  By applying the renormalization group method to two-coupled chains in the
Tomonaga model, the role of interchain hopping has been studied in the entire
energy region. The energy for a crossover from the perturbational regime to the
relevant regime becomes smaller than that of the interchain hopping due to
one-dimensional fluctuations of the mutual interaction. From the calculation of
response functions for charge density waves and superconducting states, the
phase diagram of dominant and subdominant states has been obtained in the plane
of mutual interactions with fixed energy.
