  Motivated by the discovery of the anomalous metal state in thin film systems
and suggestions that coexistence of superconducting and metallic components is
crucial to the formation of the state, we study in this paper a model of mixed
metallic and superconducting grains coupled by electron tunneling - the
metallic grains are expected to become superconducting because of proximity
effect in a mean-field treatment of the model. When quantum fluctuations in
relative phases between different grains are taken into account, we show that
the proximity effect can be destroyed and the metallic and superconducting
grains become "insulating" with respect to each other when the charging energy
between grains are strong enough and tunneling between grains are weak enough,
in analogy to superconductor-insulator transition in pure superconducting
grains or metal-insulator transition in pure metallic grains. Based on this
observation, a physical picture of how the anomalous metal state may form is
proposed. An experimental setup to test our proposed physical picture is
suggested.
