Quantum Gravity and Relativistic Astrophysics

量子引力和相对论天体物理学

• 批准号: 0514282
• 负责人: Richard Price
• 金额: $ 18.83万
• 依托单位: The University of Texas at Brownsville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-20 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0514282&HistoricalAwards=false
• 关键词: Quantum; Gravity; Relativistic; Astrophysics

This project contains two components: (1) The astrophysical research focuses on a program to produce approximate gravitational waveforms to provide useful information to ongoing gravitational wave detection experiments on a faster time scale than that likely to be needed for an accurate numerical simulation. In their last few orbits of inspiral, and in their final plungeand merger, these binaries strongly curve spacetime and strongly emit gravitational waves. A complete understanding of this process, and of the gravitational waveforms produced, will require much further development of supercomputer evolution codes. The approach here is to use an approximation scheme for the gradual late-stage binary inspiral followed by supercomputer evolution for the final inward plunge and merger of the holes. The method exploits the fact that the spacetime of the gradual inspiral differs very little from that of a perfectly periodic binary. This gradual inspiral is therefore approximated by an exactly periodic orbit. These periodic orbits can be used to construct a quasiequilibrium sequence representing the gradual pre-plunge decrease in radius of the binary, and to give a good approximation to the corresponding gravitational waveform. (2) An outstanding problem in theoretical physics is how to reconcile the principles of quantum theory with those of general relativity. In general relativity, spacetime does not have any fixed structure which is not dynamical but governs dynamics from outside as an unmoved mover. On the other hand, quantum theory depends on such structures. This project views Einstein's theory as a model on which one can clarify how to quantize a system with no external structure without introducing an external structure. The first main theme here is that foliations can be viewed not as fixed elements but as free variables which help us to build phase space from spacetime foliation. The second main theme is more specific. A black hole is formed by a spherical collapse of quantum matter that produces quantum geometry without its own degrees of freedom will be studied. A mean geometry and its fluctuations will be determined, and a study will be made of how the radiation produced on this background differs from the thermal radiation fields. At present, relativistic gravitation is of crucial interest both at the frontier of astrophysicsand at the frontier of theoretical physics. This project contains research of both types. In addition to its broad impacts on the two frontiers of gravitational physics, this project will also provide broad theoretical training to postdoctoral researchers and students.

该项目包括两个组成部分：（1）天体物理研究的重点是一个程序，以产生近似的引力波形，以提供有用的信息，以更快的时间尺度上进行的引力波探测实验比可能需要一个精确的数值模拟。在它们最后的几个螺旋轨道中，以及在它们最后的俯冲和合并中，这些双星强烈地弯曲时空，并强烈地发射引力波。要完全了解这一过程以及产生的引力波形，还需要进一步开发超级计算机演化代码。这里的方法是使用一种近似方案，用于渐进的后期二元螺旋，然后是超级计算机进化，用于最终的向内俯冲和合并的洞。该方法利用了这样一个事实，即渐进螺旋的时空与完美周期双星的时空差别很小。因此，这种渐进的螺旋近似于一个精确的周期轨道。这些周期性轨道可以用来构造一个准平衡序列，表示双星半径逐渐下降，并给出一个很好的近似相应的引力波形。(2)理论物理学中一个突出的问题是如何使量子理论的原理与广义相对论的原理相协调。在广义相对论中，时空没有任何固定的结构，它不是动力学的，而是作为一个不动的运动者从外部控制着动力学。另一方面，量子理论依赖于这样的结构。本项目将爱因斯坦的理论视为一个模型，在这个模型上，人们可以阐明如何在不引入外部结构的情况下对没有外部结构的系统进行建模。这里的第一个主题是，叶理不能被看作是固定元素，而是自由变量，这有助于我们从时空叶理建立相空间。第二个主题更为具体。黑洞是由量子物质的球形坍缩形成的，它产生了没有自由度的量子几何。将确定平均几何形状及其波动，并研究在这种背景下产生的辐射与热辐射场的不同。目前，相对论引力在天体物理学和理论物理学的前沿都有着重要的意义。该项目包含这两种类型的研究。除了对引力物理学的两个前沿领域产生广泛影响外，该项目还将为博士后研究人员和学生提供广泛的理论培训。