Integrability and exact solution of correlated hopping multi-chain electron systems

Exact quantum integrability is established for a class of multi-chain electron models with correlated hopping and spin models with interchain interactions, by constructing the related Lax operators and R-matrices through twisting and gauge transformations. Exact solution of the eigenvalue problem for commuting conserved quantities of such systems is achieved through Algebraic Bethe ansatz, on the examples of Hubbard and t-J models with correlated hopping. Our systematic construction identifies the integrable subclass of such known solvable models and also generates new systems including the generalized t-J models. At the same time it makes proper correction to a well known model and resolves recent controversies regarding the equivalence and solvability of some known models.