Browsing Analysis of Partial Differential Equations (APDE) by Title
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SelfAdjoint Extensions for the Dirac Operator with CoulombType Spherically Symmetric Potentials
(Letters in Mathematical Physics, 2018)We describe the selfadjoint realizations of the operator $H:=i\alpha\cdot \nabla + m\beta + \mathbb V(x)$, for $m\in\mathbb R $, and $\mathbb V(x)= x^{1} ( \nu \mathbb{I}_4 +\mu \beta i \lambda \alpha\cdot{x}/{x}\,\beta)$, ... 
Sharp bounds for the ratio of modified Bessel functions
(Mediterranean Journal of Mathematics, 20170621)Let $I_{\nu }\left( x\right) $ be the modified Bessel functions of the first kind of order $\nu $, and $S_{p,\nu }\left( x\right) =W_{\nu }\left( x\right) ^{2}2pW_{\nu }\left( x\right) x^{2}$ with $W_{\nu }\left( x\right) ... 
Sharp exponential localization for eigenfunctions of the Dirac Operator
(2018)We determine the fastest possible rate of exponential decay at infinity for eigenfunctions of the Dirac operator $\mathcal D_n + \mathbb V$, being $\mathcal D_n$ the massless Dirac operator in dimensions $n=2,3$ and ... 
Sharp weighted estimates involving one supremum
(Comptes Rendus Mathematique, 201707)In this note, we study the sharp weighted estimate involving one supremum. In particular, we give a positive answer to an open question raised by Lerner and Moen. We also extend the result to rough homogeneous singular ... 
Shear flow dynamics in the BerisEdwards model of nematic liquid crystals
(Proceedings of the Royal Society AMathematical, Physical and Engineering Sciences, 20180214)We consider the BerisEdwards model describing nematic liquid crystal dynamics and restrict to a shear flow and spatially homogeneous situation. We analyze the dynamics focusing on the effect of the flow. We show that in ... 
Shell interactions for Dirac operators: On the point spectrum and the confinement
(SIAM Journal on Mathematical Analysis, 20151231)Spectral properties and the confinement phenomenon for the coupling $H + V$ are studied, where $H =i\alpha \cdot \nabla + m\beta$ is the free Dirac operator in $\mathbb{R}^3$ and $V$ is a measurevalued potential. The ... 
Singular Perturbation of the Dirac Hamiltonian
(20171215)This thesis is devoted to the study of the Dirac Hamiltonian perturbed by deltatype potentials and Coulombtype potentials. We analysed the deltashell interaction on bounded and smooth domains and its approximation by ... 
Singularity formation for the 1D cubic NLS and the Schrödinger map on $\mathbb{S}^2$
(20170202)In this note we consider the 1D cubic Schrödinger equation with data given as small perturbations of a Dirac$\delta$ function and some other related equations. We first recall that although the problem for this type of ... 
Some remark on the existence of infinitely many nonphysical solutions to the incompressible NavierStokes equations
(Journal of Mathematical Analysis and Applications, 201810)We prove that there exist infinitely many distributional solutions with infinite kinetic energy to both the incompressible NavierStokes equations in $ \mathbb{R}^2 $ and Burgers equation in $\mathbb{R} $ with vanishing ... 
Some remarks on the $L^p$ regularity of second derivatives of solutions to nondivergence elliptic equations and the Dini condition
(Rendiconti Lincei  Matematica e Applicazioni, 20170530)In this note we prove an endpoint regularity result on the $L^P$ integrability of the second derivatives of solutions to nondivergence form uniformly elliptic equations whose second derivatives are a priori only known ... 
Sparse bounds for maximal rough singular integrals via the Fourier transform
(Annales de l'institut Fourier, 20190312)We prove a quantified sparse bound for the maximal truncations of convolutiontype singular integrals with suitable Fourier decay of the kernel. Our result extends the sparse domination principle by CondeAlonso, Culiuc, ... 
Sparse bounds for pseudodifferential operators
(Journal d'Analyse Mathématique, 2018)We prove sparse bounds for pseudodifferential operators associated to H\"ormander symbol classes. Our sparse bounds are sharp up to the endpoint and rely on a single scale analysis. As a consequence, we deduce a range of ... 
Sparse domination theorem for multilinear singular integral operators with $L^{r}$Hörmander condition
(Michigan Mathematical Journal, 20170401)In this note, we show that if $T$ is a multilinear singular integral operator associated with a kernel satisfies the socalled multilinear $L^{r}$Hörmander condition, then $T$ can be dominated by multilinear sparse operators. 
Spectral asymptotics for $\delta$interactions on sharp cones
(Journal of Mathematical Analysis and Applications, 2017)We investigate the spectrum of threedimensional Schr\"odinger operators with $\delta$interactions of constant strength supported on circular cones. As shown in earlier works, such operators have infinitely many eigenvalues ... 
Spectral asymptotics of the Dirichlet Laplacian in a conical layer
(Communications on Pure and Applied Analysis, 20150501)The spectrum of the Dirichlet Laplacian on conical layers is analysed through two aspects: the infiniteness of the discrete eigenvalues and their expansions in the small aperture limit. On the one hand, we prove that, for ... 
Spectral stability of Schrödinger operators with subordinated complex potentials
(Journal of Spectral Theory, 20180628)We prove that the spectrum of Schroedinger operators in three dimensions is purely continuous and coincides with the nonnegative semiaxis for all potentials satisfying a formsubordinate smallness condition. By developing ... 
Spectral Transitions for AharonovBohm Laplacians on Conical Layers
(20160711)We consider the Laplace operator in a tubular neighbourhood of a conical surface of revolution, subject to an AharonovBohm magnetic field supported on the axis of symmetry and Dirichlet boundary conditions on the boundary ... 
Spherevalued harmonic maps with surface energy and the K13 problem
(Advances in the Calculus of Variations, 201711)We consider an energy functional motivated by the celebrated K13 problem in the OseenFrank theory of nematic liquid crystals. It is defined for spherevalued functions and appears as the usual Dirichlet energy with an ... 
A strategy for selfadjointness of Dirac operators: Applications to the MIT bag model and deltashell interactions
(20161221)We develop an approach to prove selfadjointness of Dirac operators with boundary or transmission conditions at a $C^2$compact surface without boundary. To do so we are lead to study the layer potential induced by the ... 
The dynamics of vortex filaments with corners
(Communications on Pure and Applied Analysis (CPAA), 20150701)This paper focuses on surveying some recent results obtained by the author together with V. Banica on the evolution of a vortex filament with one corner according to the socalled binormal flow. The case of a regular polygon ...