The quark mass gap in strong magnetic fields

Kojo T, Su N. The quark mass gap in strong magnetic fields. Nuclear Physics A. 2014;931:763-768.Quarks in strong magnetic fields (vertical bar eB vertical bar >> Lambda(2)(QCD) similar to 0.04 GeV2) acquire enhanced infrared phase space proportional to vertical bar eB vertical bar. Accordingly they provide larger chiral condensates and stronger backreactions to the gluon dynamics. Confronting theories with lattice data at various values of vertical bar eB vertical bar, one can test theoretical ideas as well as validity of various approximations, domain of applicability of the effective models, and so on. The particularly interesting findings on the lattice are inverse magnetic catalysis and linear growth of the chiral condensate as a function of vertical bar eB vertical bar, which pose theoretical challenges. In this talk we propose a scenario to explain both phenomena, claiming that the quark mass gap should stay at around similar to Lambda(QCD), instead of similar to vertical bar eB vertical bar(1/2) which has been supposed from dimensional arguments and/or effective model calculations. The contrast between infrared and ultraviolet behaviors of the interaction is a key ingredient to obtain the mass gap of similar to Lambda(QCD). (C) 2014 Elsevier B.V. All rights reserved