Nodelessd-wave pairing in a two-layer Hubbard model

Abstract
Pairing correlations in a two-layer Hubbard model are studied using (1) an Eliashberg-like approximation for the exchange of spin fluctuations and (2) quantum Monte Carlo simulations. A possible pair structure in which the gap has one sign on the bonding and the opposite sign on the antibonding Fermi surface is found. Some implications of this for the transport properties of the cuprate superconductors are discussed.