Speaker: Wenjie Ma (SIMIS, Fundan U.)
Time: 2025-12-10 16:00-18:00
Location: 1710, SIMIS
Zoom Meeting ID: 898 6775 9309 Passcode: 645143
Abstract:
I will present two components of my work pertaining to celestial holography.
In the first part, I will describe a method for reconstructing four-point, massless scattering amplitudes within the celestial holography framework. This method depends solely on conformal field theory (CFT) techniques and a remarkable property: the scattering amplitudes can be derived from a single conformal block coefficient in the celestial CFT. Employing this method, we successfully reconstruct the Maximally Helicity Violating (MHV) amplitudes in pure Yang-Mills theory, pure gravity, and Einstein-Yang-Mills theories.
In the second part, I will introduce the concept of regular celestial amplitudes. A foundational challenge in celestial holography is an apparent inconsistency between the celestial operator product expansion (OPE) and the structure of celestial amplitudes. Specifically, in Yang-Mills theory, the well-established OPE for positive-helicity gluons not only fails to appear in three- and four-point MHV amplitudes but also predicts a non-zero result for the non-MHV amplitude ⟨+++−⟩, which directly contradicts its vanishing value in momentum space. To resolve this contradiction, we introduce regular celestial amplitudes as a completion of the standard framework. We demonstrate that at tree level, these amplitudes are non-distributional and, most importantly, form a closed algebra under the known celestial OPEs, thereby restoring consistency to the holographic dictionary.
About Speaker:
Wenjie Ma is an Assistant Professor at SIMIS and Fudan University. Prior to joining SIMIS, he served as a Postdoctoral Research Scholar at Yau Mathematical Sciences Center of Tsinghua University and Yanqi Lake Beijing Institute of Mathematical Sciences and Applications (BIMSA). He obtained his Ph.D in physics at Laval University in 2021. His current research interests mainly focus on conformal field theory and the principle of holography, including non-perturbative booststrap program, AdS/CFT, dS/CFT as well as celestial holography.
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