7,622 research outputs found
Resonant tunneling of interacting electrons in a one-dimensional wire
We consider the conductance of a one-dimensional wire interrupted by a
double-barrier structure allowing for a resonant level. Using the
electron-electron interaction strength as a small parameter, we are able to
build a non-perturbative analytical theory of the conductance valid in a broad
region of temperatures and for a variety of the barrier parameters. We find
that the conductance may have a non-monotonic crossover dependence on
temperature, specific for a resonant tunneling in an interacting electron
system.Comment: 4 pages. 2 figure
Electromagnetic field induced suppression of transport through - junctions in graphene
We study quasi-particle transmission through an - junction in a
graphene irradiated by an electromagnetic field (EF). In the absence of EF the
electronic spectrum of undoped graphene is gapless, and one may expect the
perfect transmission of quasi-particles flowing perpendicular to the junction.
We demonstrate that the resonant interaction of propagating quasi-particles
with the component of EF parallel to the junction induces a
\textit{non-equilibrium dynamic gap} between electron and hole
bands in the quasi-particle spectrum of graphene. In this case the strongly
suppressed quasi-particle transmission is only possible due to interband
tunnelling. The effect may be used for controlling transport properties of
diverse structures in graphene, like, e.g., -- transistors, single
electron transistors, quantum dots, etc., by variation of the intensity and
frequency of the external radiation.Comment: 5 pages, 3 figure
Climate Modeling of a Potential ExoVenus
The planetary mass and radius sensitivity of exoplanet discovery capabilities
has reached into the terrestrial regime. The focus of such investigations is to
search within the Habitable Zone where a modern Earth-like atmosphere may be a
viable comparison. However, the detection bias of the transit and radial
velocity methods lies close to the host star where the received flux at the
planet may push the atmosphere into a runaway greenhouse state. One such
exoplanet discovery, Kepler-1649b, receives a similar flux from its star as
modern Venus does from the Sun, and so was categorized as a possible exoVenus.
Here we discuss the planetary parameters of Kepler-1649b with relation to Venus
to establish its potential as a Venus analog. We utilize the general
circulation model ROCKE-3D to simulate the evolution of the surface temperature
of Kepler-1649b under various assumptions, including relative atmospheric
abundances. We show that in all our simulations the atmospheric model rapidly
diverges from temperate surface conditions towards a runaway greenhouse with
rapidly escalating surface temperatures. We calculate transmission spectra for
the evolved atmosphere and discuss these spectra within the context of the
James Webb Space Telescope (JWST) Near-Infrared Spectrograph (NIRSpec)
capabilities. We thus demonstrate the detectability of the key atmospheric
signatures of possible runaway greenhouse transition states and outline the
future prospects of characterizing potential Venus analogs.Comment: 11 pages, 4 figures, 1 table, accepted for publication in the
Astrophysical Journal. The data from this paper are open source and are
available from the following data portals:
https://portal.nccs.nasa.gov/GISS_modelE/ROCKE-3D/Climate_Modeling_of_a_Potential_ExoVenus
https://archive.org/details/Climate_Modeling_of_a_Potential_ExoVenu
Is there a renormalization of the 1D conductance in Luttinger Liquid model?
Properties of 1D transport strongly depend on the proper choice of boundary
conditions. It has been frequently stated that the Luttinger Liquid (LL)
conductance is renormalized by the interaction as . To
contest this result I develop a model of 1D LL wire with the interaction
switching off at the infinities. Its solution shows that there is no
renormalization of the universal conductance while the electrons have a free
behavior in the source and drain reservoirs.Comment: 5 pages, RevTex 2.0, attempted repair of tex error
Analysis of heavy spin--3/2 baryon--heavy spin--1/2 baryon--light vector meson vertices in QCD
The heavy spin--3/2 baryon--heavy spin--1/2 baryon vertices with light vector
mesons are studied within the light cone QCD sum rules method. These vertices
are parametrized in terms of three coupling constants. These couplings are
calculated for all possible transitions. It is shown that correlation functions
for these transitions are described by only one invariant function for every
Lorenz structure. The obtained relations between the correlation functions of
the different transitions are structure independent while explicit expressions
of invariant functions depend on the Lorenz structure.Comment: 17 Pages, 6 Figures and 4 Table
Higgs Boson Decays to tau-pairs in the s-channel at a Muon Collider
We study the observability of the \tautau decay mode of a Higgs boson
produced in the -channel at a muon collider. We find that the spin
correlations of the \tautau in decays
are discriminative between the Higgs boson signal and the Standard Model
background. Observation of the predicted distinctive distribution can confirm
the spin-0 nature of the Higgs resonance. The relative coupling strength of the
Higgs boson to and can also be experimentally determined.Comment: to appear in PL
Dynamic coexistence of various configurations: clusters vs.nuclei
The presence of energy shells in metallic clusters and atomic nuclei leads to
a peculiar relation between the number of particles N and the structure, and
this leads to a strong correlation between the energy spectrum and N. An
analysis of experimental data leads to the conclusion that, in addition to the
static Jahn-Teller effect, the dynamic effect leading to the quantum
coexistence of different configurations (quantum oscillations) plays an
important role. Such suggested coexistence is an essential feature of clusters
as well as nuclei, both finite Fermi systems.Comment: 6 pages, 2 figure
Self-duality in quantum impurity problems
We establish the existence of an exact non-perturbative self-duality in a
variety of quantum impurity problems, including the Luttinger liquid or quantum
wire with impurity. The former is realized in the fractional quantum Hall
effect, where the duality interchanges electrons with Laughlin quasiparticles.
We discuss the mathematical structure underlying this property, which bears an
intriguing resemblance with the work of Seiberg and Witten on supersymmetric
non-abelian gauge theory.Comment: 4 page
Impurity Scattering in Luttinger Liquid with Electron-Phonon Coupling
We study the influence of electron-phonon coupling on electron transport
through a Luttinger liquid with an embedded weak scatterer or weak link. We
derive the renormalization group (RG) equations which indicate that the
directions of RG flows can change upon varying either the relative strength of
the electron-electron and electron-phonon coupling or the ratio of Fermi to
sound velocities. This results in the rich phase diagram with up to three fixed
points: an unstable one with a finite value of conductance and two stable ones,
corresponding to an ideal metal or insulator.Comment: 4 pages, 2 figure
The Fractional Quantum Hall effect in an array of quantum wires
We demonstrate the emergence of the quantum Hall (QH) hierarchy in a 2D model
of coupled quantum wires in a perpendicular magnetic field. At commensurate
values of the magnetic field, the system can develop instabilities to
appropriate inter-wire electron hopping processes that drive the system into a
variety of QH states. Some of the QH states are not included in the
Haldane-Halperin hierarchy. In addition, we find operators allowed at any field
that lead to novel crystals of Laughlin quasiparticles. We demonstrate that any
QH state is the groundstate of a Hamiltonian that we explicitly construct.Comment: Revtex, 4 pages, 2 figure
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