| Many low dimensional strongly correlated systems have very rich phase diagrams and various interesting symmetry breaking phases. Two such systems are considered in this thesis. The first one is 2-dimensional disordered interacting electronic system. It is shown that in unitary case, no matter how weak the disorder and the interaction are, there always exists an instability of diffusive Fermi liquid fixed point, and this instability will lead to a ferromagnetic state, the physics of the ferromagnetic state is studied, a phase diagram for 2 + epsilon dimensions is also proposed. The second problem is the d-density wave state which is related to the pseudogap region of the high T c cuprates. Various in plane transport properties, such as thermal and electrical conductivities, Hall number, are calculated. It is shown that these transport properties will help identify the underlying phases. |
