Friedel oscillations of Density of States in a one-dimensional Mott insulator and Incommensurate Charge Density Wave/Superconductor

Oscillations of local density of states generated by a single scalar impurity potential are calculated for one-dimensional systems with dynamically generated charge or spin gap. At zero temperature the oscillations develop at finite wave vector ($\pi$ for the Mott insulator and $2k_F$ for ICDW/SC) and at frequencies larger than the soliton spectral gap $m$. Their amplitude has a broad maximum at $\omega \approx 3m$, where $m$ is the gap magnitude.