Living Reviews in Relativity最新文献

{"title":"Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors","authors":"Jonathan R. Gair,&nbsp;Michele Vallisneri,&nbsp;Shane L. Larson,&nbsp;John G. Baker","doi":"10.12942/lrr-2013-7","DOIUrl":"https://doi.org/10.12942/lrr-2013-7","url":null,"abstract":"<p>We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ～ 10^?5 ? 1 Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional gravitational fields other than the metric; the number and tensorial nature of gravitational-wave polarization states; the velocity of propagation of gravitational waves; the binding energy and gravitational-wave radiation of binaries, and therefore the time evolution of binary inspirals; the strength and shape of the waves emitted from binary mergers and ringdowns; the true nature of astrophysical black holes; and much more. The strength of this science alone calls for the swift implementation of a space-based detector; the remarkable richness of astrophysics, astronomy, and cosmology in the low-frequency gravitational-wave band make the case even stronger.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"16 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2013-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2013-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4513495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmology and Fundamental Physics with the Euclid Satellite","authors":"Luca Amendola,&nbsp;Stephen Appleby,&nbsp;David Bacon,&nbsp;Tessa Baker,&nbsp;Marco Baldi,&nbsp;Nicola Bartolo,&nbsp;Alain Blanchard,&nbsp;Camille Bonvin,&nbsp;Stefano Borgani,&nbsp;Enzo Branchini,&nbsp;Clare Burrage,&nbsp;Stefano Camera,&nbsp;Carmelita Carbone,&nbsp;Luciano Casarini,&nbsp;Mark Cropper,&nbsp;Claudia de Rham,&nbsp;Cinzia Di Porto,&nbsp;Anne Ealet,&nbsp;Pedro G. Ferreira,&nbsp;Fabio Finelli,&nbsp;Juan García-Bellido,&nbsp;Tommaso Giannantonio,&nbsp;Luigi Guzzo,&nbsp;Alan Heavens,&nbsp;Lavinia Heisenberg,&nbsp;Catherine Heymans,&nbsp;Henk Hoekstra,&nbsp;Lukas Hollenstein,&nbsp;Rory Holmes,&nbsp;Ole Horst,&nbsp;Knud Jahnke,&nbsp;Thomas D. Kitching,&nbsp;Tomi Koivisto,&nbsp;Martin Kunz,&nbsp;Giuseppe La Vacca,&nbsp;Marisa March,&nbsp;Elisabetta Majerotto,&nbsp;Katarina Markovic,&nbsp;David Marsh,&nbsp;Federico Marulli,&nbsp;Richard Massey,&nbsp;Yannick Mellier,&nbsp;David F. Mota,&nbsp;Nelson J. Nunes,&nbsp;Will Percival,&nbsp;Valeria Pettorino,&nbsp;Cristiano Porciani,&nbsp;Claudia Quercellini,&nbsp;Justin Read,&nbsp;Massimiliano Rinaldi,&nbsp;Domenico Sapone,&nbsp;Roberto Scaramella,&nbsp;Constantinos Skordis,&nbsp;Fergus Simpson,&nbsp;Andy Taylor,&nbsp;Shaun Thomas,&nbsp;Roberto Trotta,&nbsp;Licia Verde,&nbsp;Filippo Vernizzi,&nbsp;Adrian Vollmer,&nbsp;Yun Wang,&nbsp;Jochen Weller,&nbsp;Tom Zlosnik,&nbsp;The Euclid Theory Working Group","doi":"10.12942/lrr-2013-6","DOIUrl":"https://doi.org/10.12942/lrr-2013-6","url":null,"abstract":"<p>Euclid is a European Space Agency medium-class mission selected for launch in 2019 within the Cosmic Vision 2015–2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky.</p><p>Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis.</p><p>This review has been planned and carried out within Euclid’s Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"16 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2013-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2013-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4446042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum-Spacetime Phenomenology","authors":"Giovanni Amelino-Camelia","doi":"10.12942/lrr-2013-5","DOIUrl":"https://doi.org/10.12942/lrr-2013-5","url":null,"abstract":"<p>I review the current status of phenomenological programs inspired by quantum-spacetime research. I stress in particular the significance of results establishing that certain data analyses provide sensitivity to effects introduced genuinely at the Planck scale. My main focus is on phenomenological programs that affect the directions taken by studies of quantum-spacetime theories.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"16 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2013-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2013-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4497964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relativistic Binaries in Globular Clusters","authors":"Matthew J. Benacquista,&nbsp;Jonathan M. B. Downing","doi":"10.12942/lrr-2013-4","DOIUrl":"https://doi.org/10.12942/lrr-2013-4","url":null,"abstract":"<p>Galactic globular clusters are old, dense star systems typically containing 10⁴–10⁶ stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct <i>N</i>-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"16 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2013-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2013-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4171392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Spin-Foam Approach to Quantum Gravity","authors":"Alejandro Perez","doi":"10.12942/lrr-2013-3","DOIUrl":"https://doi.org/10.12942/lrr-2013-3","url":null,"abstract":"This article reviews the present status of the spin-foam approach to the quantization of gravity. Special attention is payed to the pedagogical presentation of the recently-introduced new models for four-dimensional quantum gravity. The models are motivated by a suitable implementation of the path integral quantization of the Plebanski formulation of gravity on a simplicial regularization. The article also includes a self-contained treatment of 2+1 gravity. The simple nature of the latter provides the basis and a perspective for the analysis of both conceptual and technical issues that remain open in four dimensions.","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"16 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2013-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2013-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4565110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Minimal Length Scale Scenarios for Quantum Gravity","authors":"Sabine Hossenfelder","doi":"10.12942/lrr-2013-2","DOIUrl":"https://doi.org/10.12942/lrr-2013-2","url":null,"abstract":"<p>We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"16 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2013-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2013-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5112913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Foundations of Black Hole Accretion Disk Theory","authors":"Marek A. Abramowicz,&nbsp;P. Chris Fragile","doi":"10.12942/lrr-2013-1","DOIUrl":"https://doi.org/10.12942/lrr-2013-1","url":null,"abstract":"<p>This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks), Shakura-Sunyaev (thin) disks, slim disks, and advection-dominated accretion flows (ADAFs). After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs).</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"16 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2013-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2013-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4568195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Kerr/CFT Correspondence and its Extensions","authors":"Geoffrey Compère","doi":"10.12942/lrr-2012-11","DOIUrl":"https://doi.org/10.12942/lrr-2012-11","url":null,"abstract":"<p>We present a first-principles derivation of the main results of the Kerr/CFT correspondence and its extensions using only tools from gravity and quantum field theory, filling a few gaps in the literature when necessary. Firstly, we review properties of extremal black holes that imply, according to semi-classical quantization rules, that their near-horizon quantum states form a centrally-extended representation of the one-dimensional conformal group. This motivates the conjecture that the extremal Kerr and Reissner-Nordstr?m black holes are dual to the chiral limit of a two-dimensional CFT. We also motivate the existence of an <i>SL</i>(2, ?) family of two-dimensional CFTs, which describe in their chiral limit the extremal Kerr-Newman black hole. We present generalizations in anti-de Sitter spacetime and discuss other matter-coupling and higher-derivative corrections. Secondly, we show how a near-chiral limit of these CFTs reproduces the dynamics of near-superradiant probes around near-extremal black holes in the semi-classical limit. Thirdly, we review how the hidden conformal symmetries of asymptotically-flat black holes away from extremality, combined with their properties at extremality, allow for a microscopic accounting of the entropy of non-extremal asymptotically-flat rotating or charged black holes. We conclude with a list of open problems.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"15 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2012-11","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5174980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modified Newtonian Dynamics (MOND): Observational Phenomenology and Relativistic Extensions","authors":"Benoît Famaey,&nbsp;Stacy S. McGaugh","doi":"10.12942/lrr-2012-10","DOIUrl":"https://doi.org/10.12942/lrr-2012-10","url":null,"abstract":"<p>A wealth of astronomical data indicate the presence of mass discrepancies in the Universe. The motions observed in a variety of classes of extragalactic systems exceed what can be explained by the mass visible in stars and gas. Either (i) there is a vast amount of unseen mass in some novel form — dark matter — or (ii) the data indicate a breakdown of our understanding of dynamics on the relevant scales, or (iii) both. Here, we first review a few outstanding challenges for the dark matter interpretation of mass discrepancies in galaxies, purely based on observations and independently of any alternative theoretical framework. We then show that many of these puzzling observations are predicted by one single relation — Milgrom’s law — involving an acceleration constant <i>a</i>₀ (or a characteristic surface density Σ_? = <i>a</i>₀/<i>G</i>) on the order of the square-root of the cosmological constant in natural units. This relation can at present most easily be interpreted as the effect of a single universal force law resulting from a modification of Newtonian dynamics (MOND) on galactic scales. We exhaustively review the current observational successes and problems of this alternative paradigm at all astrophysical scales, and summarize the various theoretical attempts (TeVeS, GEA, BIMOND, and others) made to effectively embed this modification of Newtonian dynamics within a relativistic theory of gravity.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"15 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2012-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2012-10","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4320063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continuum and Discrete Initial-Boundary Value Problems and Einstein’s Field Equations","authors":"Olivier Sarbach,&nbsp;Manuel Tiglio","doi":"10.12942/lrr-2012-9","DOIUrl":"https://doi.org/10.12942/lrr-2012-9","url":null,"abstract":"<p>Many evolution problems in physics are described by partial differential equations on an infinite domain; therefore, one is interested in the solutions to such problems for a given initial dataset. A prominent example is the binary black-hole problem within Einstein’s theory of gravitation, in which one computes the gravitational radiation emitted from the inspiral of the two black holes, merger and ringdown. Powerful mathematical tools can be used to establish qualitative statements about the solutions, such as their existence, uniqueness, continuous dependence on the initial data, or their asymptotic behavior over large time scales. However, one is often interested in computing the solution itself, and unless the partial differential equation is very simple, or the initial data possesses a high degree of symmetry, this computation requires approximation by numerical discretization. When solving such discrete problems on a machine, one is faced with a finite limit to computational resources, which leads to the replacement of the infinite continuum domain with a finite computer grid. This, in turn, leads to a discrete initial-boundary value problem. The hope is to recover, with high accuracy, the exact solution in the limit where the grid spacing converges to zero with the boundary being pushed to infinity.</p><p>The goal of this article is to review some of the theory necessary to understand the continuum and discrete initial boundary-value problems arising from hyperbolic partial differential equations and to discuss its applications to numerical relativity; in particular, we present well-posed initial and initial-boundary value formulations of Einstein’s equations, and we discuss multi-domain high-order finite difference and spectral methods to solve them.</p>","PeriodicalId":686,"journal":{"name":"Living Reviews in Relativity","volume":"15 1","pages":""},"PeriodicalIF":40.6,"publicationDate":"2012-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.12942/lrr-2012-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5031032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}