Introducing an infinite spatial lattice with box length a, a systematic
expansion of the physical QCD Hamiltonian in \lambda = g^{-2/3} can be
obtained. The free part is the sum of the Hamiltonians of the quantum mechanics
of spatially constant fields for each box, and the interaction terms
proportional to \lambda^n contain n discretised spatial derivatives connecting
different boxes. As an example, the energy of the vacuum and the lowest scalar
glueball is calculated up to order \lambda^2 for the case of SU(2) Yang-Mills
theory.Comment: Talk given at the 6th International Workshop on "Critical Point and
Onset of Deconfinement (CPOD)", Dubna, Russia, 23-29 August 201