1,208 research outputs found
Journal Publishers Approaches to Self-Archiving and Open Access : ZIM Briefing Paper
Overview - Analysis of 80 scholarly publishers' copyright agreements - Selected examples from major publishers regarding self-archiving - Selected Reading and selected websites - Appendix A: Analysis of Copyright Transfer Agreements (CTA) and/or Licences of commercial Publishers and Learned Societies-Extract
Smoothed Complexity Theory
Smoothed analysis is a new way of analyzing algorithms introduced by Spielman
and Teng (J. ACM, 2004). Classical methods like worst-case or average-case
analysis have accompanying complexity classes, like P and AvgP, respectively.
While worst-case or average-case analysis give us a means to talk about the
running time of a particular algorithm, complexity classes allows us to talk
about the inherent difficulty of problems.
Smoothed analysis is a hybrid of worst-case and average-case analysis and
compensates some of their drawbacks. Despite its success for the analysis of
single algorithms and problems, there is no embedding of smoothed analysis into
computational complexity theory, which is necessary to classify problems
according to their intrinsic difficulty.
We propose a framework for smoothed complexity theory, define the relevant
classes, and prove some first hardness results (of bounded halting and tiling)
and tractability results (binary optimization problems, graph coloring,
satisfiability). Furthermore, we discuss extensions and shortcomings of our
model and relate it to semi-random models.Comment: to be presented at MFCS 201
Recoil correction to the bound-electron g factor in H-like atoms to all orders in
The nuclear recoil correction to the bound-electron g factor in H-like atoms
is calculated to first order in and to all orders in . The
calculation is performed in the range Z=1-100. A large contribution of terms of
order and higher is found. Even for hydrogen, the higher-order
correction exceeds the term, while for uranium it is above the
leading correction.Comment: 6 pages, 3 tables, 1 figur
Toward high-precision values of the self energy of non-S states in hydrogen and hydrogen-like ions
The method and status of a study to provide numerical, high-precision values
of the self-energy level shift in hydrogen and hydrogen-like ions is described.
Graphs of the self energy in hydrogen-like ions with nuclear charge number
between 20 and 110 are given for a large number of states. The self-energy is
the largest contribution of Quantum Electrodynamics (QED) to the energy levels
of these atomic systems. These results greatly expand the number of levels for
which the self energy is known with a controlled and high precision.
Applications include the adjustment of the Rydberg constant and atomic
calculations that take into account QED effects.Comment: Minor changes since previous versio
Recommended from our members
A proposal to study particle production spectra and multiplicities in high energy hadron-hadron collisions, and for a beam survey and quark search
We propose an experimental study at the new 500 GeV accelerator of the differential cross-section for particle production in hadron-hadron collisions. The projectile, and the observed single particle, will range over all combinations of positive and negative {pi}, K and p, with momenta extending up to the highest available. Enough of the secondary particle momentum range will be covered to permit us to determine by integration the multiplicity of the produced particle. Single particles will be detected in a simple spectrometer consisting of wire chambers and a small bending magnet. The configuration of the spectrometer components will be variable so that the overall spectrometer length can be kept proportional to the secondary momentum. The momentum resolution {male}P/P = {+-}0.8% and the invariant phase space acceptance P{sup 2}d{Omega}dP/E = 1.3x10{sup -3} (GeV/c){sup 2} will then be the same at all momenta. Particle identification will be by means of threshold Cherenkov counters, with 10{sup 4}: 1 rejection up to at least 250 GeV/c. Our experimental arrangement is thought to be simple and yet powerful, and we propose its use initially with incident protons and a nuclear target for a beam survey and quark search. Subsequent measurements will be carried out with a hydrogen target in a high intensity secondary beam
Finite nuclear size and Lamb shift of p-wave atomic states
We consider corrections to the Lamb shift of p-wave atomic states due to the
finite nuclear size (FNS). In other words, these are radiative corrections to
the atomic isotop shift related to FNS. It is shown that the structure of the
corrections is qualitatively different from that for s-wave states. The
perturbation theory expansion for the relative correction for a -state
starts from -term, while for -states it starts
from term. Here is the fine structure constant and is
the nuclear charge. In the present work we calculate the -terms for
-states, the result for -state reads
. Even more interesting are
-states. In this case the ``correction'' is by several orders of
magnitude larger than the ``leading'' FNS shift.Comment: 4 pages, 2 figure
Технико-экономические и экологические аспекты утилизация шламов, содержащих соединения цинка
По причине токсичности перед сбросом в водоемы ионы цинка выделяются из сточных вод в виде твердых соединений, которые осаждаются в виде шлама в прудах-накопителях. Приведены данные по количественному и качественному составам шлама в накопителеотстойнике предприятия по производству вискозного волокна. Отмечено, что такой накопитель в г. Красноярске является техногенным образованием содержащем ценное сырье - цинк. Поэтому необходима разработка и внедрение технологий переработки и утилизации цинксодержащих шламов различных производств.Zinc ions are toxic and they are isolated from sewage in the form of solid compounds before discharge into water bodies. Precipitation occurs in the form of slime in storage ponds. Data on the quantitative and qualitative composition of the sludge in the reservoir-settler of an enterprise for the production of viscose fiber are given. It is noted that such a storage facility in Krasnoyarsk is a technogenic for mation containing valuable raw materials - zinc. Therefore, it is necessary to develop and implement technologies for processing and utilization of zinc-containing slurries of various industries
HITRAP: A facility at GSI for highly charged ions
An overview and status report of the new trapping facility for highly charged
ions at the Gesellschaft fuer Schwerionenforschung is presented. The
construction of this facility started in 2005 and is expected to be completed
in 2008. Once operational, highly charged ions will be loaded from the
experimental storage ring ESR into the HITRAP facility, where they are
decelerated and cooled. The kinetic energy of the initially fast ions is
reduced by more than fourteen orders of magnitude and their thermal energy is
cooled to cryogenic temperatures. The cold ions are then delivered to a broad
range of atomic physics experiments.Comment: 8 pages, 11 figure
Factors controlling regional differences in forest soil emission of nitrogen oxides (NO and N2O)
Peer reviewe
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