Landau levels in QCD
Ferenc Pittler (Bonn)
In this talk we examine how Landau levels can be observed in QCD. In two dimensions the energy spectrum of free quarks exposed to a background magnetic field (B) shows Landau levels structure. If B is sufficiently large the weak interaction between the charged quarks only perturbs the Landau levels. In this talk, we check numerically with lattice simulations what happens when the strong interaction between quarks is turned on. Having understood what happens in two dimension, we turn our attention to the physically more interesting (and more complicated) 4d case. We evaluate various fermionic observables including the quark condensate and the spin polarization and check how the lowest Landau level contributes to them. Our results can be used to test the validity of low-energy models of QCD that make use of the lowest-Landau-level approximation.