N=2 N=4 Supersymmetric Born-Infeld Theories from Non Linear Realizations

SStarting from nonlinear realizations of the partially broken central-charge extended N=4 and N=8 Poincar\'e supersymmetries in D=4, we derive the superfield equations of N=2 and N=4 Born-Infeld theories. The basic objects are the bosonic Goldstone N=2 and N=4 superfields associated with the central charge generators. By construction, the equations are manifestly N=2 and N=4 supersymmetric and enjoy covariance under another nonlinearly realized half of the original supersymmetries. They provide a manifestly worldvolume supersymmetric static-gauge description of D3-branes in D=6 and D=10. For the N=2 case we find, to lowest orders, the equivalence transformation to the standard N=2 Maxwell superfield strength and restore, up to the sixth order, the off-shell N=2 Born-Infeld action with the second hidden N=2 supersymmetry.