Asymmetric kinks: stabilization by entropic forces.
Asymmetric kinks bridging two adjacent potential valleys of equal depth but different curvature are unstable against phonon modes. When coupled to a heat bath, a kink-bearing string tends to cross over into the shallower valley; kinks are thus predicted to drift in the appropriate direction with velocity proportional to the temperature, in close agreement with numerical simulation. When contrasted by a mechanical bias, these entropic forces give rise to a rich phenomenology that includes configurational phase transitions, double-kink dissociation, and noise-directed signal transmission.
Costantini
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Istituto Nazionale di Fisica della Materia, Universitá di Camerino, I-62032 Camerino, Italy.
Marchesoni
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