Localised nonlinear modes in the PT-symmetric double-delta well Gross-Pitaevskii equation

Abstract

We construct exact localised solutions of the PT-symmetric Gross-Pitaevskii equation with an attractive cubic nonlinearity. The trapping potential has the form of two $\delta$-function wells, where one well loses particles while the other one is fed with atoms at an equal rate. The parameters of the constructed solutions are expressible in terms of the roots of a system of two transcendental algebraic equations. We also furnish a simple analytical treatment of the linear Schr\"odinger equation with the PT-symmetric double-$\delta$ potential.