Quantum Field Theory and Cosmology

量子场论和宇宙学

• 批准号: 0244714
• 负责人: Richard Woodard
• 金额: $ 9万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-15 至 2007-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0244714&HistoricalAwards=false
• 关键词: Quantum; Field; Theory; Cosmology

The project involves a number of areas of collaborative research with N. Tsamis (U. of Crete), T. Prokopec (U. of Heidelberg), and the PI's graduate students in the general area of quantum field theoretic effects in cosmology . These include: (1) Comparing standard cosmological perturbation approximations with the exact solution recently obtained by the PI and Tsamis; (2) A method to calculate the effect of quantum gravity on inflation; (3) Developing a model in which the observed excess of matter over anti-matter is generated during inflation. (4) Computing what happens to the vacuum polarization induced by charged, massless scalar particles after the end of inflation; (5) Investigating whether a very slightly unstable, alternate theory of gravitation can be constructed which explains the motions of cosmological objects without the need for dark matter. (6) Expressing the vacuum polarization of charged massless scalar particles in terms of the natural geometrical objects during inflation; (7) Developing an improved formalism for computing quantum gravitational effects in a locally de Sitter-cosmology background. Problem (1) is relevant to the precision measurements of the cosmic microwave anisotropy by the WMAP satellite and the various missions planned for the future. Standard approximation techniques are almost certainly sufficient to compute the primordial spectrum from simple models of inflation but the exact result obtained by the PI and Tsamis may be very useful if an exotic model pertains. A successful outcome for problem (2) would completely change the paradigm of inflationary cosmology, resolving two of its major problems (why was the initial state homogeneous enough to begin inflating? and why is the observed cosmological constant so small?) and transforming it into a predictive theory. A successful outcome for problem (3) would resolve the long-standing conundrum that inflation tends to wipe out the excess of matter over anti-matter. Problem (4) should settle the issue of whether or not inflation provided the small but cosmological scale magnetic fields that served as the seeds of the fields we observe in present-day galaxies and galactic clusters. Problem (5) represents the last realistic hope for explaining cosmological motions using an alternate theory of gravitation rather than dark matter. Problems (6-7)represent incremental advances in formalism and good exercises for beginning graduate students.

该项目涉及与N. Tsamis（U. of Crete），T.普罗克什（U.的海德堡），和PI的研究生在宇宙学的量子场论效应的一般领域。其中包括：（1）将标准宇宙学微扰近似与PI和Tsamis最近获得的精确解进行比较;（2）计算量子引力对暴胀的影响的方法;（3）建立一个模型，在该模型中，观测到的物质超过反物质是在暴胀过程中产生的。(4)计算在暴胀结束后，带电的无质量标量粒子引起的真空极化会发生什么;（5）研究是否可以建立一个非常不稳定的替代引力理论，解释宇宙学物体的运动，而不需要暗物质。(6)用自然几何对象表示暴胀过程中带电无质量标量粒子的真空极化;（7）发展了一种改进的计算局部de Sitter宇宙学背景下量子引力效应的形式。 问题（1）与WMAP卫星对宇宙微波各向异性的精确测量和未来计划的各种任务有关。标准近似技术几乎肯定足以从简单的暴胀模型计算原始谱，但如果有一个奇异的模型，PI和Tsamis获得的精确结果可能非常有用。问题（2）的成功结果将彻底改变暴胀宇宙学的范式，解决它的两个主要问题（为什么初始状态均匀到足以开始暴胀？为什么观测到的宇宙常数如此之小？）并将其转化为预测理论。问题（3）的成功结果将解决长期存在的难题，即暴胀倾向于消除物质对反物质的过剩。问题（4）应该解决这样一个问题：暴胀是否提供了宇宙尺度的小磁场，这些磁场是我们在今天的星系和星系团中观察到的场的种子。问题（5）代表了用另一种引力理论而不是暗物质理论来解释宇宙运动的最后现实希望。问题（6-7）代表了形式主义的渐进式进步，也是初学研究生的好练习。