Ground state structure and conductivity of quantum wires of infinite length and finite width

We have studied the ground state structure of quantum strips within the local spin-density approximation, for a range of electronic densities between similar to 5x10(4) and 2x10(6)cm(-1) and several strengths of the lateral confining potential. The results have been used to address the conductance G of quantum strips. At low density, when only one subband is occupied, the system is fully polarized and G takes a value close to 0.7(2e(2)/h), decreasing with increasing electron density in agreement with experiments. At higher densities the system becomes paramagnetic and G takes a value near (2e(2)/h), showing a similar decreasing behavior with increasing electron density. In both cases, the physical parameter that determines the value of the conductance is the ratio K/K-0 of the compressibility of the system to the free one.