title: Reversible soliton motion.
abstract: We show that spatial solitons on either phase- or amplitude-modulated backgrounds can change their direction of motion according to the modulation frequency. A soliton may, therefore, move up or down phase gradients or remain motionless regardless of where it is in relation to the background modulation. The general theory is in good agreement with numerical results in a variety of nonlinear systems.
authors.affiliation: Department of Physics, University of Strathclyde, 107 Rottenrow, Glasgow G4 ONG, Scotland, United Kingdom. andrew@phys.strath.ac.uk
authors.forename: A J
authors.initials: AJ
authors.lastname: Scroggie
authors.forename: J
authors.initials: J
authors.lastname: Jeffers
authors.forename: G
authors.initials: G
authors.lastname: McCartney
authors.forename: G-L
authors.initials: GL
authors.lastname: Oppo