Conservative Crank–Nicolson-type and compact finite difference schemes for modeling the Schrödinger equation with point nonlinearity

Abstract

In this paper, we propose conservative Crank–Nicolson-type and compact finite difference schemes for the nonlinear Schrödinger equation with point nonlinearity. To construct these schemes, we first transform the point nonlinearity into an interface condition, then decompose the computational domain along the interface into two subregions with a jump condition. Different discretization approximations of the jump condition lead to different numerical schemes. For the Crank–Nicolson finite difference scheme, we prove its unconditional mass conservation and energy conservation. Some numerical examples are also presented to illustrate the accuracy and efficiency of our proposed schemes.