  We reconstruct ghost and gluon spectral functions in 2+1 flavor QCD with
Gaussian process regression. This framework allows us to largely suppress
spurious oscillations and other common reconstruction artifacts by specifying
generic magnitude and length scale parameters in the kernel function. The
Euclidean propagator data are taken from lattice simulations with domain wall
fermions at the physical point. For the infrared and ultraviolet extensions of
the lattice propagators as well as the low-frequency asymptotics of the ghost
spectral function, we utilize results from functional computations in
Yang-Mills theory and QCD. This further reduces the systematic error
significantly. Our numerical results are compared against a direct real-time
functional computation of the ghost and an earlier reconstruction of the gluon
in Yang-Mills theory. The systematic approach presented in this work offers a
promising route towards unveiling real-time properties of QCD.
