论文标题
爱因斯坦重力是否涉及黎曼张量的协变量？
Are there Einsteinian gravities involving covariant derivatives of the Riemann tensor?
论文作者
论文摘要
我们研究了用黎曼张量及其协变量衍生物收缩建立的高导数理论的粒子含量。在没有后者的情况下，有一系列理论表现出爱因斯坦谱，称为广义准则重力。反过来，我们对涉及riemann张量的协变量的爱因斯坦重力的构建产生了无关的结果。我们发现证据表明（截断的系列）有限秩序的拉格朗日人具有riemann张量的协变量，通常在其频谱中呈现鬼魂。这可能被解释为在任何健康的紫外线完成一般相对论中的非本地性暗示。
We study the particle content of higher derivative theories of gravity built with contractions of the Riemann tensor and its covariant derivatives. In the absence of the latter, there is a family of theories exhibiting an Einsteinian spectrum known as generalized quasi-topological gravities. In turn, we present a no-go result for the construction of Einsteinian gravities involving covariant derivatives of the Riemann tensor. We find evidences suggesting that (truncated series) finite order Lagrangians with covariant derivatives of the Riemann tensor generically present ghosts in their spectrum. This might be interpreted as a hint of non-locality in any healthy UV completion of General Relativity.
