Results 21 to 30 of about 869 (34)

An estimate for the number of bound states of the Schrödinger operator in two dimensions [PDF]

open access: yes, 2004
For the Schrödinger operator -Δ + V on R^2 be the number of bound states. One obtains the following estimate: N(V) ≤ 1 + ∫_(R^2)∫_(R^2)|V(x)|V(y)|C_(1)ln|x-y|+C_2|^2 dx dy where C_1 = -1/2π and C_2 = (ln2-γ)/2π (γ is the Euler constant).
Stoiciu, Mihai
core  

Separation of Coupled Systems of Schrodinger Equations by Darboux transformations

open access: yes, 2011
Darboux transformations in one independent variable have found numerous applications in various field of mathematics and physics. In this paper we show that the extension of these transformations to two dimensions can be used to decouple systems of ...
Magri F.   +3 more
core   +1 more source

Smoothing estimates for variable coefficients Schroedinger equation with electromagnetic potentials

open access: yes, 2012
In this paper we develop the classical multiplier technique to prove a virial identity and smoothing estimates (in a perturbative setting) for the electromagnetic variable coefficients Schroedinger equation.Comment: 15 ...
Cacciafesta, Federico
core   +1 more source

New bounds on the Lieb-Thirring constants

open access: yes, 1999
Improved estimates on the constants $L_{\gamma,d}$, for $1 ...
Hundertmark, D., Laptev, A., Weidl, T.
core   +1 more source

A recipe for making materials with negative refraction in acoustics

open access: yes, 2007
A recipe is given for making materials with negative refraction in acoustics, i.e., materials in which the group velocity is directed opposite to the phase velocity.
A.G. Ramm, Agranovich, Ramm, Ramm, Ramm
core   +4 more sources

Semiclassical analysis for a Schr\"odinger operator with a U(2) artificial gauge: the periodic case [PDF]

open access: yes, 2014
We consider a Schr\"odinger operator with a Hermitian 2x2 matrix-valued potential which is lattice periodic and can be diagonalized smoothly on the whole $R^n.$ In the case of potential taking its minimum only on the lattice, we prove that the well-known
Morame, Abderemane, Truc, Francoise
core  

Multiple Aharonov--Bohm eigenvalues: the case of the first eigenvalue on the disk

open access: yes, 2018
It is known that the first eigenvalue for Aharonov--Bohm operators with half-integer circulation in the unit disk is double if the potential's pole is located at the origin. We prove that in fact it is simple as the pole $a\neq 0$
Abatangelo, Laura
core   +1 more source

A counterexample to an endpoint bilinear Strichartz inequality

open access: yes, 2006
The endpoint Strichartz estimate $\| e^{it\Delta} f \|_{L^2_t L^\infty_x(\R \times \R^2)} \lesssim \|f\|_{L^2_x(\R^2)}$ is known to be false by the work of Montgomery-Smith, despite being only ``logarithmically far'' from being true in some sense.
Tao, Terence
core   +1 more source

An Agmon-Allegretto-Piepenbrink principle for Schrödinger operators. [PDF]

open access: yesRev R Acad Cienc Exactas Fis Nat A Mat, 2022
Buccheri S, Orsina L, Ponce AC.
europepmc   +1 more source

On a Kirchhoff type problems with potential well and indefinite potential

open access: yes, 2015
In this paper, we study the following Kirchhoff type problem:% $$ \left\{\aligned&-\bigg(\alpha\int_{\bbr^3}|\nabla u|^2dx+1\bigg)\Delta u+(\lambda a(x)+a_0)u=|u|^{p-2}u&\text{ in }\bbr^3,\\% &u\in\h,\endaligned\right.\eqno{(\mathcal{P}_{\alpha,\lambda})}
Huang, Yisheng, Liu, Zeng, Wu, Yuanze
core   +1 more source

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