Goldilocks modes in celestial CFT

13.04.2022 14:00 – 15:00

In this talk I will consider massless scattering from the point of view of the position, momentum, and celestial bases with a view to advancing a holographic principle for asymptotically flat spacetimes. Within the soft sector, these different languages highlight distinct aspects of the 'infrared triangle': quantum field theory soft theorems arise in the limit of vanishing energy, memory effects are described via shifts of fields along retarded time, and celestial symmetry algebras are realized via currents that appear at special values of the conformal dimension. The latter are determined by the global conformal multiplets in celestial CFT referred to as 'celestial diamonds'. These diamonds degenerate beyond the leading universal soft modes and the standard interpretation of the infrared triangle breaks down: we have neither an obvious asymptotic symmetry nor a Goldstone mode but we do have a soft theorem, and hence a version of a memory effect. I will discuss various aspects of celestial CFT surrounding these Goldstone-like, or Goldilocks, modes and their canonically paired memory modes. They play an important role in constraining celestial OPEs and for understanding the interpretation and implications of the (semi-)infinite tower of tree-level symmetry currents which may pose powerful constraints on consistent low energy effective field theories.

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Bâtiment: Sciences I

306

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