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This paper explores nonlinear Schrödinger solitons influenced by spatially periodic and time-dependent forces. Utilizing collective coordinate theory, we highlight how solitons approach steady-state solutions under specific initial conditions and damping scenarios. We analyze the stability of these solitons using the Vakhitov-Kolokolov and Pego-Weinstein criteria, focusing on situations with both oscillatory solutions and unidirectional motion. The findings provide insights into the mechanisms governing soliton behavior in the presence of periodic forces, contributing to the broader understanding of soliton dynamics.
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NonlinearSchrödingersolitonsunderspatio-temporal forces withNiurka R. Quintero, Sevilla, and Alan Bishop, Los Alamos arXiv:0907.2438v1
2. Collective Coordinate(CC) Theory Notice: velocityisconstant, althoughforceisperiodic, andphaseisconstant
Ifinitialconditions (IC) nearsteady-statesolutionanddampingbelowcriticalvalue, solitonsalwaysapproachthesteady-statesolution If IC not closetosteady-statesolutionor/anddampingtoo large, thesolitonvanishes, i.e. amplitudeandenergy -> zero, width -> infinity
Case 1b) constant, spatiallyperiodicforce f(x) = exp(iKx), nodamping Stationarysolutions In regionaroundthestationarysolution, thereareoscillatorysolutions Stability? Vakhitov-Kolokolovcriterion valid onlyforstationarysolutions. Try Pego-Weinstein stabilitycriterion : dP/dV > 0, where P and V aresolitonmomentumandvelocity
If „stabilitycurve“ P(V) hasno negative slope, solitonisstable. Notice: unidirectionalmotion, on theaverage, althoughspatialaverageofforcevanishes!
4. Summary Case 1.) constant , spatiallyperiodicforce, nodamping: Oscillatorysolutions, stabilityandlifetimepredictedbyPego-Weinstein-criterion. Unidirectionalmotion , althoughspatialaverageofforcevanishes Withdamping, solitonsapproachsteady-statesolution. Case 2.) acdrivingforce, nodamping: All CCs oscillatewith 3 frequencies: intrinsic, drivingandverylowfrequency Case 3.) biharmonicdrivingforce: Ratcheteffectforunderdampedcase