Probing the QCD vacuum with an abelian chromomagnetic field: A study within an effective model

摘要

We study the response of the QCD vacuum to an external abelian chromomagneticfield in the framework of a non local Nambu-Jona Lasinio model with thePolyakov loop. We use the Lattice results on the deconfinement temperature ofthe pure gauge theory to compute the same quantity in the presence of dynamicalquarks. We find a linear relationship between the deconfinement temperaturewith quarks and the squared root of the applied field strength, $gH$, inqualitative (and to some extent also quantitative) agreement with existingLattice calculations. On the other hand, we find a discrepancy on theapproximate chiral symmetry restoration: while Lattice results suggest thedeconfinement and the chiral restoration remain linked even at non-zero valueof $gH$, our results are consistent with a scenario in which the twotransitions are separated as $gH$ is increased.