Classical Soft Graviton Theorem Rewritten

Abstract

Classical soft graviton theorem gives the gravitational wave-form at future null infinity at late retarded time $u$ for a general classical scattering. The large $u$ expansion has three known universal terms: the constant term, the term proportional to $1/u$ and the term proportional to $\ln u/u^2$, whose coefficients are determined solely in terms of the momenta of incoming and the outgoing hard particles, including the momenta carried by outgoing gravitational and electromagnetic radiation produced during scattering. For the constant term, also known as the memory effect, the dependence on the momenta carried away by the final state radiation / massless particles is known as non-linear memory or null memory. It was shown earlier that for the coefficient of the $1/u$ term the dependence on the momenta of the final state massless particles / radiation cancels and the result can be written solely in terms of the momenta of the incoming particles / radiation and the final state massive particles. In this note we show that the same result holds for the coefficient of the $\ln u/u^2$ term. Our result implies that for scattering of massless particles the coefficients of the $1/u$ and $\ln u/u^2$ terms are determined solely by the incoming momenta, even if the particles coalesce to form a black hole and massless radiation. We use our result to compute the low frequency flux of gravitational radiation from the collision of massless particles at large impact parameter.

LaTeX file, 21 pages; v2: added a section containing computation of flux of soft radiation during scattering of massless particles

References in corpus (6)

• The gravitational-wave memory effect
• Infrared features of gravitational scattering and radiation in the eikonal approach
• Classical Sub-subleading Soft Photon and Soft Graviton Theorems in Four Spacetime Dimensions
• Soft gravitational radiation from ultra-relativistic collisions at sub- and sub-sub-leading order
• New Asymptotic Conservation laws for Electromagnetism
• Asymptotic conservation law with Feynman boundary condition

Cited by in corpus (6)

• The SAGEX Review on Scattering Amplitudes, Chapter 11: Soft Theorems and Celestial Amplitudes
• Angular momentum of zero-frequency gravitons
• Goldilocks Modes and the Three Scattering Bases
• Spin Dependent Gravitational Tail Memory in $D=4$
• Electromagnetic multipole expansions and the logarithmic soft photon theorem
• Soft gravitational radiation from multi-body collisions