Cohen-Kaplan-Nelson Bound and Minimum Coupling in Effective Field Theories.

We argue that the Cohen-Kaplan-Nelson (CKN) bound -- relating the ultraviolet and infrared cutoff scales of an effective field theory -- implies a Minimum Coupling Condition (MCC) that is much stronger than that obtained from the Weak Gravity Conjecture. This can be traced to the more stringent nature of the CKN bound compared to that obtained from Bekenstein's maximal entropy requirement. The MCC would not allow for Dirac neutrinos in the Standard Model and suggests its UV cutoff scale is below $\sim 10^4$ TeV, from the inferred size of the electron Yukawa coupling. We also slightly extend the CKN bound, by accounting for the effective degrees of freedom, and examine some of its phenomenological implications.