Extended BMS algebra of celestial CFT

• DOI: 10.1007/jhep03(2020)130
• Publication Date: 2020-03-24T01:04:11Z
• Authors: Angelos Fotopoulos; Stephan Stieberger; Tomasz R. Taylor; Bin Zhu
• Keywords: High Energy Physics - Theory; Conformal Field Theory; High Energy Physics - Theory (hep-th); Nuclear and particle physics. Atomic energy. Radioactivity; 0103 physical sciences; FOS: Physical sciences; QC770-798; General Relativity and Quantum Cosmology (gr-qc); Scattering Amplitudes; 01 natural sciences; General Relativity and Quantum Cosmology

Abstract We elaborate on the proposal of flat holography in which four-dimensional physics is encoded in two-dimensional celestial conformal field theory (CCFT). The symmetry underlying CCFT is the extended BMS symmetry of (asymptotically) flat space­ time. We use soft and collinear theorems of Einstein-Yang-Mills theory to derive the OPEs of BMS field operators generating superrotations and supertranslations. The energy­ momentum tensor, given by a shadow transform of a soft graviton operator, implements superrotations in the Virasoro subalgebra of 𝔟𝔪𝔰4. Supertranslations can be obtained from a single translation generator along the light-cone direction by commuting it with the energy-momentum tensor. This operator also originates from a soft graviton and generates a flow of conformal dimensions. All supertranslations can be assembled into a single primary conformal field operator on celestial sphere.