Taste symmetry and QCD thermodynamics with improved staggered fermions

Understand

Taste symmetry violations in staggered fermion formulations correlate strongly with the cut-off (lattice spacing) dependence in thermodynamic quantities.

• Better taste symmetry on the lattice can be achieved either by decreasing the lattice spacing and going to larger temporal extent in finite-temperature calculations, or by further improving the action.
• The highly improved staggered quark (HISQ) action offers a further degree of improvement and substantially reduces taste violations.
• We report on our studies of the 2+1 flavor QCD thermodynamics with the HISQ/tree action.