Computer algorithms for Euclidean lattice gauge theory calculations
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
The computer algorithm devised by K. Decker  for the calculation of strong coupling expansions in Euclidean lattice gauge theory is reviewed. Various shortcomings of this algorithm are pointed out and an improved algorithm is developed. The new algorithm does away entirely with the need to store large amounts of information, and is designed in such a way that memory useage is essentially independant of the order to which the expansion is being calculated. A good deal of the redundancy and double handling present in the algorithm of ref.  is also eliminated. The algorithm has been used to generate a 14th order expansion for the energy of a glue ball with non-zero momentum in Z₂ lattice gauge theory in 2+1 dimensions. The resulting expression is analysed in order to study the restoration of Lorentz invariance as the theory approaches the continuum. A description is presented of the alterations required to extend the algorithm to calculations in 3+1 dimensions. An eighth order expansion of the z₂ mass gap in 3+1 dimensions has been calculated. The eighth order term differs from a previously published result.