Dispersion of the pi resonance in the superconducting state of the cuprates - art. no. 100502

We study the dispersion of tr resonance in the superconducting state within the projected SO(5) model [S.C. Zhang et al., Phys. Rev. B 60, 13 070 (199 9)]. Away from the commensurate momentum, the propagation of the pi resonan ce creates phase flips in the superconducting order parameter. This frustra tion effect leads to a strong dressing of the pi resonance and a downward d ispersion away from the commensurate wave vector. Based on these results, w e argue that the commensurate resonance and incommensurate magnetic fluctua tions in the cuprates are continuously connected.