  We make use of the Nambu-Jona-Lasinio (NJL) formalism and real-time
finite-temperature field theory to calculate hadronic current correlation
functions in the deconfined phase of quantum chromodynamics (QCD). We consider
both pseudoscalar and vector currents and compare our results with those
obtained in lattice simulations of QCD. Our results are similar to those
obtained in the lattice simulations for $T=1.5 T_c$, where $T_c$ is the
temperature of the confinement-deconfinement transition. For $T=3.0 T_c$ our
results do not exhibit the resonances obtained from the lattice simulations.
However, the errors presented for the lattice results are large and it is
possible that our results at $T=3.0 T_c$ are consistent with the lattice
results when these errors are taken into account. Since the method used in the
lattice analysis to obtain the spectral functions requires assumptions about
the likelihood of a particular form for the spectral function, we believe our
calculations will be useful to researchers who wish to calculate hadronic
current correlation functions at finite temperature using lattice-based
methods. Our model makes use of temperature-dependent coupling constants for
the NJL model. We present an argument that such temperature dependence is
necessary, if the results of the model are to be consistent with what is known
concerning QCD thermodynamics.
