  We report on results of theoretical study of non-uniform superconducting
states in quasi-one-dimensional systems, with attractive interactions and
Zeeman splitting between electron spins. Using bosonization to treat intrachain
electron-electron interactions, and a combination of renormalization group and
mean-field approximation to tackle interchain couplings, we obtain the phase
diagram of the system, and show that the transition between the uniform and
non-uniform superconducting phases is a continuous transition of the
commensurate-incommensurate type.
