Spontaneous generation of localCPviolation and inverse magnetic catalysis

Abstract

In the chiral symmetric phase, the polarized instanton-anti-instanton molecule pairing induces a nontrivial repulsive interaction in the iso-scalar axial-vector channel. As a consequence, one unusual property is observed that in the chiral restoration phase, there is a first order phase transition for the spontaneous generation of local CP violation and chirality imbalance. Furthermore, it is found that external magnetic fields will lower the critical temperature for the local CP-odd phase transition and catalyze the chirality imbalance, which destroys the chiral condensate with pairing quarks between different chiralities. A reasonable strength of the repulsive interaction in the iso-scalar axial-vector channel can naturally explain the inverse magnetic catalysis around the critical temperature under external magnetic fields.

Study of the QCD phase diagram with a nonzero chiral chemical potential

“…For instance, the authors of papers [32][33][34][35][36] have predictied that the transition shifts to smaller temperatures as µ 5 increases. At the same time, some of the results obtained in papers [37,38] imply that the transition shifts to larger temperatures as µ 5 increases.…”

Two-color QCD with non-zero chiral chemical potential

“…frozen) by a non-zero chiral chemical potential. In this setting, the modification of the phase diagram by the chiral chemical potential µ 5 has been studied mainly by means of effective models [21][22][23][24][25][26][27], the predictions of which will later be compared with our results.…”

Chiral phase transition of QCD with N f = 2 + 1 flavors from holography

“…The qualitative results for SU (2) and SU(3) cases are in good agreement with the current understanding from figure 1(a): for two flavor case it starts from a second order phase transition and turns to be crossover at any finite quark mass while for three flavor case it starts from a first order phase transition and only at sufficient large quark masses it turns to be crossover. Furthermore, in [67], we extend these studies to finite magnetic field, and find that it can provide good description on inverse magnetic catalysis effect, which was discovered in lattice QCD [68,69] and studied in other methods [70][71][72][73][74][75][76][77][78][79][80] recently. However, the cases when m u/d = m s have not been examined in this model.…”