LAUSR

We investigate analytically and numerically whether an optimally designed defect structure can significantly reduce the threshold for breather train generation by almost two orders of magnitude in a sine-Gordon chain. By optimizing the parameters of defects based on a variational approach, we show that the decoupling of in-phase and antiphase branches allows us to independently minimize the driving threshold and reach the goal of emission of high-amplitude and well-formed breathers by an ultraweak driving. These results not only provide an optimal way for highly controllable and efficient emission of breathers, but also provide some insights into the mechanism of breather excitations in such processes as the DNA-protein interaction during transcription.