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Abstract
We evaluate the dynamic structure factor S(q ,?) of interacting one-dimensional spinless fermions with a nonlinear dispersion relation. The combined effect of the nonlinear dispersion and of the interactions leads to new universal features of S(q,?). The sharp peak S(q,?)?q?(?-uq), characteristic for the Tomonaga-Luttinger model, broadens up; S(q,?) for a fixed q becomes finite at arbitrarily large ?. The main spectral weight, however, is confined to a narrow frequency interval of the width ???q2/m . At the boundaries of this interval the structure factor exhibits power-law singularities with exponents depending on the interaction strength and on the wave number q.