Dr Bastian Brandt (University of Frankfurt)
We investigate the phase diagram of QCD at finite isospin chemical potential using 2+1 flavours of staggered fermions with physical quark masses at different lattice spacings and volumes. For high chemical potentials and low temperatures the confined phase shows a transition to the pion condensation phase. This phase is characterised by a proliferation of low modes that slow down the simulation considerably and necessitate the use of an infrared regulator. We discuss a novel strategy to determine the pion condensate in the limit of vanishing regulators. To investigate the convergence properties and the range of validity of the Taylor expansion method at a given order, we compare our results to the Taylor expansion for finite isospin chemical potential at 4 derivative order. This can serve as an important crosscheck for the Taylor expansion method at finite baryon chemical potential, where direct simulations are impossible due to the sign problem.
Dr Bastian Brandt (University of Frankfurt) Dr Gergely Endrodi (University of Frankfurt)