  The Low's theorem is applied to the soft gluon emission from heavy quark
scattering in quark-gluon plasma (QGP). The QGP is described by the dynamical
quasi-particle model (DQPM) which reproduces the EoS from lQCD at finite
temperature and chemical potential. We show that if the emitted gluon is soft
and of long wavelength, the scattering amplitude can be factorized into the
scattering part and the emission part and the Slavnov-Taylor identities are
satisfied in the leading order. Imposing a proper upper limit on the emitted
gluon energy, we obtain the scattering cross sections of charm quark as well as
the transport coefficients (momentum drag and diffusion) in the QGP with and
without gluon emission.
