2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/16485We combine the results of terahertz time-domain spectroscopy with far-infrared transmission and reflectivity to obtain the conductivity of SrRuO_3 over an unprecedented continuous range in frequency, allowing us to characterize the approach to zero frequency as a function of temperature. We show that the conductivity follows a simple phenomenological form, with an analytic structure fundamentally different from that predicted by the standard theory of metals.4 pages, 3 figures, revtex4b4Strongly Correlated ElectronsSuperconductivitytext