Title: [NCTS-NTU String Theory Seminar] Scaling exponents of Mellin amplitudes for deriving bounds on flat space S-matrices from bounds on chaos
Speaker: Dr. Mitsuhiro Nishida (GIST, Gwangju)
Time: Apr. 22, 2022 (Fri) 14:30-15:30
Venue: Online
Webex Link:
https://nationaltaiwanuniversity-zbh.my.webex.com/nationaltaiwanuniversity-zbh.my/j.php?MTID=mdf2849ce7ba719d80f4eec0705b01ebf

Abstract:
We study an inequality between a scaling exponent $A$ in the Regge limit of tree-level flat space S-matrices with external massless scalars and another scaling exponent $A'$ in the Regge limit of the corresponding four-point scalar conformal correlators by using scaling exponents of Mellin amplitudes. We derive $A'\ge A$, which leads to the Regge growth bound of tree-level flat space S-matrices from the chaos bound in the flat space limit of the AdS/CFT correspondence, from polynomial boundedness of the Mellin amplitudes for local bulk descriptions. We also show $A'=A$ from the conformal block expansion in the $t$-channel with finite intermediate spins when coefficients are not small in the flat space limit.