| Extremal couplings, graviton exchange, and gluon scattering in AdS |
| Shai Chester, Imperial College |
| Event Type: Special Seminar |
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| Time: 12:30 PM - 1:30 PM |
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| Location: 726 Broadway, 940, CCPP Seminar |
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| Abstract: Extremal cubic couplings in AdS relate bulk fields such that $Delta_i+Delta_j=Delta_k$. Such couplings lead to divergent 3-point Witten diagrams, and do not occur in theories with maximal supersymmetry. We consider the simplest theories where such coupling are non-zero, which are string or M-theory on singular spacetimes with fixed point loci AdS_{d+1}xS^3 for d=3,4,6, which are dual to CFTs in d dimensions. These theories have infinite towers of graviton modes, as well as gluon modes on the singularities. We compute the nonzero coupling between these modes, which is in general (super)-extremal. We use these couplings to compute the graviton exchange term in the holographic correlator of gluon KK modes, which we match to the expected answer in the flat space limit. We then use this graviton exchange term to compute the unmixing of the single trace graviton modes with double traces of gluon modes, which explains the divergent 3-point diagrams. Link to the Event Video |