  We study the problem of stability of chiral states, also known as problem of
chirality, within the framework of a two-dimensional approximation of a
symmetric double-well potential. We show how the symmetry breaking of the
potential due to the molecular parity violation can stop the tunneling in a
coherent way, accordingly stabilize the chiral states. Then, we use the quantum
Brownian motion within a linear Lindblad-type equation to model how the
intermolecular interactions make the tunneling incoherent, thus inducing a
racemization by dephasing. Finally, we investigate the normal physical
conditions where the dephasing racemization does not suppress the effects of
the molecular parity violation, accordingly the molecular parity violation may
be observed experimentally.
