  We study the time evolution of the expectation value of the anharmonic
oscillator coordinate in a coherent state as a toy model for understanding the
semiclassical solutions in quantum field theory. By using the deformation
quantization techniques, we show that the coherent state expectation value can
be expanded in powers of $\hbar$ such that the zeroth-order term is a classical
solution while the first-order correction is given as a phase-space Laplacian
acting on the classical solution. This is then compared to the effective action
solution for the one-dimensional $\f^4$ perturbative quantum field theory. We
find an agreement up to the order $\l\hbar$, where $\l$ is the coupling
constant, while at the order $\l^2 \hbar$ there is a disagreement. Hence the
coherent state expectation values define an alternative semiclassical dynamics
to that of the effective action. The coherent state semiclassical trajectories
are exactly computable and they can coincide with the effective action
trajectories in the case of two-dimensional integrable field theories.
