Testing a Topology Conserving Gauge Action in QCD
  We study lattice QCD with a gauge action, which suppresses small plaquette values. Thus the MC history is confined to a single topological sector over a significant time, while other observables are decorrelated. This enables the cumulation of statistics with a specific topological charge, which is needed for simulations of QCD in the $\epsilon$-regime. The same action may also be useful for simulations with dynamical quarks. The update is performed with a local HMC algorithm. 
S. Shcheredin, W. Bietenholz, K. Jansen, K.-I. Nagai, S. Necco and L.   Scorzato