Deconfinement Phase Transition with External Magnetic Field in the Friedberg–Lee Model

The deconfinement phase transition with external magnetic field is investigated in the Friedberg–Lee model. We expand the potential around the two local minima of the first-order deconfinement phase transition and extract the ground state of the system in the frame of functional renormalization group. By solving the flow equations we find that the magnetic field displays a catalysis effect and it becomes more difficult to break through the confinement.