标题： 无鬼粒子无限导数量子引力中接触项的平滑处理 显示英文标题

标题： Smearing out contact terms in ghost-free infinite derivative quantum gravity

摘要： 在无鬼场无限导数引力的背景下，我们考虑两个无自旋粒子之间、一个无自旋粒子和一个光子之间，或一个无自旋粒子和一个自旋1/2粒子之间的单引力子交换。 为此，我们计算上述三种情况的引力势，并推导出在线性化水平下出现的$\mathcal{O}(G\hbar^2)$修正项。 在局部理论中，众所周知，这种修正以狄拉克δ函数的形式出现。 在这里，我们表明对于非局部理论，这种修正被模糊化了，并且与局部理论相反，在两个粒子之间存在非零分离时，它具有非零值。 在无自旋粒子和自旋1/2粒子之间的单引力子交换情况下，我们还计算了在非相对论近似下非静态情况下出现的$\mathcal{O}(G\hbar)$修正项，并表明在非局部理论中它是有限的。 显示英文摘要

摘要： In the context of ghost-free infinite derivative gravity, we consider the single graviton exchange between two spinless particles, a spinless particle and a photon, or between a spinless particle and a spin-1/2 particle. To this end, we compute the gravitational potential for the three aforementioned cases and derive the $\mathcal{O}(G\hbar^2)$ correction that arises at the linearised level. In the local theory, it is well-known that such a correction appears in the form of a Dirac delta function. Here, we show that this correction is smeared out for the nonlocal theory and, in contrast to the local theory, takes on non-zero values for a non-zero separation between the two particles. In the case of the single graviton exchange between a spinless particle and a spin-1/2 particle, we also compute the $\mathcal{O}(G\hbar)$ correction that arises in the non-static case within the non-relativistic approximation and show that it is finite in the nonlocal theory.