The levinson theorem

ZQ Ma - Journal of Physics A: Mathematical and General, 2006 - iopscience.iop.org
The Levinson theorem is a fundamental theorem in quantum scattering theory, which shows
the relation between the number of bound states and the phase shift at zero momentum for …

Zero-energy states in graphene quantum dots and rings

CA Downing, DA Stone, ME Portnoi - Physical Review B—Condensed Matter …, 2011 - APS
We present exact analytical zero-energy solutions for a class of smooth-decaying potentials,
showing that the full confinement of charge carriers in electrostatic potentials in graphene …

Bielectron vortices in two-dimensional Dirac semimetals

CA Downing, ME Portnoi - Nature communications, 2017 - nature.com
Searching for new states of matter and unusual quasi-particles in emerging materials and
especially low-dimensional systems is one of the major trends in contemporary condensed …

Zero‐energy vortices in Dirac materials

CA Downing, ME Portnoi - physica status solidi (b), 2019 - Wiley Online Library
In this brief review, the problem of electrostatic confinement of massless Dirac particles is
surveyed via a number of exactly solvable one‐and two‐body models. By considering …

Magnetic quantum dots and rings in two dimensions

CA Downing, ME Portnoi - Physical Review B, 2016 - APS
We consider the motion of electrons confined to a two-dimensional plane with an externally
applied perpendicular inhomogeneous magnetic field, both with and without a Coulomb …

Searching for confined modes in graphene channels: The variable phase method

DA Stone, CA Downing, ME Portnoi - Physical Review B—Condensed Matter …, 2012 - APS
Using the variable phase method, we reformulate the Dirac equation governing the charge
carriers in graphene into a nonlinear first-order differential equation from which we can treat …

[HTML][HTML] The 2D Debye length: An analytical study of weak charge screening in 2D semiconductors

AR Bechhofer, A Ueda, A Nipane… - Journal of Applied …, 2021 - pubs.aip.org
Simple perturbations (such as a line charge or a sheet charge) in 2D semiconducting
materials create difficult solutions to the Poisson equation due to the non-uniform out-of …

Relativistic Levinson theorem in two dimensions

SH Dong, XW Hou, ZQ Ma - Physical Review A, 1998 - APS
In the light of the generalized Sturm-Liouville theorem, the Levinson theorem for the Dirac
equation in two dimensions is established as a relation between the total number nj of the …

Optimal traps in graphene

CA Downing, AR Pearce, RJ Churchill, ME Portnoi - Physical Review B, 2015 - APS
We transform the two-dimensional Dirac-Weyl equation, which governs the charge carriers
in graphene, into a nonlinear first-order differential equation for scattering phase shift, using …

Multiple polaron quasiparticles with dipolar fermions in a bilayer geometry

A Tiene, AT Bracho, MM Parish, J Levinsen… - Physical Review A, 2024 - APS
We study the Fermi polaron problem with dipolar fermions in a bilayer geometry, where a
single dipolar particle in one layer interacts with a Fermi sea of dipolar fermions in the other …