8,851 research outputs found
Existence and Vanishing of the Breathing Mode in Strongly Correlated Finite Systems
One of the fundamental eigenmodes of finite interacting systems is the mode
of {\em uniform radial expansion and contraction} -- the ``breathing'' mode
(BM). Here we show in a general way that this mode exists only under special
conditions: i) for harmonically trapped systems with interaction potentials of
the form or , or ii) for
some systems with special symmetry such as single shell systems forming
platonic bodies. Deviations from the BM are demonstrated for two examples:
clusters interacting with a Lennard-Jones potential and parabolically trapped
systems with Yukawa repulsion. We also show that vanishing of the BM leads to
the occurence of multiple monopole oscillations which is of importance for
experiments
Interaction between dust grains near a conducting wall
The effect of the conducting electrode on the interaction of dust grains in a
an ion flow is discussed. It is shown that two grains levitating above the
electrode at the same height may attract one another. This results in the
instability of a dust layer in a plasma sheath.Comment: 9 pages. 3 figures. Submitted to Plasma Physics Report
Self consistent theory of unipolar charge-carrier injection in metal/insulator/metal systems
A consistent device model to describe current-voltage characteristics of
metal/insulator/metal systems is developed. In this model the insulator and the
metal electrodes are described within the same theoretical framework by using
density of states distributions. This approach leads to differential equations
for the electric field which have to be solved in a self consistent manner by
considering the continuity of the electric displacement and the electrochemical
potential in the complete system. The model is capable of describing the
current-voltage characteristics of the metal/insulator/metal system in forward
and reverse bias for arbitrary values of the metal/ insulator injection
barriers. In the case of high injection barriers, approximations are provided
offering a tool for comparison with experiments. Numerical calculations are
performed exemplary using a simplified model of an organic semiconductor.Comment: 21 pages, 8 figure
Self-consistent model of unipolar transport in organic semiconductor diodes: accounting for a realistic density-of-states distribution
A self-consistent, mean-field model of charge-carrier injection and unipolar
transport in an organic semiconductor diode is developed utilizing the
effective transport energy concept and taking into account a realistic
density-of-states distribution as well as the presence of trap states in an
organic material. The consequences resulting from the model are discussed
exemplarily on the basis of an indium tin oxide/organic semiconductor/metallic
conductor structure. A comparison of the theory to experimental data of a
unipolar indium tin oxide/poly-3-hexyl-thiophene/Al device is presented.Comment: 6 pages, 2 figures; to be published in Journal of Applied Physic
The Many Faces of a Character
We prove an identity between three infinite families of polynomials which are
defined in terms of `bosonic', `fermionic', and `one-dimensional configuration'
sums. In the limit where the polynomials become infinite series, they give
different-looking expressions for the characters of the two integrable
representations of the affine algebra at level one. We conjecture yet
another fermionic sum representation for the polynomials which is constructed
directly from the Bethe-Ansatz solution of the Heisenberg spin chain.Comment: 14/9 pages in harvmac, Tel-Aviv preprint TAUP 2125-9
Non-Simplified SUSY: Stau-Coannihilation at LHC and ILC
If new phenomena beyond the Standard Model will be discovered at the LHC, the
properties of the new particles could be determined with data from the
High-Luminosity LHC and from a future linear collider like the ILC. We discuss
the possible interplay between measurements at the two accelerators in a
concrete example, namely a full SUSY model which features a small stau_1-LSP
mass difference. Various channels have been studied using the Snowmass 2013
combined LHC detector implementation in the Delphes simulation package, as well
as simulations of the ILD detector concept from the Technical Design Report. We
investigate both the LHC and ILC capabilities for discovery, separation and
identification of various parts of the spectrum. While some parts would be
discovered at the LHC, there is substantial room for further discoveries at the
ILC. We finally highlight examples where the precise knowledge about the lower
part of the mass spectrum which could be acquired at the ILC would enable a
more in-depth analysis of the LHC data with respect to the heavier states.Comment: 42 pages, 18 figures, 12 table
Economic inequalities in burden of illness, diagnosis and treatment of five long-term conditions in England: panel study
We compared the distribution by wealth of self-reported illness burden (estimated from validated scales, biomarker and reported symptoms) for angina, cataract, depression, diabetes and osteoarthritis, with the distribution of self-reported medical diagnosis and treatment. We aimed to determine if the greater illness burden borne by poorer participants was matched by appropriately higher levels of diagnosis and treatment
Stationary Velocity and Charge Distributions of Grains in Dusty Plasmas
Within the kinetic approach velocity and charge distributions of grains in
stationary dusty plasmas are calculated and the relations between the effective
temperatures of such distributions and plasma parameters are established. It is
found that the effective temperature which determines the velocity grain
distribution could be anomalously large due to the action of accelerating ionic
bombarding force. The possibility to apply the results obtained to the
explanation of the increasing grain temperature in the course of the
Coulomb-crystal melting by reduction of the gas pressure is discussed. This
paper was received by Phys.Rev.Lett. on 11 August 1999. As potential referees
the authors offered to Editor the following persons: V.N.Tsytovich, Russia;
R.Bingham, UK; D.Resendes, Portugal; G.Morfill, P.Shukla, Y.M.Yu., Germany.Comment: 8 pages, no figure
Towards a Media Interpretation Framework for the Semantic Web
We present a framework for media interpretation that leverages low-level information extraction to a higher level of abstraction in
order to support semantics-based information
retrieval for the Semantic Web. The overall
goal of the framework is to provide high-level
content descriptions of documents for maximizing precision and recall of semantics-based
information retrieval
Charge carrier injection into insulating media: single-particle versus mean-field approach
Self-consistent, mean-field description of charge injection into a dielectric
medium is modified to account for discreteness of charge carriers. The improved
scheme includes both the Schottky barrier lowering due to the individual image
charge and the barrier change due to the field penetration into the injecting
electrode that ensures validity of the model at both high and low injection
rates including the barrier dominated and the space-charge dominated regimes.
Comparison of the theory with experiment on an unipolar ITO/PPV/Au-device is
presented.Comment: 32 pages, 9 figures; revised version accepted to PR
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