标题： 从天体状态中得到的新配对增强量子数 显示英文标题

标题： A new pairwise boost quantum number from celestial states

摘要： 在引力和电磁动力学中粒子散射的红外效应涉及粒子对与规范场之间相对论角动量的交换。 由于这种交换，粒子可以携带渐近非消失的"成对"类提升角动量，该角动量与它们对场的耦合乘积成比例。 在量子层面，这种渐近角动量暗示了多粒子态携带的新量子数的存在。 我们认为这种量子数与洛伦兹变换生成元在多粒子态上的作用的修改有关。 我们通过基于渐近态的共形原基的小群的群论论证推导出这种修改。 相应的表示是庞加莱群的普通多粒子福克表示的扩展。 属于这种表示的新多粒子态不再能分解为单粒子态的张量积。 从引力的观点来看，我们的结果提供了由于红外反作用导致在福克空间中描述多粒子态的普遍失效的证据。 显示英文摘要

摘要： Infrared effects in the scattering of particles in gravity and electrodynamics entail an exchange of relativistic angular momentum between pairs of particles and the gauge field. Due to this exchange particles can carry an asymptotically non-vanishing "pairwise" boost-like angular momentum proportional to the product of their couplings to the field. At the quantum level this asymptotic angular momentum suggests the existence of a new quantum number carried by multi-particle states. We argue that such quantum number is related to a modification of the action of the generators of Lorentz transformations on multi-particle states. We derive such a modification using a group-theoretic argument based on the little group of the conformal primary basis for asymptotic states. The corresponding representation is an extension of the ordinary multi-particle Fock representation of the Poincar\'e group. The new multi-particle states belonging to such representation no longer factorize into tensor products of one-particle states. Viewed from a gravitational point of view, our results provide evidence for a universal breakdown of the description of multi-particle sates in terms of Fock space due to infrared back-reaction.