A Twistorial Foundation for the Classical Double Copy

彭罗斯变换与克尔-施金德双倍复制

The Penrose Transform and the Kerr-Schild double copy

研究指出，对于一类自双曲真空解，彭罗斯变换与克尔-施金德双倍复制方法等价，通过null洛伦兹变换和twistor空间的同次函数证明，并以自双曲(Kerr)-塔布-努特时空为例说明。

Massive ambitwistor-strings; twistorial models

Ambitwistor-strings are chiral strings whose targets are spaces of complex massless particles, and whose correlation functions directly lead to simple, compact formulae for scattering amplitudes and loop integrands for massless gauge and gravity theories. This article extends this framework to worldsheet models for massive particles in 4d, obtained via a symmetry reduction of a higher dimensional massless model. The target space of the resulting models turns out to be the phase space of 4d massive particles in a twistorial representation, and so the worldsheet theory agrees with the two-twisto…

Why is the Weyl double copy local in position space?

The double copy relates momentum-space scattering amplitudes in gauge and gravity theories. It has also been extended to classical solutions, where in some cases an exact double copy can be formulated directly in terms of products of fields in position space. This is seemingly at odds with the momentum-space origins of the double copy, and the question of why exact double copies are possible in position space and when this form will break has remained largely unanswered. In this paper, we provide an answer to this question, using a recently developed twistorial formulation of the double copy. …

Twistor Space Origins of the Newman-Penrose Map

Recently, we introduced the "Newman-Penrose map," a novel correspondence between a certain class of solutions of Einstein's equations and self-dual solutions of the vacuum Maxwell equations, which we showed was closely related to the classical double copy. Here, we give an alternative definition of this correspondence in terms of quantities that are defined naturally on twistor space, and a shear-free null geodesic congruence on Minkowski space whose twistorial character is articulated by the Kerr theorem. The advantage of this reformulation is that it is purely geometrical in nature, being ma…

Classical double copy at null infinity

We give two double copy prescriptions which construct asymptotically flat solutions in gravity from asymptotically flat gauge fields. The first prescription applies to radiative fields, which are non-linear vacuum solutions determined by characteristic data at null infinity. For any two such radiative gauge fields (linear or non-linear), the characteristic data of a radiative metric, dilaton and axion is constructed by a simple `squaring' procedure, giving a classical double copy at the level of radiation fields. We demonstrate the procedure with several examples where the characteristic data …

树级形状因子的双重拷贝。第一部分：基础

Double copy for tree-level form factors. Part I. Foundations

本文建立了树级形状因子的双重拷贝构造的一般形式，详细讨论了伪极点转化为引力物理极点的机制，并推广至QCD中的Higgs振幅与多外部标量态情形。