  Frustrated spin systems can show phases with spontaneous breaking of
spin-rotational symmetry without the formation of local magnetic order. We
study the dynamic response of the spin-nematic phase of one-dimensional
spin-1/2 systems, characterized by slow large-distance decay of quadrupolar
correlations, by numerically computing one-spin and two-spin dynamical
structure factors at zero temperature using time-dependent density matrix
renormalization group methods. We interpret the results in terms of an
effective theory of gapped magnon excitations interacting with a
quasi-condensate of bound magnon pairs. This employs an extension of the
well-known Tomonaga-Luttinger liquid theory which includes the magnon states as
a mobile impurity. A good qualitative understanding of the characteristic
thresholds and their intensity in the structure factors is obtained this way.
Our results are useful in the interpretation of inelastic neutron scattering
and resonant inelastic x-ray scattering experiments.
