In this work, we incorporate quantum physics to develop analytical models for doped and undoped, thin-body DG FETs. An explicit current model has been introduced in terms of both source and drain charge densities at which hole and electron quasi-Fermi level or IMREFs are defined. Our compact models, with no fitting parameters, give good predictions of the quantum volume inversion charge and drain current. These models have been verified with self-consistent results form numerical calculations of the coupled Poission-Schrodinger equations. An important consequence of new compact models can be inserted into simulation programs such as SPICE, thus overcoming limitations when only classical physics is used.