| We study the mechanism of directed energy transport for soliton ratchets. The energy flow appears due to the progressive motion of a soliton (kink) which is an energy carrier. However, the energy current formed by internal system deformations (the total field momentum) is zero. We show that the energy flow is realized via an inhomogenous energy exchange between the system and the external ac driving. We also discuss effects of spatial discretization and combination of ac and dc external drivings. |
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