Non perturbative physics from NSPT: renormalons, the gluon condensate and all that

Understand

Numerical Stochastic Perturbation Theory (NSPT) enables very high order computations in Lattice Gauge Theories.

• We report on the determination of the gluon condensate from lattice QCD measurements of the basic plaquette.
• This is a long standing problem, which was eventually solved a few years ago in pure gauge.
• In this context NSPT is crucial: it is actually the only tool enabling the subtraction of the power divergent contribution associated to the identity operator in the OPE for the plaquette.