next up previous
Next: Gauss' Law and Up: No Title Previous: Motion on the

Classical Lattice Gauge Theory

Lattice gauge theory, both in its Euclidean and Hamiltonian version, has been described in the literature exhaustingly[6]. Here we deal only with the classical Hamiltonian SU(2) theory specified by a Hamilton function, which describes a coupled system of quaternionic pendulums

 

where the summation runs over all oriented links of the three dimensional cartesian lattice, and the usual magnetic energy form

containing a summation of traces of oriented products of four group elements U on links circumventing a plaquette --- an elementary square of the lattice --- is rewritten as a sum over all links of the scalar product of link variables U with their complement V defined by the sum of all triple products of oriented link group elements closing a plaquette with the chosen link. Since this way all plaquettes are counted four times in the sum --- because each plaquette is surrounded by four links --- a division by 4 completes the definition of V. This is no more a group element, because its length is no more unity. It can, however, be written as its quaternionic length multiplied by a group element. This way we describe a system of coupled pendulums each of which feels a "gravity" caused by some neighbouring ones.

The equations of motion following from the above Hamiltonian has to be approximated by a Type III algorithm described in eq.( 39 ) with an additional force ,

 

with the Lagrange multipliers

This update equations conserve then the norm, the orthogonality and the Noether charge calculated via the respective half integer time definitions. The energy, however, is not conserved anymore locally.