501 research outputs found
LevelScheme: A level scheme drawing and scientific figure preparation system for Mathematica
LevelScheme is a scientific figure preparation system for Mathematica. The
main emphasis is upon the construction of level schemes, or level energy
diagrams, as used in nuclear, atomic, molecular, and hadronic physics.
LevelScheme also provides a general infrastructure for the preparation of
publication-quality figures, including support for multipanel and inset
plotting, customizable tick mark generation, and various drawing and labeling
tasks. Coupled with Mathematica's plotting functions and powerful programming
language, LevelScheme provides a flexible system for the creation of figures
combining diagrams, mathematical plots, and data plots.Comment: LaTeX (RevTeX), 10 pages, associated files available from
http://wnsl.physics.yale.edu/levelschem
Explicit Solution to the N-Body Calogero Problem
We solve the N-body Calogero problem, \ie N particles in 1 dimension subject
to a two-body interaction of the form \half \sum_{i,j}[ (x_i - x_j)^2 + g/
{(x_i - x_j)^2}], by constructing annihilation and creation operators of the
form , where is
a modified momentum operator obeying %!!!!!!! Heisenberg-type commutation
relations with , involving explicitly permutation operators. On the other
hand, can be interpreted as a covariant derivative
corresponding to a flat connection. The relation to fractional statistics in
1+1 dimensions and anyons in a strong magnetic field is briefly discussed.Comment: 6 p., latex, USITP-92-
Nonrelativistic Factorizable Scattering Theory of Multicomponent Calogero-Sutherland Model
We relate two integrable models in (1+1) dimensions, namely, multicomponent
Calogero-Sutherland model with particles and antiparticles interacting via the
hyperbolic potential and the nonrelativistic factorizable -matrix theory
with -invariance. We find complete solutions of the Yang-Baxter
equations without implementing the crossing symmetry, and one of them is
identified with the scattering amplitudes derived from the Schr\"{o}dinger
equation of the Calogero-Sutherland model. This particular solution is of
interest in that it cannot be obtained as a nonrelativistic limit of any known
relativistic solutions of the -invariant Yang-Baxter equations.Comment: 4 pages, latex(uses Revtex), one figur
A class of Calogero type reductions of free motion on a simple Lie group
The reductions of the free geodesic motion on a non-compact simple Lie group
G based on the symmetry given by left- and right
multiplications for a maximal compact subgroup are
investigated. At generic values of the momentum map this leads to (new) spin
Calogero type models. At some special values the `spin' degrees of freedom are
absent and we obtain the standard Sutherland model with three
independent coupling constants from SU(n+1,n) and from SU(n,n). This
generalization of the Olshanetsky-Perelomov derivation of the model with
two independent coupling constants from the geodesics on with
G=SU(n+1,n) relies on fixing the right-handed momentum to a non-zero character
of . The reductions considered permit further generalizations and work at
the quantized level, too, for non-compact as well as for compact G.Comment: shortened to 13 pages in v2 on request of Lett. Math. Phys. and
corrected some spelling error
Strategies for Public Engagement with Official Statistics
High quality data are available on a very wide range of topics. However, there are barriers to be overcome before citizens engage with these data. First is access; data are often distributed across different websites. Second is exposure; data need to be presented in the most commonly used information sources. Third is engagement – creating a climate where citizens are interested in evidence. The House of Commons Library (Library) and Durham University are collaborating in order to promote better use of data. The Library is the first port of call for politicians; their blogs and tweets are a major information resource for journalists. A website created ahead of the UK general election provides a rich resource for data at constituency level. Quizzes have been created which run on smartphones, in an effort to engage a broader section of people in evidence-based discussions. We discuss strategies designed to encourage public engagement with official statistics
Designing Interactive Displays to Promote Effective use of Evidence
Interactive displays are increasing being used to convey information, and are a significant factor in promoting statistical literacy (and illiteracy). Durham University and the House of Commons Library are collaborating to create data visualisations (DV) which will be accessible to politicians, researchers and journalists. The focus of this paper is a DV designed to be useful in the run-up to the 2015 general election. The aim was to assemble a rich resource from multiple sources, and to make it easy for target groups to manipulate data and draw conclusions. We identify important changes to the DV as it evolved over 13 iterations, and draw conclusions about appropriate design processes and validation
Doping dependence of superconducting gap in YBa_2Cu_3O_y from universal heat transport
Thermal transport in the T -> 0 limit was measured as a function of doping in
high-quality single crystals of the cuprate superconductor YBa_2Cu_3O_y. The
residual linear term kappa_0/T is found to decrease as one moves from the
overdoped regime towards the Mott insulator region of the phase diagram. The
doping dependence of the low-energy quasiparticle gap extracted from kappa_0/T
is seen to scale closely with that of the pseudogap, arguing against a
non-superconducting origin for the pseudogap. The presence of a linear term for
all dopings is evidence against the existence of a quantum phase transition to
an order parameter with a complex (ix) component.Comment: 2 pages, 2 figures, submitted to M2S-Rio 2003 Proceeding
Self-similarity and novel sample-length-dependence of conductance in quasiperiodic lateral magnetic superlattices
We study the transport of electrons in a Fibonacci magnetic superlattice
produced on a two-dimensional electron gas modulated by parallel magnetic field
stripes arranged in a Fibonacci sequence. Both the transmission coefficient and
conductance exhibit self-similarity and the six-circle property. The presence
of extended states yields a finite conductivity at infinite length, that may be
detected as an abrupt change in the conductance as the Fermi energy is varied,
much as a metal-insulator transition. This is a unique feature of transport in
this new kind of structure, arising from its inherent two-dimensional nature.Comment: 9 pages, 5 figures, revtex, important revisions made. to be published
in Phys. Rev.
Field-induced thermal metal-to-insulator transition in underdoped LSCO
The transport of heat and charge in cuprates was measured in undoped and
heavily-underdoped single crystal La_{2-x}Sr_xCuO_{4+delta} (LSCO). In
underdoped LSCO, the thermal conductivity is found to decrease with increasing
magnetic field in the T --> 0 limit, in striking contrast to the increase
observed in all superconductors, including cuprates at higher doping. The
suppression of superconductivity with magnetic field shows that a novel thermal
metal-to-insulator transition occurs upon going from the superconducting state
to the field-induced normal state.Comment: 2 pages, 2 figures, submitted to M2S-Rio 2003 Proceeding
Moringa oleifera as a natural coagulant
The authors gratefully acknowledge the financial support of the Overseas Development Administration
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