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arXiv · 1912.10973

Extended BMS Algebra of Celestial CFT

Angelos Fotopoulos·Stephan Stieberger·Tomasz R. Taylor·Bin Zhu
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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 spacetime. 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 $\mathfrak{bms_4}$. 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.

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Angelos Fotopoulos, Stephan Stieberger, Tomasz R. Taylor, Bin Zhu. 2019-12-23. Extended BMS Algebra of Celestial CFT. https://doi.org/10.1007/jhep03(2020)130

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