The SAGEX Review on Scattering Amplitudes, Chapter 8: Half BPS correlators

Understand

Half BPS correlators in N=4 super Yang-Mills theory are key quantities both in the AdS/CFT correspondence as well as in scattering amplitudes research.

• They are dual at strong coupling to quantum gravity amplitudes.
• At weak coupling on the other hand they contain all N=4 SYM amplitudes.
• They have been found to possess a number of hidden symmetries, for example non-trivial permutation symmetry of perturbative four-point integrands and a higher dimensional conformal symmetry.