Superconducting phase of a two-chain Hubbard model

The exponent ${\mathit{K}}_{\mathrm{\rho }}$ and pair-field-correlation functions are calculated for a two-chain Hubbard model with an exact numerical diagonalization method. Our calculations clearly indicate that a superconducting phase appears for a wide range of Coulomb strength, where ${\mathit{K}}_{\mathrm{\rho }}$ and pair-field correlation functions are enhanced compared to the noninteracting system. The interchain pairing appears predominantly and thus our mechanism predicts an anisotropic superconductivity.