Asymptotic stability of harmonic maps under the Schrödinger flow
Gustafson, Stephen ; Kang, Kyungkeun ; Tsai, Tai-Peng
Duke Math. J., Tome 141 (2008) no. 1, p. 537-583 / Harvested from Project Euclid
For Schrödinger maps from $\mathbb{R}^2\times\mathbb{R}^+$ to the $2$ -sphere $\mathbb{S}^2$ , it is not known if finite energy solutions can form singularities (blow up) in finite time. We consider equivariant solutions with energy near the energy of the two-parameter family of equivariant harmonic maps. We prove that if the topological degree of the map is at least four, blowup does not occur, and global solutions converge (in a dispersive sense, i.e., scatter) to a fixed harmonic map as time tends to infinity. The proof uses, among other things, a time-dependent splitting of the solution, the generalized Hasimoto transform, and Strichartz (dispersive) estimates for a certain two space--dimensional linear Schrödinger equation whose potential has critical power spatial singularity and decay. Along the way, we establish an energy-space local well-posedness result for which the existence time is determined by the length scale of a nearby harmonic map
Publié le : 2008-12-01
Classification:  35Q55,  35B40
@article{1229349904,
     author = {Gustafson, Stephen and Kang, Kyungkeun and Tsai, Tai-Peng},
     title = {Asymptotic stability of harmonic maps under the Schr\"odinger flow},
     journal = {Duke Math. J.},
     volume = {141},
     number = {1},
     year = {2008},
     pages = { 537-583},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1229349904}
}
Gustafson, Stephen; Kang, Kyungkeun; Tsai, Tai-Peng. Asymptotic stability of harmonic maps under the Schrödinger flow. Duke Math. J., Tome 141 (2008) no. 1, pp.  537-583. http://gdmltest.u-ga.fr/item/1229349904/