Theoretical Limits on Agegraphic Quintessence from Weak Gravity Conjecture

In this paper, 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 $\varphi$ should be less than the Planck mass $M_{\mathrm{p}}$. We obtain the theoretical upper bound $n\lesssim 2.5$ 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.