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Abstract |
Dynamical symmetry breaking (DSB) is a well known phenomenon in several areas of physics leading to a mass (gap) generation for fermions. The presence of an external magnetic field can be a strong catalyst for the DSB effect, leading to the generation of a dynamical mass for fermions even by very weak attractive interactions - the phenomenon called the magnetic catalysis. For example, in an external magnetic field, the critical value of the Nambu–Jona-Lasinio coupling for the dynamical fermion mass generation is reduced to zero. The effect is primarily due to the dimensional reduction in the dynamics of fermion pairing in a magnetic field. The lowest Landau level plays the crucial role in catalyzing spontaneous symmetry breaking, its role is similar to that of the Fermi surface in the BCS theory of superconductivity. We consider the phenomenon of magnetic catalysis in various models of quantum field theory with short-range and long-range interactions. In application to graphene, magnetic catalysis can be used to explain the observation of quantum Hall plateaus in strong magnetic fields beyond the standard anomalous sequence of filling factors. |
