We calculate the optical conductivity in a clean system of quasiparticles
coupled to charge-ordering collective modes. The absorption induced by these
modes may produce an anomalous frequency and temperature dependence of
low-energy optical absorption in some cuprates. However, the coupling with
lattice degrees of freedom introduces a non-universal energy scale leading to
scaling violation in low-temperature optical conductivity.Comment: Proceedings of M2S 2006. To appear in Physica