Dynamical response function of 2kF-SDW for the Tomonaga-Luttinger model

The response function, chi(SDW)(R)(q, omega), Of 2k(F)-SDW (spin density wave) with momentum 2k(F) + q and frequency omega has been studied for the Tomonaga-Luttinger model by taking account of the momentum cutoff of the repulsive interaction where k(F) is the Fermi momentum. We have found that Im chi(SDW)(R)(q,omega) as a function of omega exhibits a novel peak located at an energy with the Fermi velocity in addition to two peaks at energies with the renormalized velocities, v(rho) and v(sigma) corresponding to charge and spin excitations. Temperature dependence of Im chi(SDW)(R)(q, omega) is calculated to show that the spin fluctuation is dominant at low temperatures for the strong interaction and that the peak vanishes at high temperatures leading to a crossover into that in the absence of interaction.