Infrahumps detected in Kepler light curve of V1504 Cygni

We present a power spectral density analysis of the short cadence Kepler data for the cataclysmic variable V1504 Cygni. We identify three distinct periods: the orbital period (1.669\pm0.005 hours), the superhump period (1.733\pm0.005 hours), and the infrahump period (1.628\pm0.005 hours). The results are consistent with those predicted by the period excess-deficit relation.