consistency between them.
    [Show full text]
  • Eternal Inflation and Its Implications
    IOP PUBLISHING JOURNAL OF PHYSICS A: MATHEMATICAL AND THEORETICAL J. Phys. A: Math. Theor. 40 (2007) 6811–6826 doi:10.1088/1751-8113/40/25/S25 Eternal inflation and its implications Alan H Guth Center for Theoretical Physics, Laboratory for Nuclear Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA E-mail: [email protected] Received 8 February 2006 Published 6 June 2007 Online at stacks.iop.org/JPhysA/40/6811 Abstract Isummarizetheargumentsthatstronglysuggestthatouruniverseisthe product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are described. Although the infinity of pocket universes produced by eternal inflation are unobservable, it is argued that eternal inflation has real consequences in terms of the way that predictions are extracted from theoretical models. The ambiguities in defining probabilities in eternally inflating spacetimes are reviewed, with emphasis on the youngness paradox that results from a synchronous gauge regularization technique. Although inflation is generically eternal into the future, it is not eternal into the past: it can be proven under reasonable assumptions that the inflating region must be incomplete in past directions, so some physics other than inflation is needed to describe the past boundary of the inflating region. PACS numbers: 98.80.cQ, 98.80.Bp, 98.80.Es 1. Introduction: the successes of inflation Since the proposal of the inflationary model some 25 years ago [1–4], inflation has been remarkably successful in explaining many important qualitative and quantitative properties of the universe. In this paper, I will summarize the key successes, and then discuss a number of issues associated with the eternal nature of inflation.
    [Show full text]
  • Particle Dark Matter an Introduction Into Evidence, Models, and Direct Searches
    Particle Dark Matter An Introduction into Evidence, Models, and Direct Searches Lecture for ESIPAP 2016 European School of Instrumentation in Particle & Astroparticle Physics Archamps Technopole XENON1T January 25th, 2016 Uwe Oberlack Institute of Physics & PRISMA Cluster of Excellence Johannes Gutenberg University Mainz http://xenon.physik.uni-mainz.de Outline ● Evidence for Dark Matter: ▸ The Problem of Missing Mass ▸ In galaxies ▸ In galaxy clusters ▸ In the universe as a whole ● DM Candidates: ▸ The DM particle zoo ▸ WIMPs ● DM Direct Searches: ▸ Detection principle, physics inputs ▸ Example experiments & results ▸ Outlook Uwe Oberlack ESIPAP 2016 2 Types of Evidences for Dark Matter ● Kinematic studies use luminous astrophysical objects to probe the gravitational potential of a massive environment, e.g.: ▸ Stars or gas clouds probing the gravitational potential of galaxies ▸ Galaxies or intergalactic gas probing the gravitational potential of galaxy clusters ● Gravitational lensing is an independent way to measure the total mass (profle) of a foreground object using the light of background sources (galaxies, active galactic nuclei). ● Comparison of mass profles with observed luminosity profles lead to a problem of missing mass, usually interpreted as evidence for Dark Matter. ● Measuring the geometry (curvature) of the universe, indicates a ”fat” universe with close to critical density. Comparison with luminous mass: → a major accounting problem! Including observations of the expansion history lead to the Standard Model of Cosmology: accounting defcit solved by ~68% Dark Energy, ~27% Dark Matter and <5% “regular” (baryonic) matter. ● Other lines of evidence probe properties of matter under the infuence of gravity: ▸ the equation of state of oscillating matter as observed through fuctuations of the Cosmic Microwave Background (acoustic peaks).
    [Show full text]
  • A Correspondence Between Strings in the Hagedorn Phase and Asymptotically De Sitter Space
    A correspondence between strings in the Hagedorn phase and asymptotically de Sitter space Ram Brustein(1), A.J.M. Medved(2;3) (1) Department of Physics, Ben-Gurion University, Beer-Sheva 84105, Israel (2) Department of Physics & Electronics, Rhodes University, Grahamstown 6140, South Africa (3) National Institute for Theoretical Physics (NITheP), Western Cape 7602, South Africa [email protected], [email protected] Abstract A correspondence between closed strings in their high-temperature Hage- dorn phase and asymptotically de Sitter (dS) space is established. We identify a thermal, conformal field theory (CFT) whose partition function is, on the one hand, equal to the partition function of closed, interacting, fundamental strings in their Hagedorn phase yet is, on the other hand, also equal to the Hartle-Hawking (HH) wavefunction of an asymptotically dS Universe. The Lagrangian of the CFT is a functional of a single scalar field, the condensate of a thermal scalar, which is proportional to the entropy density of the strings. The correspondence has some aspects in common with the anti-de Sitter/CFT correspondence, as well as with some of its proposed analytic continuations to a dS/CFT correspondence, but it also has some important conceptual and technical differences. The equilibrium state of the CFT is one of maximal pres- sure and entropy, and it is at a temperature that is above but parametrically close to the Hagedorn temperature. The CFT is valid beyond the regime of semiclassical gravity and thus defines the initial quantum state of the dS Uni- verse in a way that replaces and supersedes the HH wavefunction.
    [Show full text]
  • Dark Energy and Dark Matter
    Dark Energy and Dark Matter Jeevan Regmi Department of Physics, Prithvi Narayan Campus, Pokhara [email protected] Abstract: The new discoveries and evidences in the field of astrophysics have explored new area of discussion each day. It provides an inspiration for the search of new laws and symmetries in nature. One of the interesting issues of the decade is the accelerating universe. Though much is known about universe, still a lot of mysteries are present about it. The new concepts of dark energy and dark matter are being explained to answer the mysterious facts. However it unfolds the rays of hope for solving the various properties and dimensions of space. Keywords: dark energy, dark matter, accelerating universe, space-time curvature, cosmological constant, gravitational lensing. 1. INTRODUCTION observations. Precision measurements of the cosmic It was Albert Einstein first to realize that empty microwave background (CMB) have shown that the space is not 'nothing'. Space has amazing properties. total energy density of the universe is very near the Many of which are just beginning to be understood. critical density needed to make the universe flat The first property that Einstein discovered is that it is (i.e. the curvature of space-time, defined in General possible for more space to come into existence. And Relativity, goes to zero on large scales). Since energy his cosmological constant makes a prediction that is equivalent to mass (Special Relativity: E = mc2), empty space can possess its own energy. Theorists this is usually expressed in terms of a critical mass still don't have correct explanation for this but they density needed to make the universe flat.
    [Show full text]
  • DARK MATTER and NEUTRINOS Arxiv:1711.10564V1 [Physics.Pop-Ph]
    Physics Education 1 dateline DARK MATTER AND NEUTRINOS Gazal Sharma1, Anu2 and B. C. Chauhan3 Department of Physics & Astronomical Science School of Physical & Material Sciences Central University of Himachal Pradesh (CUHP) Dharamshala, Kangra (HP) INDIA-176215. [email protected] [email protected] [email protected] (Submitted 03-08-2015) Abstract The Keplerian distribution of velocities is not observed in the rotation of large scale structures, such as found in the rotation of spiral galaxies. The deviation from Keplerian distribution provides compelling evidence of the presence of non-luminous matter i.e. called dark matter. There are several astrophysical motivations for investigating the dark matter in and around the galaxy as halo. In this work we address various theoretical and experimental indications pointing towards the existence of this unknown form of matter. Amongst its constituents neutrino is one of the most prospective candidates. We know the neutrinos oscillate and have tiny masses, but there are also signatures for existence of heavy and light sterile neutrinos and possibility of their mixing. Altogether, the role of neutrinos is of great interests in cosmology and understanding dark matter. arXiv:1711.10564v1 [physics.pop-ph] 23 Nov 2017 1 Introduction revealed in 2013 that our Universe contains 68:3% of dark energy, 26:8% of dark matter, and only 4:9% of the Universe is known mat- As a human being the biggest surprise for us ter which includes all the stars, planetary sys- was, that the Universe in which we live in tems, galaxies, and interstellar gas etc.. This is mostly dark.
    [Show full text]