The non-linear excitations in 2D quantum lattice charged Bose-gas with an effective intersite attraction

The conditions of appearance of localized topological non-linear excitations in two-dimensional quantum lattice charged Bose-gas with an intersite attraction of bosons are analyzed. In the framework of quasi-spin formalism the possible solutions of non-linear equations of quasispin motion describes a coexisting of localized and delocalized charges participating in superfluid circular current. The numerical calculation of these equations is implemented and the main characteristics of soliton solutions (an energy and a number of localized bosons) are found.