RUI: Impact of Negative Energy in General Relativity and Quantum Field Theory

该奖项支持一项研究项目，研究一种非常不寻常的能源形式的含义。这种所谓的“负能量”的存在是量子场论定律所允许的，量子场论描述了物质和能量在微观尺度上的行为。负能量也会产生排斥的引力效应。涉及负能量的情况，如卡西米尔效应和光的压缩状态，已经在实验室中产生。然而，在这些实验中产生的负能量非常微小，因此无法直接测量。然而，如果物理定律对负能量没有限制，那么人们可能会创造出大量的负能量，从而产生奇异的宏观效应。这些效应可能包括：可穿越虫洞（连接遥远空间和时间区域的隧道）、曲速驱动（超光速旅行）、穿越过去的时间机器、违反热力学第二定律（例如，冰箱不需要电源）以及黑洞的破坏（坍缩的死恒星的残骸）。然而，L. Ford （Tufts U.）和PI十多年来的研究表明，量子场论确实对负能量施加了一些相当强的限制。这些约束被称为“量子不平等”，并且对上述可能的宏观效应产生了严重的限制，因为它们意味着大的负能量只能在很短的时间内存在。迄今为止获得的理论结果表明，负能量必然与空间中的正能量微妙地交织在一起。一个悬而未决的问题是，这在多大程度上是正确的。部分研究将集中在缩小负能量分布之间的差距，负能量分布是可以排除的，而负能量分布是绝对允许的。主要的重点将放在涉及负能量的量子态的研究上，这些量子态可以使用量子光学技术产生。研究的一个相关但较小的部分将致力于研究负能量、能量守恒、黑洞蒸发和可能的毁灭之间的联系。这项工作位于物理学的三个重要领域的交叉点，并对它们产生了深远的影响：量子场论、爱因斯坦的引力理论（广义相对论）和热力学。这项研究的一个主要目标是在负能量研究和快速发展的量子光学领域之间建立更紧密的联系。在这两个物理学领域之间建立这样的联系，至少可以对负能量的间接影响进行实验测试。在过去的十年里，一个小型但非常活跃的国际研究小组在负能量这一主题上成长起来。计划让本科生参与这个项目。

This award supports a research project to study the implications of a very unusual form of energy. The existence of this so-called ``negative energy'' is allowed by the laws of quantum field theory, which describe the behavior of matter and energy on microscopic scales. Negative energy would also have repulsive gravitational effects. Situations involving negative energy, such as the Casimir effect and squeezed states of light, have been produced in the laboratory. However, the amounts of negative energy generated in these experiments are extremely tiny and hence not directly measurable. However, if the laws of physics impose no constraints on negative energy, then one might be able to create large amounts of it and thereby produce bizarre macroscopic effects. Such effects could include: traversable wormholes (tunnels connecting otherwise distant regions of space and time), warp drives (for faster-than-light travel), time machines for travel into the past, violations of the second law of thermodynamics (e.g., refrigerators requiring no power sources), and the destruction of black holes (the remains of collapsed dead stars). However, research by L. Ford (Tufts U.) and the PI over more than a decade has shown that quantum field theory does impose some rather strong restrictions on negative energy. These constraints have come to be known as ``quantum inequalities,'' and yield severe limitations on the possible macroscopic effects mentioned above because they imply that large negative energies can exist for only short periods of time. The theoretical results obtained to date indicate that negative energy must be subtly intertwined with positive energy in space. An unanswered question is to what extent this must be true in general. Part of the research will be focused on narrowing the gap between distributions of negative energy which can be ruled out and those which are definitely allowed. The primary emphasis will be on a study of quantum states which involve negative energy and which can be produced using the techniques of quantum optics. A related, but smaller, part of the research will aim to study the connections between negative energy, energy conservation, and the evaporation and possible destruction of black holes.This work lies at the intersection of, and deeply impacts, three important areas of physics: quantum field theory, Einstein's theory of gravity (general relativity), and thermodynamics. A primary goal of this research is to establish closer ties between this work on negative energy and the rapidly growing field of quantum optics. Such a link between these two areas of physics might allow experimental tests of at least the indirect effects of negative energy. The last ten years have seen the growth of a small but very active international group of researchers on the subject of negative energy. It is planned to involve undergraduates in this project.