Four-fermion interactions and the chiral symmetry breaking in an external magnetic field

Understand

We investigate the chiral symmetry and its spontaneous breaking at finite temperature and in an external magnetic field with four-fermion interactions of different channels.

• Quantum and thermal fluctuations are included within the functional renormalization group approach, and properties of the set of flow equations for different couplings, such as its fixed points, are discussed.
• It is found that external parameters, e.g.
• the temperature and the external magnetic field and so on, do not change the structure of the renormalization group flows for the couplings.