Constraints on Gravitation from Causality and Quantum Consistency
Constraints on Gravitation from Causality and Quantum Consistency
复制标题
因果关系和量子一致性对引力的约束
DOI：
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发表时间：
2016
影响因子：
1.7
通讯作者：
M. Hertzberg
中科院分区：
文献类型：
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作者：
M. Hertzberg
我们研究的作用，因果关系和量子力学的一致性，在确定引力的性质。我们开始通过检查两种不同的无质量自旋2粒子-引力子相互作用理论。一种是将导数最小的引力子耦合到物质上，另一种是利用线性化的黎曼张量将导数更高的引力子耦合到物质上。第一类需要一个无限大的项来保证一致性，这是唯一导致广义相对论的原因。第二类只需要有限数目的项来保持一致性，它作为另一类无质量自旋2的理论出现。我们回顾了广义相对论的因果一致性，并展示了如何在第二类耦合到光子的特殊情况下失败，利用文献中的相关计算。在Hertzberg and Sandora（2017）的一篇配套论文中，这个结果被推广到更广泛的理论。然后，作为广义相对论的因果修正，我们加入了轻标量粒子，并概括了它们引入的普遍自由落体的一般违反及其量子分辨率。这就引出了对一种特殊类型的标量-张量理论的讨论：F（R）模型。我们表明，与广义相对论不同，这些模型不具备必要的反项是一致的量子有效场论。这有助于消除在推导广义相对论时所做的一些核心假设。
We examine the role of consistency with causality and quantum mechanics in determining the properties of gravitation. We begin by examining two different classes of interacting theories of massless spin 2 particles—gravitons. One involves coupling the graviton with the lowest number of derivatives to matter, the other involves coupling the graviton with higher derivatives to matter, making use of the linearized Riemann tensor. The first class requires an infinite tower of terms for consistency, which is known to lead uniquely to general relativity. The second class only requires a finite number of terms for consistency, which appears as another class of theories of massless spin 2. We recap the causal consistency of general relativity and show how this fails in the second class for the special case of coupling to photons, exploiting related calculations in the literature. In a companion paper Hertzberg and Sandora (2017), this result is generalized to a much broader set of theories. Then, as a causal modification of general relativity, we add light scalar particles and recap the generic violation of universal free-fall they introduce and its quantum resolution. This leads to a discussion of a special type of scalar-tensor theory: the F(R) models. We show that, unlike general relativity, these models do not possess the requisite counterterms to be consistent quantum effective field theories. Together this helps to remove some of the central assumptions made in deriving general relativity.