  An effective low energy field theory is developed for a system of two chains.
The main novelty of the approach is that it allows to treat generic intrachain
repulsive interactions of arbitrary strength. The chains are coupled by a
direct tunneling and four-fermion interactions. At low energies the individual
chains are described as Luttinger liquids with an arbitrary ratio of spin $v_s$
and charge $v_c$ velocities. A judicious choice of the basis for the decoupled
chains greatly simplifies the description and allows one to separate high and
low energy degrees of freedom. In a direct analogy to the bulk cuprates the
resulting effective field theory distinguishes between three qualitatively
different regimes: (i) small doping ($v_c << v_s$), (ii) optimal doping ($v_s
\approx v_c$) and (iii) large doping ($v_s << v_c$). I discuss the excitation
spectrum and derive expressions for the electron spectral function which turns
out to be highly incoherent. The degree of incoherence increases when one
considers an array of ladders (stripe phase).

Strongly Correlated Electrons