标题： 在弯曲时空中的粒子包装 显示英文标题

标题： Packaging particles in curved spacetimes

摘要： 在弯曲时空中的散射计算在技术上非常复杂，在一般时空度规的情况下几乎不可能完成。 即使在可以进行微扰散射计算的情况下，也必须注意什么样的粒子是可测量的。 因此，弯曲时空量子场论在概念上不如平直时空中的清晰。 在本文中，我们研究这种概念混乱的一个方面——在定义S矩阵时使用波包。 波包在大多数标准教科书处理中被用来构造粒子态并消除S矩阵定义中的某些奇点。 我们首先以一种普遍的方式，然后通过一个具体模型来证明这种方法在弯曲时空中并不完全有效。 我们还讨论了相关效应，并提出了一种进行弯曲时空散射计算的方法。 我们的结论是，弯曲时空中最通用的散射计算方法需要使用波包，而这些波包通常在文献中是缺失的。 显示英文摘要

摘要： Scattering calculations in curved spacetime are technically complicated and, in the case of a general spacetime metric, quite impossible. Even in the cases where perturbative scattering calculations can be done one has to be careful about what kind of particles are sensible to measure. Curved spacetime quantum field theories are then less conceptually clear than those in flat spacetime. In this article, we investigate an aspect of this conceptual confusion - the use of wave packets in defining the S-matrix. Wave packets are used in most standard textbook treatments to construct particle states and remove certain singularities in the definition of the S-matrix. We show that this method does not completely work in curved spacetimes first in a general way and then by way of a specific model. We also discuss related effects and suggest a method for doing curved spacetime scattering calculations. Our conclusion is that the most general method for scattering calculations in curved spacetimes requires the use of wave packets, which are typically absent in the literature.