In a theory with linear confinement, such as QCD, the masses squared m 2 n,S of mesons with high spin S or high radial excitation number n are expected, from semiclassical arguments, to grow linearly with S and n. We show that this behavior can be reproduced within a putative 5-dimensional theory holographically dual to QCD (AdS/QCD). With the assumption that such a dual theory exists and describes highly excited mesons as well, we show that asymptotically linear m 2 spectrum translates into a

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... trong constraint on the infrared behavior of that theory. In the simplest model which obeys such a constraint we find m 2 n,S ∼ (n + S). On the other hand, semiclassical Bohr-Sommerfeld quantization requires pdx ∼ n,