A lattice model related to the nonlinear Schroedinger equation

This is a historical note. In 1981 we constructed a discrete version of quantum nonlinear Schroedinger equation. This led to our discovery of quantum determinant: it appeared in construction of anti-pod (11). Later these became important in quantum groups: it describes the center of Yang-Baxter algebra. Our paper was published in Doklady Akademii Nauk vol 259, page 76 (July l981) in Russian language.