SciPost Submission Page
Split representation in celestial holography
by Chi-Ming Chang, Reiko Liu, Wen-Jie Ma
Submission summary
| Authors (as registered SciPost users): | Chi-Ming Chang · Wenjie Ma |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202312_00032v1 (pdf) |
| Date submitted: | 2023-12-17 09:41 |
| Submitted by: | Ma, Wenjie |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
We develop a split representation for celestial amplitudes in celestial holography, by cutting internal lines of Feynman diagrams in Minkowski space. More explicitly, the bulk-to-bulk propagators associated with the internal lines are expressed as a product of two boundary-to-bulk propagators with a coinciding boundary point integrated over the celestial sphere. Applying this split representation, we compute the conformal partial wave and conformal block expansions of celestial four-point functions of massless scalars and photons on the Euclidean celestial sphere. In the $t$-channel massless scalar amplitude, we observe novel intermediate exchanges of staggered modules in the conformal block expansion.
Current status:
Reports on this Submission
Strengths
interesting result, clean presentation, detailed appendices
Weaknesses
n/a
Report
The authors are developing a more systematic way to compute conformal partial waves for celestial amplitudes. I think this is an interesting result and I'm happy to endorse its publication. I also appreciate the efficiency in presenting the result of the paper paired with the extended pedagogy in the appendices.
Requested changes
The statements about helicity vs spin at the beginning of section 5.2 are a little confusing. I'd recommend using helicity for the 4D quantities and spin for the 2D ones if everything is massless. I don't like the sentence that the shadow flips the helicity -- I think you just mean 2D spin, hence my comment above.