  The nonadiabatic quantum tunneling picture, which may be called the many-body
Schwinger-Landau-Zener mechanism, for the dielectric breakdown of Mott
insulators in strong electric fields is studied in the one-dimensional Hubbard
model. The tunneling probability is calculated by a metod due to
Dykhne-Davis-Pechukas with an analytical continuation of the Bethe-ansatz
solution for excited states to a non-Hermitian case. A remarkable agreement
with the time-dependent density matrix renormalization group result is
obtained.
