DOCSLIB.ORG

Profile of James Peebles, Michel Mayor, and Didier Queloz: 2019 Nobel Laureates in Physics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Profile of James Peebles, Michel Mayor, and Didier Queloz: 2019 Nobel Laureates in Physics PROFILE Profile of James Peebles, Michel Mayor, and Didier Queloz: 2019 Nobel Laureates in Physics PROFILE Neta A. Bahcalla,1 and Adam Burrowsa Mankind has long been fascinated by the mysteries of our Universe: How old and how big is the Universe? How did the Universe begin and how is it evolving? What is the composition of the Universe and the nature of its dark matter and dark energy? What is our Earth’s place in the cosmos and are there other planets (and life) around other stars? The 2019 Nobel Prize in Physics honors three pioneering scientists for their fundamental contributions to these cosmic questions—Professors James Peebles of Princeton University, Michel Mayor of the University of Geneva, and Didier Queloz of the University of Geneva and the University of Cambridge—“for contributions (Left) Profs. James Peebles (Princeton University), (Center) Michel Mayor (University of Geneva), and (Right) Didier Queloz (University of Geneva and the University of to our understanding of the evolution of the universe Cambridge). Jessica Gow, Frank Perry, Isabel Infantes/AFP/Scanpix Sweden. and Earth’s place in the cosmos,” with one half to James Peebles “for theoretical discoveries in physical cosmology,” and the other half jointly to Michel Mayor The science of cosmology started in earnest mostly and Didier Queloz “for the discovery of an exoplanet with Einstein’s theory of general relativity. Alexander orbiting a solar-type star.” Friedman, Willem de Sitter, and Georges Lemaître, using Einstein’s equations, recognized that our Universe The Evolution of the Universe is not static, it must be either expanding or contracting James Peebles was born in Southern Manitoba, Can- and Hubble’s remarkable observational discovery of the ada, in 1935; he moved to Princeton University for expanding Universe in 1929 confirmed this. The ob- graduate school in 1958 and remained in Princeton as served expansion implied that the Universe must have the Albert Einstein Professor of Physics (now emeritus) started from a compact state, but this idea took a long for his entire career. He has long been considered one time to be accepted. In the 1940s, George Gamow, of the fathers of modern cosmology, the science of the Ralph Alpher, and Robert Herman investigated the origin and evolution of the Universe. As the Nobel consequences of a hot Big Bang—a Universe that committee states, “James Peebles took the cosmos, started from a small, very dense, and very hot stage— with its billions of galaxies and galaxy clusters. His the- and made predictions that could be tested. They cal- oretical framework, developed over two decades, is the culated that light elements should have been formed foundation of our modern understanding of the Uni- in the hot Big Bang and that a huge amount of radia- verse’s history, from the Big-Bang to the present day.” tion, the remnant of which (the cosmic microwave The spectacular advances in cosmology over the past background, or CMB) should still fill the entire Universe half a century have been driven by a combination of today, must have been generated. both observations and theory. The revelation that our However, when Peebles began working in cos- Universe has begun from a hot and dense Big Bang mology in the 1960s, at the invitation of his Princeton 13.8 billion years ago and has been expanding and mentor and friend, Prof. Robert Dicke, the field was evolving ever since, under the influence of the still vague, not well quantified, and had only modest mysterious dark matter and dark energy that dominate experimental support. In 1965, Peebles, with his the cosmos, in addition to the ∼5% baryons that makes colleagues Dicke, Wilkinson, and Roll, recalculated up the stars, planets, and all of us, is a triumph for both the black-body temperature of the remnant radiation observational and theoretical science. expected from the aforementioned hot Big Bang aDepartment of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 This article is part of a series of articles in PNAS highlighting the discoveries and profiling the award winners of the Nobel Prize. Author contributions: N.A.B. and A.B. wrote the paper. The authors declare no competing interest. Published under the PNAS license. 1To whom correspondence may be addressed. Email: [email protected]. First published January 13, 2020. www.pnas.org/cgi/doi/10.1073/pnas.1920833117 PNAS | January 14, 2020 | vol. 117 | no. 2 | 799–801 Downloaded by guest on September 30, 2021 and estimated it to be ∼10 K today, and Dicke and Universe. Moreover, Peebles has also authored sev- collaborators began to look for it. That same year the eral outstanding books in cosmology, used by gen- signal of the CMB was indeed detected by Arno erations of students and scientists at all levels: Physical Penzias and Robert Wilson at Bell Labs in Holmdel, Cosmology (3), Large Scale Structure of the Universe New Jersey. Penzias and Wilson conferred with (4), Principles of Physical Cosmology (5), Finding the Big Peebles and Dicke to understand the observed sig- Bang (6), and his most recent book just being com- nal, which corresponded to a radiation temperature pleted Cosmology’sCentury(7). of 3.5 K. The discovery of the CMB radiation con- “Just about every advance in our understanding firmed the hot Big Bang model and opened the door of cosmology has been boosted by the work of Jim to a greatly improved understanding of physical Peebles,” says Princeton cosmologist Jeremiah Ostriker. cosmology.* Penzias and Wilson were awarded the “Big Bang nucleosynthesis, the growth of cosmic 1978 Nobel prize for their observational discovery of structure, the existence of dark matter, and so many the CMB. other advances in our understanding were shepherded With the discovery of the CMB, Peebles investi- by Jim Peebles’ work and wisdom.” Thanks to his ef- gated its impact on the formation of nuclei in the first forts, cosmology is now a solid, robust scientific field, few minutes of the hot dense Universe, the so-called Big with both theory and observation going hand-in-hand Bang nucleosynthesis. While Big Bang nucleosynthesis to reveal the amazing and evolving Universe. While had been worked on previously, the influence of the hot some fundamental questions remain open—including CMB has not been considered in detail. Peebles used what is the dark matter and what is the nature of the the measured temperature of the CMB, extrapolated to mysterious dark energy—cosmologists can now explain, the hot temperature during the early Universe, and quantify, and make future predictions for the evolution of calculated the resulting nucleosynthesis. From his cal- the Universe. culations of the hot Big Bang, Peebles determined the “Jim is one of the true giants in the field,” wrote abundance of light elements created in the early Uni- Paul Steinhardt, Peebles’ colleague at Princeton. verse. His estimate for primordial helium of 27 to 30% of “His work transformed our understanding of the hot, all nuclei by mass is similar to the currently observed expanding Universe from qualitative to precise, revealed primordial helium abundance (25%). the existence of dark matter, and pointed out the puz- Peebles continued his exploration of physical cos- zles that remain.” mology in numerous areas. He predicted the tem- perature fluctuations in the spectrum of the CMB, the Earth’s Place in the Cosmos primordial seeds of structure formation in the Uni- Before 1995, a few astronomers were trying to de- verse; it took many years of continuously improved velop spectroscopic techniques with which to mea- experimental techniques to finally detect the CMB sure the Doppler wobble of a parent star due to the fluctuations (first with the cosmic background ex- possible presence of planetary companions. Some plorer mission, and later with CMB measurements by considered this indirect method more viable than di- BOOMERanG [the Ballon observations of millimetric rect imaging, since the dim planet would be difficult extragalactic radiation and geophysics experiment], to detect from under the glare of the parent star. An- the Wilkinson microwave anisotropy map, and the other indirect technique being pursued was astrome- Planck mission). He helped provide theoretical evi- try, whereby the reflex motion of the star due to the dence for dark matter in spiral galaxies by showing gravitational tug of an orbiting planetary companion ’ that they would not be stable at their observed flat- would signal the planet s presence. A Jupiter-mass tened shape without a more stabilizing gravitational planet at the distance that Jupiter is from the Sun, potential of a massive halo to surround them. Peebles but orbiting a nearby solar-mass star, would induce ∼ −1 pioneered the cosmological model of “cold dark mat- a stellar wobble of 12 m s (onlyabitfasterthan ter,” which is the best current model for dark matter, a human can run) in the stellar spectrum and an as- ∼ based on evidence from observations of large-scale trometric displacement of 0.005 astronomical units structure. He was a pioneer in the quantitative study (AU). One AU is the distance between the Earth and of the observed distribution of galaxies, using the the Sun. The latter at a distance from the solar system ∼ powerful statistical tools of the two-point and higher- of 10 parsecs is equivalent to an angular displacement ∼ order correlation functions, and applied these tools of the nearby star of 0.5 milliarcsecs. However, even to large surveys of galaxies. Peebles pioneered models now, almost 25 years since 1995, such astrometric de- for cosmic structure formation and evolution through tection techniques have yet to prove themselves. This left the Doppler technique. However, astrono- the gravitational instability picture in an expanding − mers were routinely achieving only ∼200 m s 1.Some astronomers, using hydrogen fluoride or iodine in- *Penzias and Wilson decided to publish their results simulta- ternal spectral calibrators and good thermal control, −1 neously with Dicke and Peebles; in the first paper, Dicke, Peebles, had achieved ∼20 m s , but had discovered noth- Roll, and Wilkinson (1), showed the importance of the CMB as ing.
Load more

Recommended publications
  • Big Bang Blunder Bursts the Multiverse Bubble
    WORLD VIEW A personal take on events IER P P. PA P. Big Bang blunder bursts the multiverse bubble Premature hype over gravitational waves highlights gaping holes in models for the origins and evolution of the Universe, argues Paul Steinhardt. hen a team of cosmologists announced at a press world will be paying close attention. This time, acceptance will require conference in March that they had detected gravitational measurements over a range of frequencies to discriminate from fore- waves generated in the first instants after the Big Bang, the ground effects, as well as tests to rule out other sources of confusion. And Worigins of the Universe were once again major news. The reported this time, the announcements should be made after submission to jour- discovery created a worldwide sensation in the scientific community, nals and vetting by expert referees. If there must be a press conference, the media and the public at large (see Nature 507, 281–283; 2014). hopefully the scientific community and the media will demand that it According to the team at the BICEP2 South Pole telescope, the is accompanied by a complete set of documents, including details of the detection is at the 5–7 sigma level, so there is less than one chance systematic analysis and sufficient data to enable objective verification. in two million of it being a random occurrence. The results were The BICEP2 incident has also revealed a truth about inflationary the- hailed as proof of the Big Bang inflationary theory and its progeny, ory. The common view is that it is a highly predictive theory.
    [Show full text]
  • Arxiv:1307.1848V3 [Hep-Th] 8 Nov 2013 Tnadmdla O Nris N H Urn Ig Vacuum Higgs Data
    Local Conformal Symmetry in Physics and Cosmology Itzhak Bars Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, 90089-0484, USA, Paul Steinhardt Physics Department, Princeton University, Princeton NJ08544, USA, Neil Turok Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5, Canada. (Dated: July 7, 2013) Abstract We show how to lift a generic non-scale invariant action in Einstein frame into a locally conformally-invariant (or Weyl-invariant) theory and present a new general form for Lagrangians consistent with Weyl symmetry. Advantages of such a conformally invariant formulation of particle physics and gravity include the possibility of constructing geodesically complete cosmologies. We present a conformal-invariant version of the standard model coupled to gravity, and show how Weyl symmetry may be used to obtain unprecedented analytic control over its cosmological solutions. Within this new framework, generic FRW cosmologies are geodesically complete through a series of big crunch - big bang transitions. We discuss a new scenario of cosmic evolution driven by the Higgs field in a “minimal” conformal standard model, in which there is no new physics beyond the arXiv:1307.1848v3 [hep-th] 8 Nov 2013 standard model at low energies, and the current Higgs vacuum is metastable as indicated by the latest LHC data. 1 Contents I. Why Conformal Symmetry? 3 II. Why Local Conformal Symmetry? 8 A. Global scale invariance 8 B. Local scale invariance 11 III. General Weyl Symmetric Theory 15 A. Gravity 15 B. Supergravity 22 IV. Conformal Cosmology 25 Acknowledgments 31 References 31 2 I. WHY CONFORMAL SYMMETRY? Scale invariance is a well-known symmetry [1] that has been studied in many physical contexts.
    [Show full text]
  • Traversing Cosmological Singularities, Complete Journeys Through Spacetime Including Antigravity
    Traversing Cosmological Singularities Complete Journeys Through Spacetime Including Antigravity ∗ Itzhak Bars Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA A unique description of the Big Crunch-Big Bang transition is given at the classical gravity level, along with a complete set of homogeneous, isotropic, analytic solutions in scalar-tensor cosmology, with radiation and curvature. All solutions repeat cyclically; they have been obtained by using conformal gauge symmetry (Weyl symmetry) as a powerful tool in cosmology, and more generally in gravity. The significance of the Big Crunch-Big Bang transition is that it provides a model inde- pendent analytic resolution of the singularity, as an unambiguous and unavoidable solution of the equations at the classical gravitational physics level. It is controlled only by geometry (including anisotropy) and only very general features of matter coupled to gravity, such as kinetic energy of a scalar field, and radiation due to all forms of relativistic matter. This analytic resolution of the singularity is due to an attractor mechanism created by the leading terms in the cosmological equa- tion. It is unique, and it is unavoidable in classical relativity in a geodesically complete geometry. Its counterpart in quantum gravity remains to be understood. I. INTRODUCTION AND SUMMARY OF RESULTS Resolving the big bang singularity is one of the central challenges for fundamental physics and cosmology. The issue arises naturally in the context of classical relativity due to the geodesically incomplete nature of the singular spacetime [1]-[2]. The resolution may not be completed until the physics is understood in the context of quantum gravity.
    [Show full text]
  • First Nuclear Test Created 'Impossible' Quasicrystals
    formed in a collision between two asteroids in the early Solar System, Steinhardt says. Some of the lab-made quasicrystals were also pro- duced by smashing materials together at high speed, so Steinhardt and his team wondered whether the shockwaves from nuclear explo- sions might form quasicrystals, too. ‘Slicing and dicing’ In the aftermath of the Trinity test — the first detonation of a nuclear bomb, which took place on 16 July 1945 at New Mexico’s Alamo- gordo Bombing Range — researchers found a vast field of greenish glassy material that had formed from the liquefaction of desert sand. They dubbed this trinitite. The bomb had been detonated on top of a 30-metre-high tower laden with sensors and their cables. As a result, some of the trinitite that formed had reddish inclusions, says Stein- LUCA BINDI, PAUL J. STEINHARDT BINDI, PAUL LUCA hardt. “It was a fusion of natural material with This sample of red trinitite was found to contain a previously unknown type of quasicrystal. copper from the transmission lines.” Quasi- crystals often form from elements that would not normally combine, so Steinhardt and his colleagues thought samples of the red trinitite FIRST NUCLEAR TEST would be a good place to look. “Over the course of ten months, we were slic- CREATED ‘IMPOSSIBLE’ ing and dicing, looking at all sorts of minerals,” Steinhardt says. “Finally, we found a tiny grain.” QUASICRYSTALS The quasicrystal has the same kind of icosa- hedral symmetry as the one in Shechtman’s Researchers have discovered the once-controversial original discovery. “The dominance of silicon in its structure is structures in the aftermath of a 1945 bomb test.
    [Show full text]
  • Burt Alan Ovrut Curriculum Vitae Personal
    BURT ALAN OVRUT CURRICULUM VITAE PERSONAL: Marital Status: Widower Birthplace: New York, NY, USA ADDRESS: Office: University of Pennsylvania Department of Physics Philadelphia, PA 19104 (215) 898-3594 Home: 324 Conshohocken State Road Penn Valley, PA 19072 (215) 668-1890 EDUCATION: Ph.D. - The University of Chicago, June 1978 Thesis - An SP(4) x U(1) Gauge Model of the Weak and Electromagnetic Interactions Thesis Advisors - Professors Benjamin W. Lee and Yoichiro Nambu RESEARCH POSITIONS: July 1990- present Full Professor, Theory Group University of Pennsylvania, Philadelphia, PA July 1985 - June 1990 Associate Professor, Theory Group University of Pennsylvania, Philadelphia, PA January 1983 - June 1985 Assistant Professor, Theoretical Particle Physics Rockefeller University, New York, NY Sept. 1980 - Dec. 1982 Member, School of Natural Sciences The Institute for Advanced Study Princeton, New Jersey September 1978 - June 1980 Research Associate, High Energy Physics Brandeis University, Boston, Massachusetts VISITING POSITIONS: July 1981 - September 1981 Scientific Associate, Theory Group, CERN Geneva, Switzerland October 1988 - October 1990 Adjunct Professor, Theoretical Particle Physics Rockefeller University, New York, NY October 1992 - October 1993 Scientific Associate, Theory Group, CERN Geneva, Switzerland December 1994- January 1995 Scientific Associate, Theory Group, CERN Geneva, Switzerland September, 1996- May, 1997 Member, School of Natural Sciences The Institute for Advanced Study Princeton, New Jersey September, 1997-August 2001
    [Show full text]
  • The B-L Phase Transition – Implications for Cosmology
    DESY-THESIS-2012-039 Juli 2012 The B L Phase Transition − Implications for Cosmology and Neutrinos Dissertation zur Erlangung des Doktorgrades des Departments Physik der Universitt Hamburg vorgelegt von Kai Schmitz arXiv:1307.3887v1 [hep-ph] 15 Jul 2013 aus Berlin Hamburg 2012 Gutachter der Dissertation: Prof. Dr. Wilfried Buchm¨uller Prof. Dr. Mark Hindmarsh Prof. Dr. G¨unter Sigl Gutachter der Disputation: Prof. Dr. Wilfried Buchm¨uller Prof. Dr. Jan Louis Datum der Disputation: 9. Juli 2011 Vorsitzender des Prfungsausschusses: Prof. Dr. Georg Steinbr¨uck Vorsitzender des Promotionsausschusses: Prof. Dr. Peter Hauschildt Dekan der Fakultt fr Mathematik, Informatik und Naturwissenschaften: Prof. Dr. Heinrich Graener Abstract We investigate the possibility that the hot thermal phase of the early universe is ignited in consequence of the B L phase transition, which represents the cosmological realization of − the spontaneous breaking of the Abelian gauge symmetry associated with B L, the differ- − ence between baryon number B and lepton number L. Prior to the B L phase transition, − the universe experiences a stage of hybrid inflation. Towards the end of inflation, the false vacuum of unbroken B L symmetry decays, which entails tachyonic preheating as well as − the production of cosmic strings. Observational constraints on this scenario require the B L − phase transition to take place at the scale of grand unification. The dynamics of the B L − breaking Higgs field and the B L gauge degrees of freedom, in combination with thermal pro- − cesses, generate an abundance of heavy (s)neutrinos. These (s)neutrinos decay into radiation, thereby reheating the universe, generating the baryon asymmetry of the universe and setting the stage for the thermal production of gravitinos.
    [Show full text]
  • Black Holes Stimulate Higgs Vacuum Decay Supervisor: Author: Paul Steinhardt Luca Victor Iliesiu Collaborator: Ana Roxana Pop Abstract
    Princeton University Department of Mathematics Certificate in Applied and Computational Mathematics | Final Paper Black Holes Stimulate Higgs Vacuum Decay Supervisor: Author: Paul Steinhardt Luca Victor Iliesiu Collaborator: Ana Roxana Pop Abstract In this paper, we provide evidence that black holes with masses around ∼ 0:1 kg severely enhance the Higgs vacuum decay rate to the true vacuum. Results from the LHC show that in flat space the lifetime of the Higgs vacuum is much longer than the estimated age of the universe. However, assuming the standard model, we find that a single primordial black hole that evaporates down to a mass of mBH ∼ 0:03 kg − 0:17 kg, could make the transition to the true vacuum almost instantaneous. The enhancement of the decay rate is caused primarily by metric distortions around the black hole, as we show that thermal and backreaction effects are negligible. Our paper thus places tension between the standard model and cosmological models which predict the existence of primordial black holes in our past lightcone. May 11, 2015 Contents 1 Introduction 1 2 The Higgs Instability in Flat Space 3 3 The Fubini Instanton and Primordial Black Holes 5 4 Metric Backreaction and Thermal Effects 8 5 Discussion 9 1 Introduction The recent results at the LHC not only confirm our understanding of the standard model, with the discovery of the Higgs boson, but also give an indication about the stability of our vacuum. If the standard model is valid up to energies greater than 1012GeV, the observed masses of the Higgs boson and the top-quark indicate that the vacuum is meta-stable and that it will transition to a lower energy state in the future.
    [Show full text]
  • The Inflation Debate
    Author Bio Text until an ‘end nested style character’ (Com- mand+3) xxxx xxxx xx xxxxx xxxxx xxxx xxxxxx xxxxxx xxx xx xxxxxxxxxx xxxx xxxxxxxxxx xxxxxx xxxxxxxx xxxxxxxx. COSMOLOGY Is the theory at the heart of modern cosmology deeply flawed? By Paul J. Steinhardt 36 Scientific American, April 2011 Illustrations by Malcolm Godwin © 2011 Scientific American Deflating cosmology? Cosmologists are reconsidering whether the universe really went through an intense growth spurt (yellowish region) shortly after the big bang. April 2011, ScientificAmerican.com 37 © 2011 Scientific American Paul J. Steinhardt is director of the Princeton Center for Theo- retical Science at Princeton University. He is a member of the Na- tional Academy of Sciences and received the P.A.M. Dirac Medal from the International Center for Theoretical Physics in 2002 for his contributions to inflationary theory. Steinhardt is also known for postulating a new state of matter known as quasicrystals. hirty years ago alan h. guth, then a struggling physics two cases are not equally well known: the postdoc at the Stanford Linear Accelerator Center, gave a evidence favoring inflation is familiar to series of seminars in which he introduced “inflation” a broad range of physicists, astrophysi- into the lexicon of cosmology. The term refers to a brief cists and science aficionados. Surpris- burst of hyperaccelerated expansion that, he argued, ingly few seem to follow the case against may have occurred during the first instants after the big inflation except for a small group of us bang. One of these seminars took place at Harvard Uni- who have been quietly striving to ad- versity, where I myself was a postdoc.
    [Show full text]
  • December 2020
    The Newsletter of Westchester Amateur Astronomers December 2020 An eyepiece view of the Double Cluster by Steve Bellavia. SERVING THE ASTRONOMY COMMUNITY SINCE 1986 1 Westchester Amateur Astronomers SkyWAAtch December 2020 WAA December 2020 Meeting WAA January 2021 Meeting Friday, December 4th at 7:30 pm Friday, January 15th at 7:30 pm On-line via Zoom On-line via Zoom Intensity Mapping of the Large Scale Microquasars Structure of Matter Diana Hannikainen, Ph.D. Paul O’Connor, Ph.D. Observing Editor Sky & Telescope Brookhaven National Laboratory Call: 1-877-456-5778 (toll free) for announcements, Paul O’Connor is Senior Scientist at Brookhaven's weather cancellations, or questions. Also, don’t for- Instrumentation Division. He was a member of the get to visit the WAA website. team that built the CCD camera for the Large Synop- tic Survey Telescope (now the Vera Rubin Telescope) Starway to Heaven in Chile, the largest digital camera in the world. He is Ward Pound Ridge Reservation, currently working on designing radio telescope in- Cross River, NY strumentation for improved mapping of the 21-cm HI (neutral hydrogen) line, with the goal of creating a 3- Our next club star party will be in March 2021. Mem- dimensional map of the matter density of the uni- bers are invited to view at Ward Pound Ridge verse. This will be key to understanding the formation Reservation on clear nights, provided they notify the and evolution of galaxies and the behavior of the park in advance and bring their ID cards. cosmic web. New Members Pre-lecture socializing with fellow WAA members and guests begins at 7:00 pm! Uziel Crescenzi Bronx Rodrigo Morales Hartsdale WAA Members: Contribute to the Newsletter! Francesca Varga Pleasantville Send articles, photos, or observations to Carlos Vegerano Bronx [email protected] Renewing Members SkyWAAtch © Westchester Amateur Astronomers, Inc.
    [Show full text]
  • Inflation After False Vacuum Decay: Observational Prospects After Planck
    PHYSICAL REVIEW D 91, 083527 (2015) Inflation after false vacuum decay: Observational prospects after Planck † ‡ Raphael Bousso,1,2,* Daniel Harlow,3, and Leonardo Senatore4,5,6, 1Center for Theoretical Physics and Department of Physics, University of California, Berkeley, California 94720, USA 2Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 3Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08540, USA 4Stanford Institute for Theoretical Physics, Stanford University, Stanford, California 94306, USA 5Kavli Institute for Particle Astrophysics and Cosmology, Stanford University and SLAC, Menlo Park, California 94025, USA 6CERN, Theory Division, 1211 Geneva 23, Switzerland (Received 1 December 2014; published 22 April 2015) We assess two potential signals of the formation of our universe by the decay of a false vacuum. Negative spatial curvature is one possibility, but the window for its detection is now small. However, another possible signal is a suppression of the cosmic microwave background (CMB) power spectrum at large angles. This arises from the steepening of the effective potential as it interpolates between a flat inflationary plateau and the high barrier separating us from our parent vacuum. We demonstrate that these two effects can be parametrically separated in angular scale. Observationally, the steepening effect appears to be excluded at large l; but it remains consistent with the slight lack of power below l ≈ 30 found by the WMAP and Planck collaborations. We give two simple models which improve the fit to the Planck data; one with observable curvature and one without. Despite cosmic variance, we argue that future CMB polarization and most importantly large-scale structure observations should be able to corroborate the Planck anomaly if it is real.
    [Show full text]
  • PEOPLE Dirac Prize Is Awarded to Inflation Pioneers
    PEOPLE Dirac prize is awarded to inflation pioneers Alan Guth of MIT. (Donna Coveney MIT.) Andrei Linde of Stanford. Paul Steinhardt of Princeton. TheAbdus Salam International Centre for confronting Big Bang cosmology. Difficulties perturbations that can seed galaxy formation Theoretical Physics (ICTP) in Trieste, Italy, has with the original inflationary model were rec­ and explain the fluctuations in the cosmic awarded this year's Dirac Medal and Prize to ognized from the start, and were overcome microwave background. Alan Guth of MIT, Andrei Linde of Stanford with the introduction of "new" inflation by Although not yet firmly established, the idea and Paul Steinhardt of Princeton for the Linde, Steinhardt and Andreas Albrecht, a of inflation has had notable observational development of cosmological inflation. While student of Steinhardt's. Linde went on to successes, and has become the paradigm for the possibility of an exponential expansion of propose other promising versions of inflation­ fundamental studies in cosmology. Its great­ the early universe had been noted before, it ary theory, such as chaotic inflation. Guth and est success has been in accounting for the was Guth who first realized that inflation Steinhardt, among others, showed that infla­ existence of inhomogeneities in the universe would solve some of the major problems tion leads to a spectrum of density and predicting their spectrum. Gunnar Ingelman (left) and Torbjorn Sjdstrand attended a symposium at Lund University, Sweden, in June to celebrate the 25th anniversary of the Lund model and to honour one of Takashi Kohiriki (right) presented its pioneers, Bo Andersson, who died earlier this year (CERN Courier May p40).
    [Show full text]
  • Task Force on Cosmic Microwave Background Research
    Task Force On Cosmic Microwave Background Research Final Report July 11, 2005 -1- MEMBERS OF THE CMB TASK FORCE James Bock Caltech/JPL Sarah Church Stanford University Mark Devlin University of Pennsylvania Gary Hinshaw NASA/GSFC Andrew Lange Caltech Adrian Lee University of California at Berkeley/LBNL Lyman Page Princeton University Bruce Partridge Haverford College John Ruhl Case Western Reserve University Max Tegmark Massachusetts Institute of Technology Peter Timbie University of Wisconsin Rainer Weiss (chair) Massachusetts Institute of Technology Bruce Winstein University of Chicago Matias Zaldarriaga Harvard University AGENCY OBSERVERS Beverly Berger National Science Foundation Vladimir Papitashvili National Science Foundation Michael Salamon NASA/HDQTS Nigel Sharp National Science Foundation Kathy Turner US Department of Energy -2- Table of Contents Executive Summary ...........................................................................................4 1 Outline of Report ................................................................................................8 sidebar “Some History and Perspective..............................................................10 2 Cosmology and Inflation ..................................................................................11 sidebar “Direct Measurement of Primeval Gravitational Waves” ....................18 3 Theory of CMB Polarization and Gravitational Waves ....................................19 4 Astrophysical Disturbances in Measuring the CMB Polarization: Gravitational
    [Show full text]