  We systematically study the chiral symmetry breaking and restoration in the
presence of a pure electric field in the Nambu--Jona-Lasinio (NJL) model at
finite temperature and baryon chemical potential. In addition, we also study
the effect of the chiral phase transition on the charged pair production due to
the Schwinger mechanism. For these purposes, a general formalism for parallel
electric and magnetic fields is developed at finite temperature and chemical
potential for the first time. In the pure electric field limit $B\rightarrow0$,
we compute the order parameter, the transverse-to-longitudinal ratio of the
Goldstone mode velocities, and the Schwinger pair production rate as functions
of the electric field. The inverse catalysis effect of the electric field to
chiral symmetry breaking is recovered. And the Goldstone mode is find to
disperse anisotropically such that the transverse velocity is always smaller
than the longitudinal one, especially at nonzero temperature and baryon
chemical potential. As expected, the quark-pair production rate is greatly
enhanced by the chiral symmetry restoration.
