Friedel oscillations of density of states in a one-dimensional Mott insulator and incommensurate charge-density wave or 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 incommensurate charge-density wave or superconductor) and at frequencies larger than the soliton spectral gap m. Their amplitude has a broad maximum at omega approximate to 3m, where m is the gap magnitude.