Four-Quark Binding Energies from SU(2) Lattice Monte Carlo
  Energies of four-quark systems have been extracted in a static quenched SU(2) lattice Monte Carlo calculation for six different geometries, both planar and non-planar, with $\beta=2.4$ and lattice size $16^3\times 32$. In all cases, it is found that the binding energy is greatly enhanced when the four quarks can be partitioned in two ways with comparable energies. Also it is shown that the energies of the four-quark states cannot be understood simply in terms of two-quark potentials. 
A.M.Green, C.Michael and M.E.Sainio