Presentation of the Second Big Challenge Symposium - The Big Challenge of Cosmological Understanding: Gravitation, Dark Matter and Dark Energy. Towards New Scenarios
Christian Corda
备注：
To appear in the AIP Proceedings of the 8th International Conference of Numerical Analysis and Applied Mathematics, Hotel Rodos Palace, Rhodes, Greece, 1925 September 2010
This Symposium is devoted to the Memory of Lev Kofman, June-17-1957-November-12-2009.
The accelerated expansion of the Universe, which is today observed, shows that cosmological dynamics is dominated by the so-called Dark Energy field which provides a large negative pressure. This is the standard picture, in which such new ingredient is considered as a source of the right hand side of the field equations. It should be some form of non-clustered non-zero vacuum energy which, together with the clustered Dark Matter, drives the global dynamics. This is the so-called "concordance model" (ACDM) which gives, in agreement with the Cosmic Microwave Background Radiation (CMBR), dim Lyman Limit Systems (LLS) and type la supernovae (SNeIa) data, a good framework to understand the today observed Universe. However, it presents several shortcomings as the well known "coincidence" and "cosmological constant" problems . An alternative approach is to have a better understanding of the energy concept in General Relativity and also to change the left hand side of the field equations, and check if observed cosmic dynamics can be achieved by extending general relativity. In this different context, it is not required to search candidates for Dark Energy and Dark Matter, which till now have not been found. Rather, one can only stand on the "observed" ingredients: curvature and baryon matter, to account for the observations. Considering this point of view, one can think of that gravity is not scale-invariant. The goal of this Symposium is to obtain a tapestry of the present status of theory and observations concerning Gravitation and Dark Universe.
Matters of Gravity, The Newsletter of the Topical Group on Gravitation of the American Physical Society, Volume 37, Winter 2011
GGR新闻：在加利福尼亚州阿纳海姆举行的APS会议上的GGR项目我们听说...，作者：David Garfinkle 100 years ago，作者：David Garfinkle Research Briefs：End of the Gregory-Laflamme Instability，作者：Gary Horowitz Conference Reports：Aparrasekhar Symposium，作者：David Garfinkle
Matters of Gravity, The Newsletter of the Topical Group in Gravitation of the American Physical Society, Volume 33, Winter 2009
GGR新闻：在丹佛举行的APS会议上，大卫·加芬克尔主持了GGR节目，我们听说...，作者：David Garfinkle o 400年前，作者：David Garfinkle会议报告：o第24届德克萨斯州相对论天体物理学研讨会，作者：Scott Hughes o Loop量子宇宙学研讨会，作者：Parampreet Singh
Matters of Gravity, The Newsletter of the Topical Group in Gravitation of the American Physical Society, Volume 32, Fall 2008
GGR新闻：- Remembering Wheeler，by Jim Isenberg; Research Briefs：- A Brief Summary of the WMAP 5 Results，by Lyman Page; - Science with LIGO，by Maria Alessandra Papa; Conference Reports：- 7th LISA Symposium，by Edward K.第四届墨西哥湾沿岸重力会议，Lior Burko
Matters of Gravity, the newsletter of the APS Topical Group on Gravitation
研究简介：宇宙微波背景各向异性实验，作者Sean Carroll LISA项目更新，作者Bill Folkner关于r模式不稳定性的更新，作者Nils Andersson实验室实验：来自MG 9的新闻，作者Riley Newman LIGO探测器调试进展，作者Stan Whitcomb在TAMA 300上获取的160小时数据，作者Seiji Kawamura会议报告：Kipfest，by Richard Price Third Capra meeting，by Eric Poisson GR at the XIIIth Congress on数学物理，by Abhay Ashtekar 3rd International LISA Symposium，by Curt Cutler
A Striking Property of the Gravitational Hamiltonian
{ \sl在渐近平坦的背景下考虑了2+1维引力与物质耦合的哈密顿框架（满足正能量条件）。它表明，系统的总能量是非负的，零的当且仅当时空是（整体）闵可夫斯基。此外，与通常场论的经验相反，哈密顿量是} { \rm有界的}。这是一个真正的非微扰结果。{ \sl在类空Killing场存在的情况下，3+1维真空广义相对论等价于2+1维广义相对论耦合到某些物质场。因此，我们的表达式特别提供了3+1维空间中具有类空对称性的引力波的单位长度（沿对称方向）能量公式。一个特殊的情况是柱面波有两个超曲面正交，类空的Killing场。在这种情况下，我们的表达式以非多项式的方式与“c-能量”相关。而在弱场限制，这两个同意，在强场制度，他们显着不同。通过构造，我们的表达式得到了完整理论中时间平移的生成元，因此表示了引力场中的物理能量。} \footnote{$^1$}{This is a detailed account of the results presented in the Brill-Misner symposium at the University of Maryland in May1993}
On Circular Orbits in Einstein's Theory of Gravitation
这份预印本是著名天体物理学家萨缪尔·卡普兰（Samuil Kaplan，1921-1978）的论文“O krugovykh orbitakh v teorii tyagoteniya Einsteina（On circular orbits in Einstein's theory of gravitation）"的英文译本，该论文于1949年发表在《实验与理论物理学杂志》（Journal of Experimental and Theoretical Physics，Vol. 19，No. 10，pp. 951-952）在俄罗斯。由于缺乏这样的翻译，这篇重要的1又1/3页的论文仍然无法被广泛的专家和学生所理解。本文是萨缪尔·卡普兰的第一篇科学论文，也是该领域的开创性工作。本报告的目的是向广义相对论、相对论天体物理学和科学史领域的广泛专家提供这篇文章，并在作者诞辰100周年之际向他表示敬意。
