  In this contribution we investigate the phase diagram of QCD in the presence
of an isospin chemical potential. To alleviate the infrared problems of the
theory associated with pion condensation, we introduce the pionic source as an
infrared regulator. We discuss various methods to extrapolate the results to
vanishing pionic source, including a novel method based on the singular value
spectrum of the massive Dirac operator, a leading-order reweighting and a
spline Monte-Carlo fit. Our main results concern the phase transition boundary
between the normal and the pion condensation phases and the
chiral/deconfinement transition temperature as a function of the chemical
potential. In addition, we perform a quantitative comparison between our direct
results and a Taylor-expansion obtained at zero chemical potential to assess
the applicability range of the latter.
