@article {2007, title = {Solutions to the nonlinear Schroedinger equation carrying momentum along a curve. Part I: study of the limit set and approximate solutions}, number = {SISSA;51/2007/M}, year = {2007}, abstract = {We prove existence of a special class of solutions to the (elliptic) Nonlinear Schroeodinger Equation $- \\\\epsilon^2 \\\\Delta \\\\psi + V(x) \\\\psi = |\\\\psi|^{p-1} \\\\psi$, on a manifold or in the Euclidean space. Here V represents the potential, p an exponent greater than 1 and $\\\\epsilon$ a small parameter corresponding to the Planck constant. As $\\\\epsilon$ tends to zero (namely in the semiclassical limit) we prove existence of complex-valued solutions which concentrate along closed curves, and whose phase is highly oscillatory. Physically, these solutions carry quantum-mechanical momentum along the limit curves. In this first part we provide the characterization of the limit set, with natural stationarity and non-degeneracy conditions. We then construct an approximate solution up to order $\\\\epsilon^2$, showing that these conditions appear naturally in a Taylor expansion of the equation in powers of $\\\\epsilon$. Based on these, an existence result will be proved in the second part.}, url = {http://hdl.handle.net/1963/2112}, author = {Fethi Mahmoudi and Andrea Malchiodi and Marcelo Montenegro} } @article {2004, title = {Multidimensional boundary layers for a singularly perturbed Neumann problem}, journal = {Duke Math. J. 124 (2004) 105-143}, year = {2004}, publisher = {Duke University Press}, doi = {10.1215/S0012-7094-04-12414-5}, url = {http://hdl.handle.net/1963/2960}, author = {Andrea Malchiodi and Marcelo Montenegro} }