Dynamical fermions with fat links

We present and test a new method for simulating dynamical fermions with fat links. Our construction is based on the introduction of auxiliary but dynamical gauge fields and works with any fermionic action and can be combined with any fermionic updating. In our simulation we use an overrelaxation step which makes it effective. For four flavors of staggered fermions the first results indicate that flavor symmetry at a lattice spacing $a\approx 0.2\mathrm{fm}$ is restored to a few percent. With the standard action this amount of flavor symmetry restoration is achieved at $a\approx 0.07\mathrm{fm}.$ We estimate that the overall computational cost is reduced by at least a factor of 10.