  Exact results for the Jarzynski equality are derived for Ising spin glass
models. The Jarzynski equality is an equality that connects the work in
nonequilibrium and the difference between free energies. The work is performed
in switching an external parameter of the system. As the Ising spin glass
models, the +-J model and the Gaussian model are investigated. For the +-J
model and the Gaussian model, we derive exact lower bounds of the exponentiated
work for investigating the ferromagnetic phases and the multicritical points,
and derive rigorous relations between the exponentiated work which have
different quenched random configurations. For the Gaussian model, we derive the
exact exponentiated work for investigating the spin glass phase. Exact results
for the infinite-range models are also obtained. The present results are
obtained by using a gauge symmetry, and are related to points on the Nishimori
lines which are special lines in the phase diagrams. The present results do not
depend on any lattice shape, and a part of the present results instead depends
on the number of nearest-neighbor pairs in the whole system.
