  Using holography, we discuss the effects of an external static electric field
on the D3/D-instanton theory at zero-temperature, which is a quasi-confining
theory, with confined quarks and deconfined gluons. We introduce the quarks to
the theory by embedding a probe D7-brane in the gravity side, and turn on an
appropriate $U(1)$ gauge field on the flavor brane to describe the electric
field. Studying the embedding of the D7-brane for different values of the
electric field, instanton density and quark masses, we thoroughly explore the
possible phases of the system. We find two critical points in our
considerations. We show that beside the usual critical electric field present
in deconfined theories, there exists another critical field, with smaller
value, below which no quark pairs even the ones with zero mass are produced and
thus the electric current is zero in this (insulator) phase. At the same point,
the chiral symmetry, spontaneously broken due to the gluon condensate, is
restored which shows a first order phase transition. Finally, we obtain the
full decay rate calculating the imaginary part of the DBI action of the probe
brane and find that it becomes nonzero only when the critical value of the
electric field is reached.
