English

Renormalization and blow up for wave maps from $S^2\times \RR$ to $S^2$

Analysis of PDEs 2012-06-14 v3

Abstract

We construct a one parameter family of finite time blow ups to the co-rotational wave maps problem from S2×\RRS^2\times \RR to S2,S^2, parameterized by ν(1/2,1].\nu\in(1/2,1]. The longitudinal function u(t,α)u(t,\alpha) which is the main object of study will be obtained as a perturbation of a rescaled harmonic map of rotation index one from \RR2\RR^2 to S2.S^2. The domain of this harmonic map is identified with a neighborhood of the north pole in the domain S2S^2 via the exponential coordinates (α,θ).(\alpha,\theta). In these coordinates u(t,α)=Q(λ(t)α)+R(t,α),u(t,\alpha)=Q(\lambda(t)\alpha)+\mathcal{R}(t,\alpha), where Q(r)=2arctanr,Q(r)=2\arctan{r}, is the standard co-rotational harmonic map to the sphere, λ(t)=t1ν,\lambda(t)=t^{-1-\nu}, and R(t,α)\mathcal{R}(t,\alpha) is the error with local energy going to zero as t0.t\rightarrow 0. Blow up will occur at (t,α)=(0,0)(t,\alpha)=(0,0) due to energy concentration, and up to this point the solution will have regularity H1+ν.H^{1+\nu-}.

Keywords

Cite

@article{arxiv.1203.4722,
  title  = {Renormalization and blow up for wave maps from $S^2\times \RR$ to $S^2$},
  author = {Sohrab Shahshahani},
  journal= {arXiv preprint arXiv:1203.4722},
  year   = {2012}
}

Comments

Modified argument in section 4 (with the corresponding sections of the introduction). arXiv admin note: text overlap with arXiv:math/0610248 by other authors