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Related papers: Eigenvalue estimates for bilayer graphene

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We consider eigenvalue sums of Schr\"odinger operators $-\Delta+V$ on $L^2(\R^d)$ with complex radial potentials $V\in L^q(\R^d)$, $q<d$. We prove quantitative bounds on the distribution of the eigenvlaues in terms of the $L^q$ norm of $V$.…

Spectral Theory · Mathematics 2024-09-06 Jean-Claude Cuenin , Solomon Keedle-Isack

We study the problem of minimizing or maximizing the fundamental spectral gap of Schr\"odinger operators on metric graphs with either a convex potential or a ``single-well'' potential on an appropriate specified subset. (In the case of…

Spectral Theory · Mathematics 2024-01-10 Mohammed Ahrami , Zakaria El Allali , Evans M Harrell , James B. Kennedy

We study the optimal estimation of probability matrices of random graph models generated from graphons. This problem has been extensively studied in the case of step-graphons and H\"older smooth graphons. In this work, we characterize the…

Statistics Theory · Mathematics 2024-10-03 Yuchen Chen , Jing Lei

Twisted bilayer graphene exhibits isolated, relatively flat electronic bands near charge neutrality when the interlayer rotation is tuned to specific magic angles. These small misalignments, typically below 1.1{\deg}, result in long-period…

Mesoscale and Nanoscale Physics · Physics 2026-03-26 Antonio Palamara , Michele Pisarra , Antonello Sindona

Given a graph $G$, let $\lambda_3$ denote the third largest eigenvalue of its adjacency matrix. In this paper, we prove various results towards the conjecture that $\lambda_3(G) \le \frac{|V(G)|}{3}$, motivated by a question of Nikiforov.…

Combinatorics · Mathematics 2026-02-10 Giacomo Leonida , Sida Li

In this paper, we investigate the eigenvalue problem for a non-local dispersal operator defined on a bounded spatial domain with Neumann-type boundary conditions. Unlike the classical Laplacian, the non-local operator lacks compactness,…

Spectral Theory · Mathematics 2026-05-26 Maciej Tadej

We consider the Schr\"odinger operator on a combinatorial graph consisting of a finite graph and a finite number of discrete half-lines, all jointed together, and compute an asymptotic expansion of its resolvent around the threshold $0$.…

Spectral Theory · Mathematics 2018-04-17 Kenichi Ito , Arne Jensen

Using a correspondence between the spectrum of the damped wave equation and non-self-adjoint Schroedinger operators, we derive various bounds on complex eigenvalues of the former. In particular, we establish a sharp result that the…

Spectral Theory · Mathematics 2022-08-22 David Krejcirik , Tereza Kurimaiova

Let $L$ be a non-negative self-adjoint operator on $L^2(X)$. Assume that operator $L$ generates the analytic semigroup $\{e^{-tL}\}_{t>0}$ whose kernels satisfy the standard Gaussian upper bounds. This paper investigates the sharp weighted…

Functional Analysis · Mathematics 2011-09-09 The Anh Bui

Given an elliptic diffusion operator $L$ defined on a compact and connected manifold (possibly with a convex boundary in a suitable sense) with an $L$-invariant measure $m$, we introduce the non-linear $p-$operator $L_p$, generalizing the…

Analysis of PDEs · Mathematics 2019-07-26 Thomas Koerber

Let $(M,g)$ be an $n$-dimensional compact boudaryless Riemannian manifold with nonpositive sectional curvature, then our conclusion is that we can give improved estimates for the $L^p$ norms of the restrictions of eigenfunctions to smooth…

Analysis of PDEs · Mathematics 2012-10-31 Xuehua Chen

We calculate the form of quasiparticle interference patterns in bilayer graphene within a low-energy description, taking into account perturbatively the trigonal warping terms. We introduce four different types of impurities localized on…

Bilayer graphene has the very interesting property of an energy gap tunable with the vertical electric field. We propose an analytical model for a bilayer-graphene field-effect transistor, suitable for exploring the design parameter space…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Martina Cheli , Gianluca Fiori , Giuseppe Iannaccone

In this work we study the homogenization problem for (nonlinear) eigenvalues of quasilinear elliptic operators. We prove convergence of the first and second eigenvalues and, in the case where the operator is independent of $\varepsilon$,…

Analysis of PDEs · Mathematics 2012-11-20 Julian Fernandez Bonder , Juan P. Pinasco , Ariel M. Salort

We study eigenvalues of the Dirac operator with canonical form \begin{equation} L_{p,q} \begin{pmatrix} u \\ v \end{pmatrix}= \begin{pmatrix} 0 & -1 \\ 1 & 0 \end{pmatrix}\frac{d}{dt} \begin{pmatrix} u \\ v \end{pmatrix}+\begin{pmatrix} -p…

Spectral Theory · Mathematics 2023-12-27 Vishwam Khapre , Kang Lyu , Andrew Yu

Let $(M,g)$ be a two-dimensional compact boundaryless Riemannian manifold with nonpostive curvature, then we shall give improved estimates for the $L^2$-norms of the restrictions of eigenfunctions to unit-length geodesics, compared to the…

Analysis of PDEs · Mathematics 2011-09-12 Christopher D. Sogge , Steve Zelditch

We study the effect of spatial modulations in the interlayer hopping of graphene bilayers, such as those that arise upon shearing or twisting. We show that their single-particle physics, characterized by charge accumulation and recurrent…

Mesoscale and Nanoscale Physics · Physics 2012-05-24 Pablo San-Jose , Jose Gonzalez , Francisco Guinea

The celebrated Cwikel-Lieb_Rozenblum inequality gives an upper estimate for the number of negative eigenvalues of Schroedinger operators in dimension three and higher. The situation is much more difficult in the two dimensional case. There…

Spectral Theory · Mathematics 2016-09-27 Martin Karuhanga

We study the right eigenvalue equation for quaternionic and complex linear matrix operators defined in n-dimensional quaternionic vector spaces. For quaternionic linear operators the eigenvalue spectrum consists of n complex values. For…

Mathematical Physics · Physics 2009-10-31 Stefano De Leo , Giuseppe Scolarici

We show that in AB stacked bilayer graphene low energy excitations around the semimetallic points are described by massless, four dimensional Dirac fermions. There is an effective reconstruction of the 4 dimensional spacetime, including in…

Mesoscale and Nanoscale Physics · Physics 2017-06-28 M. Cariglia , R. Giambò , A. Perali