Comment on "Soliton ratchets induced by excitation of internal modes"

Niurka R. Quintero, Bernardo Sánchez-Rey, Jesús Casado-Pascual

Very recently Willis et al. [Phys. Rev. E {\bf 69}, 056612 (2004)] have used a collective variable theory to explain the appearance of a nonzero energy current in an ac driven, dam…