  Using the AdS/CFT correspondence, we calculate the vacuum decay rate for the
Schwinger effect in confining large $N_{c}$ gauge theories. The instability is
induced by the quark antiquark pair creation triggered by strong
electromagnetic fields. The decay rate is obtained as the imaginary part of the
Euler-Heisenberg effective Lagrangian evaluated from the D-brane action with a
constant electromagnetic field in holographic QCD models such as the
Sakai-Sugimoto model and the deformed Sakai-Sugimoto model. The decay rate is
found to increase with the magnetic field parallel to the electric field, while
it decreases with the magnetic field perpendicular to the electric field. We
discuss generic features of a critical electric field as a function of the
magnetic field and the QCD string tension in the Sakai-Sugimoto model.

High Energy Physics - Theory