Towards Highly Improved Quark Actions
  We describe two ideas useful in the construction of highly improved quark actions for simulations on coarse lattices:   (1) Field transformations to solve the doubler problem without destroying tree-level improvement for on- or off-shell quantities.   (2) Anisotropic lattices with smaller temporal than spatial lattice spacing. We present first simulation results for the quenched light hadron and charmonium spectra obtained with a D234 action on anisotropic lattices. 
M. G. Alford, T. R. Klassen and G. P. Lepage