Renormalization-group study of competition between density waves and pairing in quasi-one-dimensional electron systems

We study crossover from the doped two-leg ladder system to a quasi-one-dimensional system by an inter-ladder oneparticle process and stability of the superconducting phase, using a renormalization-group method and differentiating the contributions from the particle-particle channel and those from the particle-hole channel. Effects of electron-2kF phonon and electron-4kF phonon couplings are also investigated.