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We have investigated experimentally the magnetoresistance of strongly asymmetric double-wells. The structures were prepared by inserting a thin Al$_{0.3}$Ga$_{0.7}$As barrier into the GaAs buffer layer of a standard modulation-doped…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Yu. Krupko , L. Smrcka , P. Vasek , P. Svoboda , M. Cukr , L. Jansen

This paper aims to show that, in the limit of strong magnetic fields, the optimal domains for eigenvalues of magnetic Laplacians tend to exhibit symmetry. We establish several asymptotic bounds on magnetic eigenvalues to support this…

Spectral Theory · Mathematics 2025-09-11 Vladimir Lotoreichik , Léo Morin

We consider a particle bound to a two-dimensional plane and a double well potential, subject to a perpendicular uniform magnetic field . The energy difference between the lowest two eigenvalues--the eigenvalue splitting--is related to the…

Mathematical Physics · Physics 2022-01-25 Charles L. Fefferman , Jacob Shapiro , Michael I. Weinstein

Quantum tunneling between two potential wells in a magnetic field can be strongly increased when the potential barrier varies in the direction perpendicular to the line connecting the two wells and remains constant along this line. An…

Quantum Physics · Physics 2009-11-11 B. Ivlev

We continue our study of a magnetic Schr\"odinger operator on a two-dimensional compact Riemannian manifold in the case when the minimal value of the module of the magnetic field is strictly positive. We analyze the case when the magnetic…

Spectral Theory · Mathematics 2011-03-23 Bernard Helffer , Yuri A. Kordyukov

Inspired by a recent paper$^*$ by C. Fefferman, J. Shapiro and M. Weinstein, we investigate quantum tunneling for a Hamiltonian with a symmetric double well and a uniform magnetic field. In the simultaneous limit of strong magnetic field…

Mathematical Physics · Physics 2023-09-06 B. Helffer , A. Kachmar

We have investigated the magnetoresistance of strongly asymmetric double-well structures formed by a thin AlGaAs barrier grown far from the interface in the GaAs buffer of standard heterostructures. In magnetic fields oriented parallel to…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 P. Svoboda , Y. Krupko , L. Smrcka , M. Cukr , T. Jungwirth , L. Jansen

In this paper we derive formulae for the semiclassical tunneling in the presence of a constant magnetic field in 2 dimensions. The `wells' in the problem are identical discs with Neumann boundary conditions, so we study the magnetic Neumann…

Mathematical Physics · Physics 2024-11-20 Søren Fournais , Léo Morin

Experiments on a constant-density two-dimensional hole system in a GaAs quantum well reveal that the metallic behavior observed in the zero-magnetic-field temperature dependence of the resistivity depends on the symmetry of the confinement…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 S. J. Papadakis , E. P. De Poortere , H. C. Manoharan , M. Shayegan , R. Winkler

The weak-localization contribution \delta\sigma(B) to the conductivity of a tunnel-coupled double-layer electron system is evaluated and its behavior in weak magnetic fields B perpendicular or parallel to the layers is examined. In a…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 O. E. Raichev , P. Vasilopoulos

The magneto-electric properties of resonant tunneling double barrier structures using GaMnAs for the quantum well is investigated within a self-consistent Green's function approach and a tight-binding electronic structure model. The…

Mesoscale and Nanoscale Physics · Physics 2011-08-11 Christian Ertler , Walter Pötz

We investigate the combined influence of a magnetic field and a harmonic interparticle interaction on the thermodynamic properties of a finite number of spin polarized fermions in a confiment potential. This study is an extension using our…

Statistical Mechanics · Physics 2009-10-31 S. Foulon , F. Brosens , J. T. Devreese , L. F. Lemmens

We study perturbations of the discrete magnetic Laplacian associated to discrete analogs of funnels. We perturb the metric in a long-range way. We establish a propagation estimate and a Limiting Absorption Principle away from possible…

Mathematical Physics · Physics 2025-07-09 Nassim Athmouni , Marwa Ennaceur , Sylvain Golénia

We investigate how the lowest eigenvalue of a magnetic Laplacian depends on the geometry of a planar domain with a disk shaped hole, where the magnetic field is generated by a singular flux. Under Dirichlet boundary conditions on the inner…

Analysis of PDEs · Mathematics 2025-05-14 Mrityunjoy Ghosh , Ayman Kachmar

In this paper, we consider the semiclassical 2D magnetic Schr{\"o}dinger operator in the case where the magnetic field vanishes along a smooth closed curve. Assuming that this curve has an axis of symmetry, we prove that semi-classical…

Mathematical Physics · Physics 2022-12-09 Khaled Abou Alfa

In a two dimensional free electron gas (2DEG) subjected to a perpendicular spatially varying magnetic field, the classical paths of electrons are snake-like trajectories that weave along the line where the field crosses zero. But quantum…

Mesoscale and Nanoscale Physics · Physics 2018-05-09 Pervez Hoodbhoy

We study the tunneling of a spin polarized Fermi gas in a three-dimensional double well potential, focusing on the time dynamics starting from an initial state in which there is an imbalance in the number of particles in the two wells.…

Quantum Gases · Physics 2013-07-26 Tommaso Macri , Andrea Trombettoni

We focus on a dilute uniform suspension of magnetic nanoparticles in a nematic-filled micron-sized shallow well with tangent boundary conditions, as a paradigm system with two coupled order parameters. This system exhibits spontaneous…

Soft Condensed Matter · Physics 2020-03-04 Konark Bisht , Yiwei Wang , Apala Majumdar , Varsha Banerjee

An asymmetric double-well potential is considered, assuming that the minima of the wells are quadratic with a frequency $\omega$ and the difference of the minima is close to a multiple of $\hbar \omega$. A WKB wave function is constructed…

Quantum Physics · Physics 2011-04-13 Dae-Yup Song

The aim of the paper is to derive spectral estimates on the eigenvalue moments of the magnetic Dirichlet Laplacian defined on the two-dimensional disk with a radially symmetric magnetic field.

Spectral Theory · Mathematics 2016-08-17 Diana Barseghyan , Francoise Truc