Spin and charge excitations in incommensurate spin density waves

Collective excitations both for spin- and charge-channels are investigated in incommensurate spin density wave (or stripe) states on two-dimensional Hubbard model. By random phase approximation, the dynamical susceptibility \chi(q,\omega) is calculated for full range of (q,\omega) with including all higher harmonics components. An intricate landscape of the spectra in \chi(q,\omega) is obtained. We discuss the anisotropy of the dispersion cones for spin wave excitations, and for the phason excitation related to the motion of the stripe line. Inelastic neutron experiments on Cr and its alloys and stripe states of underdoped cuprates are proposed.