QCD in an external magnetic field

One of the striking features of QCD, the theory of strong
interactions, is the confinement of strongly charged objects. Its
fundamental fields, the quarks and gluons, do not appear as asymptotic
states but are bound in hadrons such as the proton. Interestingly,
the most striking experimental evidence of this phenomenon is the
absence of objects with fractional electric charges in nature.

Combinations of QCD and electrodynamical effects also gained
prominence recently with the observation of the so-called chiral
magnetic effect at the Brookhaven National Laboratory where a magnetic
field may induce local parity violations in QCD matter. I will report
on recent work, numerically simulating QCD in Lattice regularization,
in the presence of an external (electro-)magnetic field. This affects
the phase transition temperature, with possible implications for heavy
ion collision experiments and the early universe.