Research on Quantum Fluctuation Phenomena and Gravity

这笔拨款支持对能量密度和压强的大量子涨落及其物理效应的研究。PI和他的合作者最近的研究表明，这种波动比之前认为的要少得多。巨大的压力波动可能会以可以观察到的速度推动量子粒子(如电子)越过势垒，并产生技术后果。大的能量密度涨落会导致早期宇宙中新阶段气泡的成核，这可能会在宇宙的演化中发挥作用。这些波动还会改变引力场，影响光线的传播。这是量子引力的一种效应，它的研究将有助于阐明量子理论和相对论之间的关系，这是理论物理中尚未解决的问题之一。该项目还将研究涉及非线性光学的量子引力的模拟模型，其结果可能会导致对光学以及量子引力的更深层次理解。本科生和研究生都将参与这项研究。该项目的一些结果应该有助于向学生阐明量子理论和相对论的微妙概念。这项研究将集中在量子应力张量算符的时空平均的概率分布上。过去关于这个主题的工作只集中在时间平均上。这里还将包括空间平均的影响。还将研究概率分布在几个系统中的应用。其中包括应力张量涨落对提高量子势垒穿透率和增加假真空衰减率的影响，这两种效应都可能有重要的应用。应力张量涨落在驱动时空几何涨落中的作用也将被研究。几何形状起伏的一个影响是光锥起伏。可以使用的一种方法是模拟模型，在该模型中，非线性介质中电场的平方真空起伏引起光速起伏。这种效应可以为量子引力效应提供有用的见解，而且它本身就很有趣，可能会在实验上观察到。我们还将研究应力张量涨落在宇宙学模型中的作用。

This grant supports investigation on large quantum fluctuations of energy density and pressure and their physical effects. Recent work by the PI and his collaborators has shown that these fluctuations are much less rare than previously thought. Large pressure fluctuations may be able to push quantum particles, such as electrons, over potential barriers at a rate which might be observable and have technological consequences. Large energy density fluctuations can cause the nucleation of bubbles of a new phase in the early universe, which could play a role in the evolution of the universe. These fluctuations can also alter the gravitational field and influence the propagation of light rays. This is an effect of quantum gravity, and its study will help to elucidate the relation between quantum theory and relativity theory, which is one of the unsolved problems of theoretical physics. The project will also study analog models for quantum gravity involving nonlinear optics, and the results may lead to a deeper understanding of optics, as well as quantum gravity. Both undergraduate and graduate students will participate in the research. Some of the results of the project should help to illustrate subtle concepts of quantum theory and relativity to students.This research will focus on the probability distributions for spacetime averages of quantum stress tensor operators. Past work on this topic has focused only on time averages. Here the effects of spatial averaging will also be included. The applications of the probability distributions to several systems will also be investigated. These include the effects of stress tensor fluctuations in enhancing the rates for quantum barrier penetration and in increasing the rates of false vacuum decay, both of which could have significant applications. The role of stress tensor fluctuations in driving spacetime geometry fluctuations will also be studied. One effect of geometry fluctuations will be light cone fluctuations. One approach to be used is an analog model in which squared electric field vacuum fluctuations in a nonlinear dielectric cause light speed fluctuations. This effect can give useful insights into quantum gravity effects, and is of interest in its own right and might be experimentally observable. The role of stress tensor fluctuation in cosmological models will also be studied.