Reconstructing QCD Spectral Functions with Gaussian Processes

Understand

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.