Research on Gravitation and Quantized Fields (Physics)

这项研究涉及量子理论和引力之间关系的几个方面，特别是那些与理解宇宙起源和演化有关的方面。这项工作是寻求更好地理解引力对量子系统的影响和引力的量子本质的一系列调查的一部分。具体研究课题包括：(1)宇宙学中尚未解决的基本问题--宇宙常数问题。这个问题将在可能的动力学机制的背景下进行研究，该机制迫使宇宙“常量”的值衰变。(2)经典能量条件的量子违反(例如，产生负的能量密度)及其对引力的影响。这将研究人们可以在多大程度上用量子物质产生奇异的引力场，并避免经典广义相对论的奇点。(3)半经典近似对量子引力的适用范围。这对于理解宇宙的早期历史和指导更完整的量子引力理论的发展都是重要的。(4)量子场论的替代方法。这是对研究量子过程的新方法的探索，特别是在引力存在的情况下。

This research deals with several aspects of the relationship between quantum theory and gravitation, especially those which are relevant to understanding the origin and evolution of the universe. This work is part of a line of enquiry that seeks to better understand the effects of gravitation on quantum systems and the quantum nature of gravity. The specific research topics include: (1) The problem of the cosmological constant, a fundamental, unsolved problem in cosmology. The problem will be studied in the context of possible dynamical mechanism that force the value of the cosmological "constant" to decay. (2) Quantum violations of classical energy conditions (e.g. generation of negative energy densities) and their effects upon gravitation. This will study the extent to which one can produce exotic gravitational fields with quantum matter and avoid the singularities of classical general relativity. (3) The limits of validity of the semiclassical approximation to quantum gravity. This is of importance both for understanding the early history of the universe and for guiding the development of a more complete quantum gravity theory. (4) Alternative approaches to quantum field theory. This is a search for new ways of studying quantum processes, especially in the presence of gravity.