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Conventions

In CFT-related pages, the following terminologies are adopted without further specification:

Term Meaning
Virasoro CFT CFT with Virasoro symmetry on \(\RR^{2}\)
(Euclidean) CFT CFT with \(\solie(d+1,1)\) symmetry on \(\RR^{d}\)
Lorentzian CFT CFT with \(\solie(d,2)\) symmetry on \(\RR^{d-1,1}\)
Virasoro primary/descendant vectors in Verma modules of Virasoro algebra
primary/descendant vectors in parabolic Verma modules of \(\solie(d+2,\CC)\)
(Euclidean) principal series Harish-Chandra modules of \(\solie(d+1,1)\)
Lorentzian principal series Harish-Chandra modules of \(\solie(d,2)\)
BPZ/Lorentzian conjugation $Q_{L}^{\dagger}=-Q_{L}\, \implies\, D^{\dagger}=D, P^{\dagger}=K, \dots $
dS/Euclidean conjugation $Q_{E}^{\dagger}=-Q_{E}\, \implies\, D^{\dagger}=-D, P^{\dagger}=-P, \dots $

The metric signature is most positive. The conserved charges are anti-Hermitian by default. The local operators on \(\RR^{d}\) and \(\RR^{d-1,1}\) are distinguished by \(\op_{E}(x)\) and \(\op_{L}(x)\) if necessary, and \(\op_{i}\) denotes \(\op_{i}(0)\) or \(\op_{i}(x_{i})\) according to the context.

Celestial CFT Usual CFT
\(\solie(d+1,1)\)/Virasoro \(\solie(d+1,1)\)/Virasoro
gauge symmetry current algebra
supertranslation Carrollian and its extension
BGG modules BGG modules
HC modules /
colinear singularity OPE singularity
other singularities ?
single-valuedness locality (?)
celestial optical theorem /
spacetime crossing ?