Magnetic Catalysis of Chiral Symmetry Breaking: A Holographic Prospective

Figure 5

There is Zeeman splitting of the states due to the magnetic field. In the absence of the field, there are three straight lines emanating from the origin; these are split to form six curves. At zero bare quark mass (the end of the lowest curve), there is indeed a massless Goldstone mode. The straight lines correspond to the asymptotic AdS results.