Gravitational positivity bounds

Understand

We study the validity of positivity bounds in the presence of a massless graviton, assuming the Regge behavior of the amplitude.

• Under this assumption, the problematic $t$-channel pole is canceled with the UV integral of the imaginary part of the amplitude in the dispersion relation, which gives rise to finite corrections to the positivity bounds.
• We find that low-energy effective field theories (EFT) with "wrong" sign are generically allowed.
• The allowed amount of the positivity violation is determined by the Regge behavior.