Quantum Gravity Constraints from Unitarity and Analyticity
Quantum Gravity Constraints from Unitarity and Analyticity
复制标题
来自幺正性和解析性的量子引力约束
DOI：
--
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Grant N. Remmen
中科院分区：
文献类型：
--
作者：
B. Bellazzini;C. Cheung;Grant N. Remmen
利用引力子散射振幅的么正性和解析性，推导出爱因斯坦引力修正的严格界。在D≥4维的时空中，这些相容性条件要求某些四次曲率算子具有正系数。我们系统地列举了D=4和D=5中的所有正性界，然后扩展到D≥6。之后，我们推导出超对称算子的正性界，并验证了弱耦合弦理论满足我们所有的约束条件。在二次曲率算子中，我们发现D≥5的Gauss-Bonnet项是不一致的，除非新的自由度进入有效理论定义的自然截止尺度。我们的界限适用于引力的微扰紫外完备化。
We derive rigorous bounds on corrections to Einstein gravity using unitarity and analyticity of graviton scattering amplitudes. In D≥4 spacetime dimensions, these consistency conditions mandate positive coefficients for certain quartic curvature operators. We systematically enumerate all such positivity bounds in D=4 and D=5 before extending to D≥6. Afterwards, we derive positivity bounds for supersymmetric operators and verify that all of our constraints are satisfied by weakly coupled string theories. Among quadratic curvature operators, we find that the Gauss-Bonnet term in D≥5 is inconsistent unless new degrees of freedom enter at the natural cutoff scale defined by the effective theory. Our bounds apply to perturbative ultraviolet completions of gravity.