  We derive a model of quantum-classical hybrids for a simplified model of
quantum electrodynamics in the framework of the stochastic variational method.
In this model, charged particle trajectories are affected by the interaction
with quantized electromagnetic fields, and this quantum-classical interaction
induces a displacement current. We further investigate a geometric phase in the
wave functional of the gauge field configuration, which is induced by adiabatic
motions of the charged particles. This phase contains the quantum-classical
backreaction effect and usual Berry's phase is reproduced in the vanishing
limit of the fluctuation of the charged particle trajectories.
