Inflationary Cosmology, Cosmic String Models, and the Vilkovisky-DeWitt Formalism (Physics)

艾伦教授将发起一个研究万有引力和宇宙学的新项目。这将探索早期宇宙的两种不同模型，看看它们对今天的宇宙有何预测。“暴胀”模型令人信服地解释了我们当今宇宙的巨大尺寸和均匀性。他将在这个模型中研究原始引力波的产生。为此，他将解决在德西特空间中处理引力子（传递引力的量子）时出现的一些困难，并了解量子效应如何影响该模型的物理稳定性。“宇宙弦”模型可以解释微波背景辐射中预期发生的温度波动。他正在构建一个“宇宙弦”环运动的计算机模拟，这种环被认为是模型中星系形成的原因。他将研究这些模型星系在太空中的分布，并将其与天文学家在天空中观察到的情况进行比较。最后，他将使用Vilkovisky和DeWitt发明的一种新的数学形式来计算量子效应。目的是了解这种方法的结果与目前使用的标准技术有何不同，并看看它们是否会改变暴胀模型中对引力波产生的预测。

Professor Allen will initiate a new program of researching in gravitation and cosmology. This will explore two different models of the early universe, to see what they predict about the universe today. The "inflationary" model convincingly accounts for the great size and uniformity of our present-day universe. He will study the production of primordial gravity-waves in this model. To do so, he will resolve some difficulties that have arisen in the treatment of gravitons (the quanta that transmit gravitational forces) in de Sitter space, and understand how quantum effects can influence the physical stability of this model. The "cosmic string" model can account for the temperature fluctuations expected to occur in the microwave background radiation. He is constructing a computer simulation of the motion of loops of "cosmic string" which are supposed to cause galaxies to form in the model. He will study the distribution of these model galaxies in space and compare it with what astronomers observe in the sky. Finally, he will use a new mathematical formalism invented by Vilkovisky and DeWitt for calculating quantum effects. The goal is to understand how the results of this method differ from standard techniques currently in use, and to see if they change the predictions about gravity-wave production in the inflationary model.