  The notion that decoherence rapidly reduces a superposition state to an
incoherent mixture implicitly adopts a special representation, namely, the
representation of preferred (pointer) states (PS). For weak or strong
system-environment coupling, PS is known to be the energy eigenstates of the
system Hamiltonian or the eigenstates of the system-environment interaction
Hamiltonian. Via a simple dynamical model that simulates a two-level system
interacting with few other degrees of freedom as its environment, it is shown
that even for intermediate system-environment coupling, approximate PS may
still emerge from the coherent quantum dynamics of the whole system in the
absence of any thermal averaging. The found PS can also continuously deform to
expected limits for weak or strong system-environment coupling. Computational
results are also qualitatively explained. The findings should be useful towards
further understandings of decoherence and quantum thermalization processes.
