We study the response of a highly excited 1D gas with pointlike interactions
to a periodic modulation of the coupling constant. We calculate the
corresponding dynamic structure factors and show that their low-frequency
behavior differs dramatically for integrable and nonintegrable models.
Nonintegrable systems are sensitive to excitations with frequencies as low as
the mean level spacing, whereas much higher frequencies are required to excite
an integrable system. This effect can be used as a probe of integrability for
mesoscopic 1D systems and can be observed experimentally by measuring the
heating rate of a parametrically excited gas.Comment: Published version, 4 pages, 2 figure