摘要

We develop a Riemann-Hilbert approach to the Cauchy problem on the line for a new type of coupled nonlinear SchrOdinger (CNLS) equations iq(1,t) + q(1,xx) + 2(vertical bar q(1)vertical bar(2) - 2 vertical bar q(2)vertical bar(2))q(1) - 2q(2)(2)q(1)* = 0 iq(2,t) + q(2,xx) + 2(2 vertical bar q(1)vertical bar(2) - vertical bar q(2)vertical bar(2))q(2) + 2q(1)(2)q(2)* = 0 This approach allows us to give a representation of the solution to the Cauchy problem of the CNLS equations in terms of the solution of a 4 x 4 Riemann-Hilbert problem formulated in the complex k-plane. Due to the energy conservation law of above system is integral(+infinity)(-infinity) (vertical bar q(1)vertical bar(2) - vertical bar q(2)vertical bar(2))dx, it is difficult to obtain a solution for this system by using the energy estimate method of PDE's. Therefore, this approach efficiently provides a new way in studying the nonlinear problems that PDE's theory can't solve. Furthermore, this representation is then used for retrieving the soliton solutions.