38,305 research outputs found
Evaluations of k-fold Euler/Zagier sums: a compendium of results for arbitrary k
Euler sums (also called Zagier sums) occur within the context of knot theory
and quantum field theory. There are various conjectures related to these sums
whose incompletion is a sign that both the mathematics and physics communities
do not yet completely understand the field. Here, we assemble results for
Euler/Zagier sums (also known as multidimensional zeta/harmonic sums) of
arbitrary depth, including sign alternations. Many of our results were obtained
empirically and are apparently new. By carefully compiling and examining a huge
data base of high precision numerical evaluations, we can claim with some
confidence that certain classes of results are exhaustive. While many proofs
are lacking, we have sketched derivations of all results that have so far been
proved.Comment: 19 pages, LaTe
Tripartite entanglement from interlinked parametric interactions
We examine the tripartite entanglement properties of an optical system using
interlinked interactions, recently studied experimentally in terms
of its phase-matching properties by Bondani et al [M. Bondani, A. Allevi, E.
Gevinti, A. Agliati, and A. Andreoni, arXiv:quant-ph/0604002.]. We show that
the system does produce output modes which are genuinely tripartite entangled
and that detection of this entanglement depends crucially on the correlation
functions which are measured, with a three-mode Einstein-Podolsky-Rosen
inequality being the most sensitive.Comment: 15 pages, 5 figure
Scientific publications and presentations relating to planetary quarantine. Volume 5: The 1972 supplement
The sixth annual supplement to the bibliography on planetary quarantine contains 191 references, an author index and a permuted title index
Axistationary perfect fluids -- a tetrad approach
Stationary axisymmetric perfect fluid space-times are investigated using the
curvature description of geometries. Attention is focused on space-times with a
vanishing electric part of the Weyl tensor. It is shown that the only
incompressible axistationary magnetic perfect fluid is the interior
Schwarzschild solution. The existence of a rigidly rotating perfect fluid,
generalizing the interior Schwarzschild metric is proven. Theorems are stated
on Petrov types and electric/magnetic Weyl tensors.Comment: 12 page
How Well Does "Core" CPI Capture Permanent Price Changes?
We decompose core CPI and the food and energy CPI measures into permanent and transitory components using a correlated unobserved components model, to examine the behavior of core CPI when subject to shocks and to examine the claim that core CPI captures the persistent part of headline CPI. We find that the permanent component of core CPI is more volatile than core CPI, or that the permanent and transitory components are highly correlated. We find that the excluded food and energy components have important permanent components, and that core CPI has an important transitory component. We examine impulse response functions and find that headline CPI inflation responds more sharply to shocks than core CPI inflation, and after the first year the impact of shocks on headline inflation is less than the impact on core inflation.unobserved components, CPI, price indices, inflation, core
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