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Related papers: Non-concavity of Robin eigenfunctions

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We study spectral behavior of the complex Laplacian on forms with values in the $k^{\text{th}}$ tensor power of a holomorphic line bundle over a smoothly bounded domain with degenerated boundary in a complex manifold. In particular, we…

Complex Variables · Mathematics 2007-12-10 Siqi Fu , Howard Jacobowitz

We establish rigorous quantitative inequalities for the first eigenvalue of the generalized $p$-Robin problem, for both the classical diffusion absorption case, where the Robin boundary parameter $\alpha$ is positive, and the…

Analysis of PDEs · Mathematics 2025-04-04 Lukas Bundrock , Tiziana Giorgi , Robert Smits

We consider a general second order linear elliptic equation in a finely perforated domain. The shapes of cavities and their distribution in the domain are arbitrary and non-periodic; they are supposed to satisfy minimal natural geometric…

Analysis of PDEs · Mathematics 2022-08-24 D. I. Borisov , J. Kriz

Previous works provided several counterexamples to monotonicity of the lowest eigenvalue for the magnetic Laplacian in the two-dimensional case. However, the three-dimensional case is less studied. We use the results obtained by Helffer,…

Spectral Theory · Mathematics 2022-09-21 Germán Miranda

We prove that the Cauchy data of Dirichlet or Neumann $\Delta$- eigenfunctions of Riemannian manifolds with concave (diffractive) boundary can only achieve maximal sup norm bounds if there exists a self-focal point on the boundary, i.e. a…

Analysis of PDEs · Mathematics 2017-09-25 C. D. Sogge , S. Zelditch

The asymptotic behavior of the first eigenvalues of magnetic Laplacian operators with large magnetic fields and Neumann realization in smooth three-dimensional domains is characterized by model problems inside the domain or on its boundary.…

Spectral Theory · Mathematics 2017-11-23 Virginie Bonnaillie-Noël , Monique Dauge , Nicolas Popoff

In this paper, we prove that the Extended Courant Property fails to be true for certain smooth, strictly convex domains with Neumann boundary condition: there exists a linear combination of a second and a first Neumann eigenfunctions, with…

Spectral Theory · Mathematics 2022-01-04 Pierre Bérard , Bernard Helffer

Characterizations of eigenvalues and eigenfunctions of the Laplacian on a product domain are obtained. When zero Dirichlet, Robin or Neumann boundary conditions are specified on each factor, then the eigenfunctions on the product domain are…

Analysis of PDEs · Mathematics 2015-11-06 Giles Auchmuty , M. A. Rivas

We consider the eigenvalue problem for the Laplacian with mixed Dirichlet and Neumann boundary conditions. For a certain class of bounded, simply connected planar domains we prove monotonicity properties of the first eigenfunction. As a…

Spectral Theory · Mathematics 2025-02-06 Nausica Aldeghi , Jonathan Rohleder

We consider the magnetic Robin Laplacian with a negative boundary parameter. Among a certain class of domains, we prove that the disk maximizes the ground state energy under the fixed perimeter constraint provided that the magnetic field is…

Spectral Theory · Mathematics 2022-05-03 Ayman Kachmar , Vladimir Lotoreichik

In this paper, we prove that the first (positive) Dirichlet eigenvalue of the Ornstein-Uhlenbeck operator \[ L(u)=\Delta u-(\nabla u,x), \] is strongly log-concave if the domain is bounded and convex, which improves the conclusion in [6].…

Analysis of PDEs · Mathematics 2025-07-02 Lei Qin

The considered Robin problem can formally be seen as a small perturbation of a Dirichlet problem. However, due to the sign of the impedance value, its associated eigenvalues converge point-wise to $-\infty$ as the perturbation goes to zero.…

Analysis of PDEs · Mathematics 2013-08-07 Fioralba Cakoni , Nicolas Chaulet , Houssem Haddar

In [SWW16, HW17] it is shown that the difference of the first two eigenvalues of the Laplacian with Dirichlet boundary condition on convex domain with diameter $D$ of sphere $\mathbb S^n$ is $\geq 3 \frac{\pi^2}{D^2}$ when $n \geq 3$. We…

Differential Geometry · Mathematics 2018-03-06 Xianzhe Dai , Shoo Seto , Guofang Wei

In this paper, we obtain optimal upper bounds for all the Neumann eigenvalues in two situations (that are closely related). First we consider a one-dimensional Sturm-Liouville eigenvalue problem where the density is a function $h(x)$ whose…

Analysis of PDEs · Mathematics 2022-12-01 Antoine Henrot , Marco Michetti

We write down a Robin boundary term for general relativity. The construction relies on the Neumann result of arXiv:1605.01603 in an essential way. This is unlike in mechanics and (polynomial) field theory, where two formulations of the…

General Relativity and Quantum Cosmology · Physics 2017-09-13 Chethan Krishnan , Shubham Maheshwari , P. N. Bala Subramanian

The third eigenvalue of the Robin Laplacian on a simply-connected planar domain of given area is bounded above by the corresponding eigenvalue of a disjoint union of two equal disks, for Robin parameters in $[-4\pi,4\pi]$. This sharp…

Spectral Theory · Mathematics 2025-01-28 Hanna N. Kim , Richard S. Laugesen

We determine accurate asymptotics for the low-lying eigenvalues of the Robin Laplacian when the Robin parameter goes to $-\infty$. The two first terms in the expansion have been obtained by K. Pankrashkin in the $2D$-case and by K.…

Spectral Theory · Mathematics 2015-04-30 Bernard Helffer , Ayman Kachmar

For a bounded Lipschitz domain $\Sigma$ in a Riemannian surface $M$ satisfying certain curvature condition, we prove that $$\mu_{3-\beta_1} \leq \lambda_{1},$$ where $\mu_k$ ($\lambda_k$ resp.) is the $k$-th Neumann (Dirichlet resp.)…

Differential Geometry · Mathematics 2025-06-04 Bobo Hua , Florentin Münch , Haohang Zhang

For a linear, strictly elliptic second order differential operator in divergence form with bounded, measurable coefficients on a Lipschitz domain $\Omega$ we show that solutions of the corresponding elliptic problem with Robin and thus in…

Analysis of PDEs · Mathematics 2011-06-08 Robin Nittka

We consider the Robin Laplacian in the domains $\Omega$ and $\Omega^\varepsilon$, $\varepsilon >0$, with sharp and blunted cusps, respectively. Assuming that the Robin coefficient $a$ is large enough, the spectrum of the problem in $\Omega$…

Analysis of PDEs · Mathematics 2018-10-01 Sergei A. Nazarov , Nicolas Popoff , Jari Taskinen