Dynamics of DNA breathing in the Peyrard-Bishop model with damping and external force

The impact of damping effect and external forces to the DNA breathing is investigated within the Peyrard-Bishop model. In in the continuum limit, the dynamics of the breathing of DNA is described by the forced-damped nonlinear Schrodinger equation and studied by means of variational method. The analytical solutions are obtained for special cases. It is shown that the breather propagation is decelerated in the presence of damping factor without the external force, while the envelope velocity and the amplitude increase significantly with the presence of external force. It is particularly found that the higher harmonic terms are enhanced when the periodic force is applied. It is finally argued that the external force accelerates the DNA breathing.