Theoretical limits on agegraphic quintessence from weak gravity conjecture

In this Letter, we investigate the possible theoretical constraint on the parameter n of the agegraphic quintessence model by considering the requirement of the weak gravity conjecture that the variation of the quintessence scalar field φ should be less than the Planck mass Mp. We obtain the theoretical upper bound n≤2.5 that is inconsistent with the current observational constraint result 2.637<n<2.983 (95.4% CL). The possible implications of the tension between observational and theoretical constraint results are discussed.