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Manuel del Pino

Publications and source records attributed to Manuel del Pino.

65 records · Page 4Linked to original sources
arXiv2013

Concentrating standing waves for the fractional nonlinear Schrödinger equation

We consider the semilinear equation $$ ε^{2s} (-Δ)^s u + V(x)u - u^p = 0, \quad u>0, \quad u\in H^{2s}(\R^N) $$ where $0 0$, and $ε>0$ is a small number. Letting $w_λ$ be the radial ground state of $(-Δ)^s w_λ+ λw_λ- w_λ^p=0$ in $H^{2s}(\R^N)$, we build solutions of the form $$ u_ε(x) \sim \sum_{i=1}^k w_{λ_i} ((x-ξ_i^ε)/ε),$$ where $λ_i = V(ξ_i^ε)$ and the $ξ_i^ε$ approach suitable critical points of $V$. Via a Lyapunov Schmidt variational reduction, we recover various existence results already known for the case $s=1$. In particular such a solution exists around $k$ nondegenerate critical points of $V$. For $s=1$ this corresponds to the classical results by Floer-Weinstein and Oh.

math.AP↗
arXiv2013

Nonlocal Minimal Lawson Cones

We prove the existence of the analog of Lawson's minimal cones for a notion of nonlocal minimal surface introduced by Caffarelli, Roquejoffre and Savin, and establish their stability/instability in low dimensions. In particular we find that there are nonlocal stable minimal cones in dimension 7, in contrast with the case of classical minimal surfaces.

math.AP↗
arXiv2012

Type II ancient compact solutions to the Yamabe flow

We construct new type II ancient compact solutions to the Yamabe flow. Our solutions are rotationally symmetric and converge, as $t \to -\infty$, to a tower of two spheres. Their curvature operator changes sign. We allow two time-dependent parameters in our ansatz. We use perturbation theory, via fixed point arguments, based on sharp estimates on ancient solutions of the approximated linear equation and careful estimation of the error terms which allow us to make the right choice of parameters. Our technique may be viewed as a parabolic analogue of gluing two exact solutions to the rescaled equation, that is the spheres, with narrow cylindrical necks to obtain a new ancient solution to the Yamabe flow. The techniques in this article may be generalized to the gluing of $n$ spheres.

math.DG↗
arXiv2010

Interface Foliation Near Minimal Submanifolds in Riemannian Manifolds with Positive Ricci Curvature

Let $(\MM ,{\tilde g})$ be an $N$-dimensional smooth compact Riemannian manifold. We consider the singularly perturbed Allen-Cahn equation $$ ε^2Δ_{ {\tilde g}} {u}\,+\, (1 - {u}^2)u \,=\,0\quad \mbox{in } \MM, $$ where $ε$ is a small parameter. Let $\KK\subset \MM$ be an $(N-1)$-dimensional smooth minimal submanifold that separates $\MM$ into two disjoint components. Assume that $\KK$ is non-degenerate in the sense that it does not support non-trivial Jacobi fields, and that $|A_{\KK}|^2+\mbox{Ric}_{\tilde g}(ν_{\KK}, ν_{\KK})$ is positive along $\KK$. Then for each integer $m\geq 2$, we establish the existence of a sequence $ε= ε_j\to 0$, and solutions $u_ε$ with $m$-transition layers near $\KK$, with mutual distance $O(ε|\ln ε|)$.

math.AP↗
arXiv2009

On De Giorgi Conjecture in Dimension $N \geq 9$

A celebrated conjecture due to De Giorgi states that any bounded solution of the equation $Δu + (1-u^2) u = 0 \hbox{in} \R^N $ with $\pp_{y_N}u >0$ must be such that its level sets $\{u=\la\}$ are all hyperplanes, {\em \bf at least} for dimension $N\le 8$. A counterexample for $N\ge 9$ has long been believed to exist. Based on a minimal graph $Γ$ which is not a hyperplane, found by Bombieri, De Giorgi and Giusti in $\R^N$, $N\ge 9$, we prove that for any small $α>0$ there is a bounded solution $u_α(y)$ with $\pp_{y_N}u_α>0$, which resembles $ \tanh (\frac t{\sqrt{2}}) $, where $t=t(y)$ denotes a choice of signed distance to the blown-up minimal graph $Γ_α:= α^{-1}Γ$. This solution constitutes a counterexample to De Giorgi conjecture for $N\ge 9$.

math.AP↗
arXiv2009

Entire Solutions of the Allen-Cahn equation and Complete Embedded Minimal Surfaces of Finite Total Curvature in $\R^3$

We consider minimal surfaces $M$ which are complete, embedded and have finite total curvature in $\R^3$, and bounded, entire solutions with finite Morse index of the Allen-Cahn equation $Δu + f(u) = 0 \hbox{in} \R^3 $. Here $f=-W'$ with $W$ bistable and balanced, for instance $W(u) =\frac 14 (1-u^2)^2$. We assume that $M$ has $m\ge 2$ ends, and additionally that $M$ is non-degenerate, in the sense that its bounded Jacobi fields are all originated from rigid motions (this is known for instance for a Catenoid and for the Costa-Hoffman-Meeks surface of any genus). We prove that for any small $α>0$, the Allen-Cahn equation has a family of bounded solutions depending on $m-1$ parameters distinct from rigid motions, whose level sets are embedded surfaces lying close to the blown-up surface $M_α:= α^{-1} M$, with ends possibly diverging logarithmically from $M_\A$. We prove that these solutions are $L^\infty$-{\em non-degenerate} up to rigid motions, and find that their Morse index coincides with the index of the minimal surface. Our construction suggests parallels of De Giorgi conjecture for general bounded solutions of finite Morse index.

math.AP↗
arXiv2007

The Toda system and multiple-end solutions of autonomous planar elliptic problems

We construct a new class of positive solutions for a classical semilinear elliptic problem in the plane which arise for instance as the standing-wave problem for the standard nonlinear Schrödinger equation or in nonlinear models in Turing's theory biological theory of pattern formation such as the Gray-Scott or Gierer-Meinhardt systems. The solutions we construct have the property that their energy over a ball of radius R grows linearly with R as R tends to infinity. These solutions are strongly related to the solutions of a Toda system.

math.AP↗
arXiv2007

Boundary singularities for weak solutions of semilinear elliptic problems

We construct positive weak solutions of a class of semilinear elliptic equation which vanish in suitable trace sense on the boundary of a given smooth bounded N-dimensional domain, but which are singular at prescribed isolated points of the boundary. Similar constructions are carried out for solutions which are singular on any given embedded submanifold of the boundary.

math.AP↗
arXiv2006

The two-dimensional Lazer-McKenna conjecture for an exponential nonlinearity

We consider the problem of Ambrosetti-Prodi type \begin{equation}\label{0}\quad\begin{cases} Δu + e^u = sϕ_1 + h(x) &\hbox{in} Ω, u=0 & \hbox{on} \partial Ω, \end{cases} \nonumber \end{equation} where $Ω$ is a bounded, smooth domain in $\R^2$, $ϕ_1$ is a positive first eigenfunction of the Laplacian under Dirichlet boundary conditions and $h\in\mathcal{C}^{0,α}(\barΩ)$. We prove that given $k\ge 1$ this problem has at least $k$ solutions for all sufficiently large $s>0$, which answers affirmatively a conjecture by Lazer and McKenna \cite{LM1} for this case. The solutions found exhibit multiple concentration behavior around maxima of $ϕ_1$ as $s\to +\infty$.

math.AP↗