Soft Gravity by Squaring Soft QED on the Celestial Sphere

Double Copy for Celestial Amplitudes

Celestial amplitudes which use conformal primary wavefunctions rather than plane waves as external states offer a novel opportunity to study properties of amplitudes with manifest conformal covariance and give insight into a potential holographic celestial CFT at the null boundary of asymptotically flat space. Since translation invariance is obscured in the conformal basis, features of amplitudes that heavily rely on it appear to be lost. Among these are the remarkable relations between gauge theory and gravity amplitudes known as the double copy. Nevertheless, properties of amplitudes reflect…

Zwanziger's pairwise little group on the celestial sphere

We generalize Zwanziger's pairwise little group to include a boost subgroup. We do so by working in the celestial sphere representation of scattering amplitudes. We propose that due to late time soft photon and graviton exchanges, matter particles in the asymptotic states in massless QED and gravity transform under the Poincare group with an additional pair of pairwise celestial representations for each pair of matter particles. We demonstrate that the massless abelian and gravitational exponentiation theorems are consistent with the proposed pairwise Poincare transformation properties. For ma…

The Holographic Soft $S$-Matrix in QED and Gravity

At leading order, the $S$-matrices in QED and gravity are known to factorise, providing unambiguous determinations of the parts divergent due to infrared contributions. The soft $S$-matrices defined in this fashion are shown to be defined entirely in terms of $2$ dimensional models on the celestial sphere, involving two real scalar fields, allowing us to express the soft $S$-matrices for real as well as virtual divergences as two dimensional correlation functions. We discuss what this means for finding holographic representations of scattering amplitudes in QED and gravity and comment on simpl…

QED中来自Banerjee–Mandal–Sahoo偶极子Ward恒等式的有限能硬天球流代数

Finite-energy hard celestial current algebra from the Banerjee--Mandal--Sahoo dipole Ward identity in QED

利用Banerjee–Mandal–Sahoo偶极子流Ward恒等式，推导出其对Mellin差硬流的有限能作用，得到与方案无关的硬-硬留数，并证明其定义了一个最小过滤阿贝尔扩张，与Choi-Kadhe-Puhm的长程对数塔一致。

存储在天球上的光子手征记忆效应

Photon Chiral Memory Effect Stored on Celestial Sphere

提出天球上的光子手征记忆效应，以电磁场自旋角动量的永久变化刻画手征相互作用，并用零无穷远拓扑轴矢流在横向规范中表述。

天体共形场论中的长程相互作用

Long-Range Interactions in Celestial CFT

研究揭示了天体共形场论中长程相互作用的根源，通过定义共形软环算符并计算其算符乘积展开，展示了环形修正如何由硬算符之间的 gauge 质子交换驱动。