Celestial amplitudes and conformal soft theorems

By Tim Adamo, L. Mason, A. Sharma. Classical and quantum gravity, 2019

146 citations recorded by the source corpus.

Scattering amplitudes in d  +  2 dimensions can be expressed in terms of a conformal basis, for which the S-matrix behaves as a CFT correlation function on the celestial d-sphere. We explain how compact expressions for the full tree-level S-matrix of gauge theory, gravity and other QFTs extend to this conformal basis, and are easily derived from ambitwistor strings. Using these formulae and their worldsheet origins, we prove various tree-level ‘conformal soft theorems’ in gauge theory and gravity in any dimension; these arise from limits where the scaling dimension of an external state in the scattering process takes special values. These conformally soft limits are obscure from standard methods, but they are easily derived with ambitwistor strings. Additionally, we make an identification between the residues of conformally soft vertex operator insertions in ambitwistor strings and charges generating asymptotic symmetries.

Subfields: Geometry and Topology, Mathematical Physics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/38af47f5402bc37d8fcc586a2ae1b89218611319

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In Geometry and Topology

1. Sabrina Pasterski
2. Andrew Strominger
3. M. Pate
4. Ashoke Sen

In Mathematical Physics

1. Andrew Strominger
2. M. Pate
3. A. Guevara
4. Ashoke Sen

In Nuclear and High Energy Physics

1. Sabrina Pasterski
2. M. Pate
3. Andrew Strominger
4. A. Raclariu
5. A. Guevara
6. E. Himwich
7. L. Donnay
8. M. Perry

Citations in the corpus

• Celestial operator products of gluons and gravitons (2019, unknown): “Celestial operator spectra were studied in [4–11] and celestial scattering amplitudes in [12–25].”
• Holographic symmetry algebras for gauge theory and gravity (2021, methodology): “In 4D nonabelian gauge theory with group G, the leading soft theorem implies a standard closed 2D celestial G-current algebra [24, 38, 43, 46, 67].”
• Celestial Holography (2021, background): “In the first category, we have a wide variety of efforts to understand loop effects [125, 137–139], double copy relations [140–143], supersymmetry [21, 22, 115, 131, 143–149], changes in signature [102, 150, 151], twistor methods [104, 111, 152, 153], and more general amplitudes techniques [146, 147”