  The self-energies of $\Delta$ isobar propagating in nuclear matter are
calculated using the finite-density QCD sum-rule methods. The calculations show
that the Lorentz vector self-energy for the $\Delta$ is significantly smaller
than the nucleon vector self-energy. The magnitude of the $\Delta$ scalar
self-energy is larger than the corresponding value for the nucleon, which
suggests a strong attractive net self-energy for the $\Delta$; however, the
prediction for the scalar self-energy is very sensitive to the density
dependence of certain in-medium four-quark condensate. Phenomenological
implications for the couplings of the $\Delta$ to the nuclear scalar and vector
fields are briefly discussed.
