In this review we describe a non-trivial relationship between perturbative gauge theory and gravity scattering amplitudes. At the semi-classical or tree-level, the scattering amplitudes of gravity theories in flat space can be expressed as a sum of products of well defined pieces of gauge theory amplitudes. These relationships were first discovered by Kawai, Lewellen, and Tye in the context of string theory, but hold more generally. In particular, they hold for standard Einstein gravity. A method based on D-dimensional unitarity can then be used to systematically construct all quantum loop corrections order-by-order in perturbation theory using as input the gravity tree amplitudes expressed in terms of gauge theory ones. More generally, the unitarity method provides a means for perturbatively quantizing massless gravity theories without the usual formal apparatus associated with the quantization of constrained systems. As one application, this method was used to demonstrate that maximally supersymmetric gravity is less divergent in the ultraviolet than previously thought.
展开▼
机译：在这篇综述中，我们描述了扰动量规理论与重力散射幅度之间的非平凡关系。在半古典或树级别，重力理论在平面空间中的散射幅度可以表示为规范理论幅度的明确定义的乘积之和。这些关系最初是由Kawai，Lewellen和Tye在弦论的背景下发现的，但更普遍。特别是，它们适用于标准爱因斯坦引力。然后，可以使用基于 D 维统一性的方法，以扰动理论为基础，以重力树振幅为输入，系统地构造所有量子环路校正。规范理论的。更一般地，单一性方法提供了一种扰动量化无质量重力理论的方法，而无需与约束系统的量化相关联的通常形式化的装置。作为一种应用，此方法用于证明最大超对称重力在紫外线中的散度比以前认为的要小。
展开▼
