Gauge-Invariant Double-Copies via Recursion

TL;DR

This paper demonstrates that all tree-level gravity amplitudes can be represented as gauge-invariant double-copies of Yang-Mills amplitudes obtained through BCFW recursion, highlighting the variety of such representations.

Contribution

It establishes a proof that all tree-level (super-)gravity amplitudes can be expressed as gauge-invariant double-copies of (super-)Yang-Mills amplitudes via BCFW recursion, showing the non-uniqueness of these representations.

Findings

All tree-level gravity amplitudes can be expressed as gauge-invariant double-copies.

Different recursive schemes produce a variety of valid double-copy representations.

The double-copy representations are not unique, allowing for multiple valid formulations.

Abstract

We prove that all tree-level amplitudes in pure (super-)gravity can be expressed as term-wise, gauge-invariant double-copies of those of pure (super-)Yang-Mills obtained via BCFW recursion. These representations are far from unique: varying the recursive scheme leads to a wide variety of distinct, but equally valid representations of gravitational amplitudes, all realized as double-copies.