Theoretical framework for quasi-one dimensional systems

To date, understanding the physics of one-dimensional electrons has been the focus of much theoretical and experimental efforts. In the organic materials and in nanoscopic systems, one-dimensional effects could be easily searched. However, among all these systems, the organic conductors remain a unique challenge. This review makes a presentation of the main theoretical concepts for electrons in one dimension and briefly discusses how these concepts are relevant to understanding the quasi-one-dimensional organic conductors. Topics discussed include effects of interactions in the normal phase, effects of magnetic fields (field induced spin density waves), ordered states such as the spin-Peierls, charge and spin density waves, and the superconducting phases.