Overrelaxed heat-bath and Metropolis algorithms for accelerating pure gauge Monte Carlo calculations.

The lattice-gauge-theory generalization of Adler's over-relaxed heat-bath algorithm and an over-relaxed Metropolis update are shown to accelerate the decorrelation of physical observables. The heat-bath's microcanonical limit is especially attractive. Numerical tests for pure gauge SU(3) (${4}^{4}$ lattice, \ensuremath{\beta}=5.6) show, for example, that over-relaxation reduces the Polyakov-loop magnitude autocorrelation time for the Cabibbo-Marinari algorithm from 28 sweeps to 9, increasing computational efficiency threefold. These approaches are applicable to a large class of physical systems.