  We consider spin- and density-related properties of single-particle states in
a one-dimensional system with random spin-orbit coupling. We show that the
presence of an additional Zeeman field $\Delta$ induces both nonlinear spin
polarization and delocalization of states localized at $\Delta=0$,
corresponding to a random macroscopic analogue of the Paschen-Back effect.
While the conventional Paschen-Back effect corresponds to a saturated
$\Delta-$dependence of the spin polarization, here the gradual suppression of
the spin-orbit coupling effects by the Zeeman field is responsible both for the
spin saturation and delocalization of the particles.

Quantum Gases