DOCSLIB.ORG

Neutrino Cosmology and Large Scale Structure

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Neutrino Cosmology and Large Scale Structure Neutrino cosmology and large scale structure Christiane Stefanie Lorenz Pembroke College and Sub-Department of Astrophysics University of Oxford A thesis submitted for the degree of Doctor of Philosophy Trinity 2019 Neutrino cosmology and large scale structure Christiane Stefanie Lorenz Pembroke College and Sub-Department of Astrophysics University of Oxford A thesis submitted for the degree of Doctor of Philosophy Trinity 2019 The topic of this thesis is neutrino cosmology and large scale structure. First, we introduce the concepts needed for the presentation in the following chapters. We describe the role that neutrinos play in particle physics and cosmology, and the current status of the field. We also explain the cosmological observations that are commonly used to measure properties of neutrino particles. Next, we present studies of the model-dependence of cosmological neutrino mass constraints. In particular, we focus on two phenomenological parameterisations of time-varying dark energy (early dark energy and barotropic dark energy) that can exhibit degeneracies with the cosmic neutrino background over extended periods of cosmic time. We show how the combination of multiple probes across cosmic time can help to distinguish between the two components. Moreover, we discuss how neutrino mass constraints can change when neutrino masses are generated late in the Universe, and how current tensions between low- and high-redshift cosmological data might be affected from this. Then we discuss whether lensing magnification and other relativistic effects that affect the galaxy distribution contain additional information about dark energy and neutrino parameters, and how much parameter constraints can be biased when these effects are neglected. We conclude by describing current fields of active research in cosmology, and how the work presented in this thesis contributes to them. Declaration I declare that no part of this thesis has been accepted, or is currently being submitted, for any degree or diploma or certificate or any other qualification in this University or elsewhere. Except where explicit reference is made to the work of others, the work contained in this thesis is my own. Chapter 2 and parts of Chapter 1 are based on work I led that was published in Physical Review D: \Distinguishing between Neutrinos and time-varying Dark Energy through Cosmic Time [1]". I led all aspects of this work, except the implementation and running of the Fisher forecasting code which was done by Dr. David Alonso and Dr. Erminia Calabrese. Minor edits reflect comments and suggestions from the co-authors and the referee. Chapter 3 is based on work I led that was published in Physical Review D: \Time-varying neutrino mass from a supercooled phase transition: current cosmological constraints and impact on the Ωm-σ8 plane"[2]. I led most aspects of this work, apart from the theoretical part, which was led by Dr. Lena Funcke. This chapter has summarized findings from Refs. [3,4] more briefly compared to the paper [2]. Minor edits reflect comments and suggestions from the co-authors and the referee. Chapter 4 is based on work I led that was published in Physical Review D: \Impact of relativistic effects in cosmological parameter estimation"[5]. Minor edits reflect comments and suggestions from the co-authors and the referee. Christiane Stefanie Lorenz October 2019 Acknowledgements Firstly, I would like to thank my supervisors Pedro Ferreira, Erminia Calabrese and David Alonso. I have learnt very much from each of them, and I am very grateful to them for their support during the last three years. In addition, I would like to thank the people who made my transfer to astrophysics department possible, especially Erminia Calabrese, Pedro Ferreira, Jo Dunkley, Helen Johnson, Ashling Morris, Garret Cotter and my college advisor Alfons Weber. I also would like to thank the members of the cosmology group in Oxford, in particular Shahab Joudaki and Elisa Chisari, and my collaborators, Lena Funcke and Steen Hannestad. I am also grateful to the Clarendon Fund, Oxford University Press and Pembroke College for financial support that allowed me to pursue my course in Oxford. I would like to thank all the people who have supported me during the past months: most importantly my family, my friends Kilian, Lena, Andreas, Jonas, Hannah, Isa, Lena, Alice, Mariel, Harriet, Gus, Thibaud, Nina, Viki and Sonja. Especially I would like to thank Matthias who is always at my side to share both the happy and the difficult moments with me and who gives me optimism and vitality. Contents List of Figures ix List of Tables xi List of Abbreviations xiv 1 Introduction 1 1.1 The Standard Model of Cosmology............................1 1.1.1 An overview of thermal history..........................2 1.1.2 Einstein and Friedmann equations........................3 1.1.3 Distances......................................4 1.1.4 Energy densities..................................5 1.1.5 Cosmological perturbations............................6 1.2 Cosmological observations.................................7 1.2.1 The cosmic microwave background........................7 1.2.2 Supernovae..................................... 10 1.2.3 Baryonic acoustic oscillations........................... 10 1.2.4 Galaxy surveys................................... 11 1.2.5 Sunyaev-Zeldovich cluster counts......................... 13 1.2.6 Cosmic microwave background lensing...................... 14 1.3 Neutrinos.......................................... 15 1.3.1 Neutrino oscillations................................ 15 1.3.2 Neutrino mass mechanisms............................ 17 1.3.3 The evolution of cosmic neutrinos........................ 19 1.3.4 Neutrinos and BBN................................ 23 1.3.5 Current constraints of neutrino parameters................... 23 1.3.6 Open questions about neutrinos.......................... 24 1.3.6.1 How many neutrino types are there?.................. 24 1.3.6.2 Are neutrinos Majorana or Dirac particles?.............. 25 1.3.7 What are the absolute neutrino masses?..................... 25 1.4 Statistical methods in cosmology............................. 26 v 1.4.1 Fisher forecasts................................... 26 1.4.2 Monte Carlo Markov chains............................ 26 1.5 Overview of this thesis................................... 27 2 Neutrinos and time-varying dark energy 29 2.1 Introduction......................................... 29 2.2 Theoretical degeneracies.................................. 30 2.2.1 Time-varying dark energy............................. 32 2.2.1.1 Barotropic dark energy......................... 32 2.2.1.2 Early dark energy............................ 33 2.2.2 Observations at different cosmic times...................... 34 2.3 Constraints from current data............................... 35 2.3.0.1 Single-probe degeneracies........................ 36 2.3.0.2 Multi-probe analysis........................... 38 2.4 Future predictions..................................... 39 2.5 Conclusion......................................... 44 3 Time-varying neutrino masses 45 3.1 Introduction......................................... 45 3.2 Time-varying neutrino mass model............................ 47 3.2.1 Theoretical Foundations.............................. 47 3.2.2 Cosmological Observables............................. 51 3.3 Analysis methodology................................... 55 3.4 Results............................................ 56 3.4.1 Cosmological Mass Limits............................. 56 3.4.2 The Ωm-σ8 plane................................. 58 3.5 Summary and concluding remarks............................ 61 4 The impact of relativistic effects in Large Scale Structure 65 4.1 Observables and Large Scale Effects........................... 66 4.2 Methodology........................................ 68 4.2.1 The space of parameters.............................. 68 4.2.2 Fisher matrix forecasting formalism....................... 70 4.2.3 Upcoming surveys................................. 72 4.2.3.1 CMB Stage 4............................... 72 4.2.3.2 Large Synoptic Survey Telescope.................... 73 4.3 Results............................................ 75 4.3.1 Impact on dark energy and neutrino mass.................... 76 4.3.2 Impact on scalar-tensor theories......................... 77 vi 4.3.3 Impact on primordial non-Gaussianity...................... 78 4.3.4 Impact of magnification uncertainties...................... 80 4.4 Discussion.......................................... 81 5 Conclusions 87 5.1 Open questions in modern cosmology........................... 87 5.2 Summary of findings of this thesis and further remarks................. 89 A Complete expressions for the corrections to the number counts of galaxies 93 Bibliography 95 vii List of Figures 1.1 Cosmic microwave background temperature anisotropies power spectrum.......9 1.2 Evolution of neutrinos through cosmic time....................... 18 1.3 Impact of changes in Neff on the CMB temperature anisotropy power spectrum... 21 1.4 Impact of changes in Σmν on the matter power spectrum P (k)............ 22 2.1 Evolution of neutrinos and dark energy through cosmic time.............. 31 2.2 Single-probe analysis for barotropic dark energy model................. 36 2.3 Single-probe analysis for early dark energy model.................... 37 2.4 Multi-probe analysis for barotropic dark energy..................... 39 2.5 Multi-probe analysis for early dark energy........................ 40
Load more

Recommended publications
  • PRESS RELEASE Solved: the Mystery of the Expansion of the Universe
    PRESS RELEASE Geneva | March 10th, 2020 The earth, solar system, entire Milky Way and the few thousand ga- Solved: laxies closest to us move in a vast “bubble” that is 250 million light years in diameter, where the average density of matter is half as large the mystery as for the rest of the universe. This is the hypothesis put forward by a theoretical physicist from the University of Geneva (UNIGE) to solve of the expansion a conundrum that has been splitting the scientific community for a decade: at what speed is the universe expanding? Until now, at least of the universe two independent calculation methods have arrived at two values that are different by about 10% with a deviation that is statistically A UNIGE researcher has irreconcilable. This new approach, which is set out in the journal Phy- solved a scientific sics Letters B, erases this divergence without making use of any “new controversy about the speed physics”. of the expansion The universe has been expanding since the Big Bang occurred 13.8 bil- of the universe by lion years ago – a proposition first made by the Belgian canon and suggesting that it is not physicist Georges Lemaître (1894-1966), and first demonstrated by Edwin Hubble (1889-1953). The American astronomer discovered in totally homogeneous on a 1929 that every galaxy is pulling away from us, and that the most dis- large scale. tant galaxies are moving the most quickly. This suggests that there was a time in the past when all the galaxies were located at the same spot, a time that can only correspond to the Big Bang.
    [Show full text]
  • Lectures and Seminars, Trinity Term 2015
    WEDNESDay 22 april 2015 • SUpplEMENT (2) TO NO 5092 • VOl 145 Gazette Supplement Lectures and Seminars, Trinity term 2015 Romanes Lecture 462 Experimental psychology Buddhist Studies Orthopaedics, rheumatology and COMPAS Musculoskeletal Sciences Hebrew and Jewish Studies University Administration pathology Hindu Studies and Services 462 pharmacology Museum of the History of Science Disability Lecture physiology, anatomy and Genetics islamic Studies population Health reuters institute for the Study of Humanities 462 psychiatry Journalism Foundation for law, Justice and Society TOrCH | The Oxford research Centre in Social Sciences 470 the Humanities learning institute Maison Française rothermere american institute interdisciplinary research Methods Oxford Martin School Classics Sanjaya lall Memorial Trust population ageing English language and literature anthropology and Museum Ethnography ian ramsey Centre History Saïd Business School linguistics, philology and phonetics Economics Colleges, Halls and Societies 482 Medieval and Modern languages Education Music interdisciplinary area Studies all Souls Oriental Studies international Development (Queen Balliol philosophy Elizabeth House) Green Templeton Theology and religion Oxford internet institute Keble Law lady Margaret Hall Mathematical, Physical and politics and international relations linacre Life Sciences 466 Social policy and intervention lincoln Socio-legal Studies Chemistry Magdalen Sociology Computer Science Mansfield Nuffield Earth Sciences Department for Continuing Queen’s Engineering
    [Show full text]
  • Einstein's Wrong
    Einstein’s wrong way: from STR to GTR Adrian Ferent I discovered a new Gravitation theory which breaks the wall of Planck scale! Abstract My Nobel Prize - Discoveries “Starting from STR, it is not possible to find a Quantum Gravity theory” Adrian Ferent “Einstein was on the wrong way: from STR to GTR” Adrian Ferent “Starting from STR, Einstein was not able to explain Gravitation” Adrian Ferent “Starting from STR, Einstein was not able to explain Gravitation, he calculated Gravitation” Adrian Ferent “Einstein's equivalence principle is wrong because the gravitational force experienced locally is caused by a negative energy, gravitons energy and the force experienced by an observer in a non-inertial (accelerated) frame of reference is caused by a positive energy.” Adrian Ferent “Because Einstein's equivalence principle is wrong, Einstein’s gravitation theory is wrong.” Adrian Ferent “Because Einstein’s gravitation theory is wrong, LQG, String theory… are wrong theories” Adrian Ferent “Einstein bent the space, Ferent unbent the space” Adrian Ferent 1 “Einstein bent the time, Ferent unbent the time” Adrian Ferent “I am the first who Quantized the Gravitational Field!” Adrian Ferent “I quantized the gravitational field with gravitons” Adrian Ferent “Gravitational field is a discrete function” Adrian Ferent “Gravitational waves are carried by gravitons” Adrian Ferent In STR and GTR there are continuous functions. This is another proof that LIGO is a fraud. The 2017 Nobel Prize in Physics has been awarded for a project, the Laser Interferometer Gravitational-wave Observatory (LIGO) not for a scientific discovery; they did not detect anything because Einstein’s gravitational waves do not exist.
    [Show full text]
  • Extracting Cosmology from High Resolution CMB Data *Focused on ACT and SO
    Extracting cosmology from high resolution CMB data *focused on ACT and SO Jo Dunkley, Princeton University May 23, 2018 Jo Dunkley Cosmic Microwave Background T=2.7K ∆T/T ~0.00001 Also polarization: Rep.Two-point statistics: Prog. Phys. 81 (2018) 044901 Report on Progress TxT TxE BxB ExE Staggs, JD, Page 2018 review Figure 3. Example of recent CMB power spectra from [50–54]. Left. TT (top) and EE (bottom) data and power spectra plotted with logarithmic y axes. The TT and EE oscillations are out of phase by ∼π/2 as expected for acoustic oscillations (see section 1.4) since TT and EE trace density and velocity, respectively. The TT spectrum at low ℓ, corresponding to superhorizon scales at decoupling (see section 2.1), has post-decoupling contributions from gravitational redshifting of the photons as they pass through evolving potential wells, known as the integrated Sachs-Wolfe (ISW) effect [55, 56]. The EE spectrum peaks at higher ℓ than TT both because it lacks the ISW effect, and because the acoustic oscillation velocity gradients sourcing the polarization grow with k and thus with ℓ. The spectra are suppressed at large ℓ due to photon diffusion from smaller regions of space, also called Silk damping [57], and to geometric effects from compressing the 3d structure to 2d spectra. Right. TE with linear y axis. Since the ISW effect does not change the polarization, the negative peak at ℓ = 150 in TE confrmed that some of the largest scale features in the CMB are primordial, and not just late-time effects [58–60].
    [Show full text]
  • Nobel Lecture: Accelerating Expansion of the Universe Through Observations of Distant Supernovae*
    REVIEWS OF MODERN PHYSICS, VOLUME 84, JULY–SEPTEMBER 2012 Nobel Lecture: Accelerating expansion of the Universe through observations of distant supernovae* Brian P. Schmidt (published 13 August 2012) DOI: 10.1103/RevModPhys.84.1151 This is not just a narrative of my own scientific journey, but constant, and suggested that Hubble’s data and Slipher’s also my view of the journey made by cosmology over the data supported this conclusion (Lemaˆitre, 1927). His work, course of the 20th century that has lead to the discovery of the published in a Belgium journal, was not initially widely read, accelerating Universe. It is complete from the perspective of but it did not escape the attention of Einstein who saw the the activities and history that affected me, but I have not tried work at a conference in 1927, and commented to Lemaˆitre, to make it an unbiased account of activities that occurred ‘‘Your calculations are correct, but your grasp of physics is around the world. abominable.’’ (Gaither and Cavazos-Gaither, 2008). 20th Century Cosmological Models: In 1907 Einstein had In 1928, Robertson, at Caltech (just down the road from what he called the ‘‘wonderful thought’’ that inertial accel- Edwin Hubble’s office at the Carnegie Observatories), pre- eration and gravitational acceleration were equivalent. It took dicted the Hubble law, and claimed to see it when he com- Einstein more than 8 years to bring this thought to its fruition, pared Slipher’s redshift versus Hubble’s galaxy brightness his theory of general Relativity (Norton and Norton, 1984)in measurements, but this observation was not substantiated November, 1915.
    [Show full text]
  • Challenges to Self-Acceleration in Modified Gravity from Gravitational
    Physics Letters B 765 (2017) 382–385 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Challenges to self-acceleration in modified gravity from gravitational waves and large-scale structure ∗ Lucas Lombriser , Nelson A. Lima Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK a r t i c l e i n f o a b s t r a c t Article history: With the advent of gravitational-wave astronomy marked by the aLIGO GW150914 and GW151226 Received 2 September 2016 observations, a measurement of the cosmological speed of gravity will likely soon be realised. We show Received in revised form 19 December 2016 that a confirmation of equality to the speed of light as indicated by indirect Galactic observations Accepted 19 December 2016 will have important consequences for a very large class of alternative explanations of the late-time Available online 27 December 2016 accelerated expansion of our Universe. It will break the dark degeneracy of self-accelerated Horndeski Editor: M. Trodden scalar–tensor theories in the large-scale structure that currently limits a rigorous discrimination between acceleration from modified gravity and from a cosmological constant or dark energy. Signatures of a self-acceleration must then manifest in the linear, unscreened cosmological structure. We describe the minimal modification required for self-acceleration with standard gravitational-wave speed and show that its maximum likelihood yields a 3σ poorer fit to cosmological observations compared to a cosmological constant. Hence, equality between the speeds challenges the concept of cosmic acceleration from a genuine scalar–tensor modification of gravity.
    [Show full text]
  • Issues in Physics & Astronomy
    Issues in Physics & Astronomy Board on Physics and Astronomy · The National Academies · Washington, D.C. · 202-334-3520 · national-academies.org/bpa · Summer 2009 Challenges and Opportunities in New Materials Synthesis and Crystal Growth James C. Lancaster, BPA Staff or much of the past 60 years, the Madison), was charged with the respon- ficiently interesting scientifically or relevant U.S. research community dominat- sibility of assessing the health of research for an application—or as often happens, Fed the discovery of new crystalline activities in the United States in this field, both—large single crystals of that material materials and the growth of large single identifying future opportunities and rec- are needed for detailed study. Because of crystals. These efforts placed the country at ommending strategies for the United States common heritage, shared resources, and the forefront of fundamental advances in to reinvigorate its efforts and thereby return strong educational bonds, it is natural to condensed-matter sciences and fueled the to a position of leadership in this field. The combine these related activities—the dis- development of many of the new technolo- committee issued its report this past spring. covery and growth of crystalline materials gies at the core of U.S. economic growth. The two activities in this field— (DGCM)—in a single study. The growth of The opportunities offered by future devel- discovering new crystalline materials and thin, two-dimensional crystalline films also opments in this field remain as promising growing large crystals of these materials— is included in this study because it shares as the achievements of the past.
    [Show full text]
  • Arxiv:2009.07772V2 [Astro-Ph.CO] 2 Nov 2020
    Draft version November 3, 2020 Typeset using LATEX preprint2 style in AASTeX63 The Atacama Cosmology Telescope: Weighing distant clusters with the most ancient light Mathew S. Madhavacheril,1 Cristobal´ Sifon,´ 2 Nicholas Battaglia,3 Simone Aiola,4 Stefania Amodeo,3 Jason E. Austermann,5 James A. Beall,5 Daniel T. Becker,5 J. Richard Bond,6 Erminia Calabrese,7 Steve K. Choi,8, 3 Edward V. Denison,5 Mark J. Devlin,9 Simon R. Dicker,9 Shannon M. Duff,5 Adriaan J. Duivenvoorden,10 Jo Dunkley,11, 10 Rolando Dunner,¨ 12 Simone Ferraro,13 Patricio A. Gallardo,8 Yilun Guan,14 Dongwon Han,15 J. Colin Hill,16, 4 Gene C. Hilton,5 Matt Hilton,17, 18 Johannes Hubmayr,5 Kevin M. Huffenberger,19 John P. Hughes,20 Brian J. Koopman,21 Arthur Kosowsky,14 Jeff Van Lanen,5 Eunseong Lee,22 Thibaut Louis,23 Amanda MacInnis,15 Jeffrey McMahon,24, 25, 26, 27 Kavilan Moodley,17, 18 Sigurd Naess,4 Toshiya Namikawa,28 Federico Nati,29 Laura Newburgh,21 Michael D. Niemack,8, 3 Lyman A. Page,10 Bruce Partridge,30 Frank J. Qu,28 Naomi C. Robertson,31, 32 Maria Salatino,33, 34 Emmanuel Schaan,13 Alessandro Schillaci,35 Benjamin L. Schmitt,36 Neelima Sehgal,15 Blake D. Sherwin,28, 32 Sara M. Simon,37 David N. Spergel,4, 11 Suzanne Staggs,10 Emilie R. Storer,10 Joel N. Ullom,5 Leila R. Vale,5 Alexander van Engelen,38 Eve M. Vavagiakis,8 Edward J. Wollack,39 and Zhilei Xu9 1Centre for the Universe, Perimeter Institute, Waterloo, ON N2L 2Y5, Canada 2Instituto de F´ısica, Pontificia Universidad Cat´olica de Valpara´ıso,Casilla 4059, Valpara´ıso,Chile 3Department of Astronomy, Cornell University, Ithaca, NY 14853 USA 4Center for Computational Astrophysics, Flatiron Institute, 162 5th Avenue, New York, NY, USA 10010 5NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO, USA 80305 6Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St.
    [Show full text]
  • Oxford Physics Newsletter
    Spring 2011, Number 1 Department of Physics Newsletter elcome to the first edition of Oxford Physics creates new solar-cell the Department technology Wof Physics Newsletter. In this takes place to generate free electrons, which edition, we describe some of Henry Snaith contribute to a current in an external circuit. The the wide range of research original dye-sensitised solar cell used a liquid currently being carried out in The ability to cheaply and efficiently harness the power of electrolyte as the “p-type” material. the Oxford Physics Department, the Sun is crucial to trying to slow The work at Oxford has focused on effectively and also describe some of down climate change. Solar cells replacing the liquid electrolyte with p-type the other activities where we aim to produce electricity directly from sunlight, organic semiconductors. This solid-state system seek to engage the public in but are currently too expensive to have significant offers great advantages in ease of processing and impact. A new “spin-out” company, Oxford science and communicate with scalability. Photovoltaics Ltd, has recently been created to potential future physicists. I commercialise solid-state dye-sensitised solar Over the next two to three years, Oxford hope you enjoy reading it. If you cell technology developed at the Clarendon Photovoltaics will scale the technology from laboratory to production line, with the projected have passed through Oxford Laboratory. market being photovoltaic cells integrated into Physics as an undergraduate In conventional photovoltaics, light is absorbed windows and cladding for buildings. or postgraduate student, or in in the bulk of a slab of semiconducting material any other capacity, we would and the photogenerated charge is collected at metallic electrodes.
    [Show full text]
  • Letter of Interest Fundamental Physics with Gravitational Wave Detectors
    Snowmass2021 - Letter of Interest Fundamental physics with gravitational wave detectors Thematic Areas: (check all that apply /) (CF1) Dark Matter: Particle Like (CF2) Dark Matter: Wavelike (CF3) Dark Matter: Cosmic Probes (CF4) Dark Energy and Cosmic Acceleration: The Modern Universe (CF5) Dark Energy and Cosmic Acceleration: Cosmic Dawn and Before (CF6) Dark Energy and Cosmic Acceleration: Complementarity of Probes and New Facilities (CF7) Cosmic Probes of Fundamental Physics (TF09) Cosmology Theory (TF10) Quantum Information Science Theory Contact Information: Emanuele Berti (Johns Hopkins University) [[email protected]], Vitor Cardoso (Instituto Superior Tecnico,´ Lisbon) [[email protected]], Bangalore Sathyaprakash (Pennsylvania State University & Cardiff University) [[email protected]], Nicolas´ Yunes (University of Illinois at Urbana-Champaign) [[email protected]] Authors: (see long author lists after the text) Abstract: (maximum 200 words) Gravitational wave detectors are formidable tools to explore black holes and neutron stars. These com- pact objects are extraordinarily efficient at producing electromagnetic and gravitational radiation. As such, they are ideal laboratories for fundamental physics and they have an immense discovery potential. The detection of merging black holes by third-generation Earth-based detectors and space-based detectors will provide exquisite tests of general relativity. Loud “golden” events and extreme mass-ratio inspirals can strengthen the observational evidence for horizons by mapping the exterior spacetime geometry, inform us on possible near-horizon modifications, and perhaps reveal a breakdown of Einstein’s gravity. Measure- ments of the black-hole spin distribution and continuous gravitational-wave searches can turn black holes into efficient detectors of ultralight bosons across ten or more orders of magnitude in mass.
    [Show full text]
  • Dark Energy Vs. Modified Gravity Arxiv:1601.06133V4 [Astro-Ph.CO]
    Dark Energy vs. Modified Gravity Austin Joyce,1 Lucas Lombriser,2 and Fabian Schmidt3 1Enrico Fermi Institute and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637; email: [email protected] 2Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, U.K.; email: [email protected] 3Max-Planck-Institute for Astrophysics, D-85748 Garching, Germany; email: [email protected] Ann. Rev. Nuc. Part. Sc. 2016. AA:1{29 Keywords Copyright c 2016 by Annual Reviews. All rights reserved cosmology, dark energy, modified gravity, structure formation, large-scale structure Abstract Understanding the reason for the observed accelerated expansion of the Universe represents one of the fundamental open questions in physics. In cosmology, a classification has emerged among physical models for the acceleration, distinguishing between Dark Energy and Modified Gravity. In this review, we give a brief overview of models in both categories as well as their phenomenology and characteristic observable signatures in cosmology. We also introduce a rigorous distinction be- tween Dark Energy and Modified Gravity based on the strong and weak arXiv:1601.06133v4 [astro-ph.CO] 14 Jun 2016 equivalence principles. 1 Contents 1. INTRODUCTION ............................................................................................2 2. OVERVIEW: DARK ENERGY AND MODIFIED GRAVITY ................................................3 2.1. Dark Energy (DE).......................................................................................3
    [Show full text]
  • Year in Review
    Year in review For the year ended 31 March 2017 Trustees2 Executive Director YEAR IN REVIEW The Trustees of the Society are the members Dr Julie Maxton of its Council, who are elected by and from Registered address the Fellowship. Council is chaired by the 6 – 9 Carlton House Terrace President of the Society. During 2016/17, London SW1Y 5AG the members of Council were as follows: royalsociety.org President Sir Venki Ramakrishnan Registered Charity Number 207043 Treasurer Professor Anthony Cheetham The Royal Society’s Trustees’ report and Physical Secretary financial statements for the year ended Professor Alexander Halliday 31 March 2017 can be found at: Foreign Secretary royalsociety.org/about-us/funding- Professor Richard Catlow** finances/financial-statements Sir Martyn Poliakoff* Biological Secretary Sir John Skehel Members of Council Professor Gillian Bates** Professor Jean Beggs** Professor Andrea Brand* Sir Keith Burnett Professor Eleanor Campbell** Professor Michael Cates* Professor George Efstathiou Professor Brian Foster Professor Russell Foster** Professor Uta Frith Professor Joanna Haigh Dame Wendy Hall* Dr Hermann Hauser Professor Angela McLean* Dame Georgina Mace* Dame Bridget Ogilvie** Dame Carol Robinson** Dame Nancy Rothwell* Professor Stephen Sparks Professor Ian Stewart Dame Janet Thornton Professor Cheryll Tickle Sir Richard Treisman Professor Simon White * Retired 30 November 2016 ** Appointed 30 November 2016 Cover image Dancing with stars by Imre Potyó, Hungary, capturing the courtship dance of the Danube mayfly (Ephoron virgo). YEAR IN REVIEW 3 Contents President’s foreword .................................. 4 Executive Director’s report .............................. 5 Year in review ...................................... 6 Promoting science and its benefits ...................... 7 Recognising excellence in science ......................21 Supporting outstanding science .....................
    [Show full text]