The vortex system is a model system of interacting elastic objects in disordered media. Recently it
was found that it can be trapped in different robust dynamical states characterized by the degree
of mobility, depending on the local thermo-magnetic history of the sample. When vortices are
"shaken" by a temporarily symmetric ac field they are driven into an easy-to-move
structure but, on the contrary, when the ac field is temporarily asymmetric, they are driven into a
more pinned state. The effective pinning potential wells that control the vortex motion inside the
pinning sites can also be tuned by the "shaking" procedure, and deeper wells correlate
with less mobile dynamical states.
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