85,668 research outputs found
Status and Prospects for the AWAKE Experiment
The AWAKE Collaboration is pursuing a demonstration of proton-driven plasma
wakefield acceleration of electrons. The AWAKE experiment uses a
\SI{400}{GeV/c} proton bunch from the CERN SPS, with a rms bunch length of
-\SI{15}{cm}, to drive wakefields in a \SI{10}{m} long rubidium plasma with
an electron density of cm. Since the drive bunch length
is much longer than the plasma wavelength (\SI{3}{mm}) for these
plasma densities, AWAKE performed experiments to prove that the long proton
bunch self-modulates in the plasma (2017). The next step is to demonstrate
acceleration of electrons in the wakefields driven by the self-modulated bunch
(2018). We summarize the concept of the self-modulation measurements and
describe the plans and challenges for the electron acceleration experiments
On simplicial commutative algebras with Noetherian homotopy
In this paper, a strategy is developed studying a simplicial commutative
algebra A whose zeroth homotopy group is a Noetherian ring B and whose higher
homotopy groups are finite over B. The strategy replaces A with a connected
simplicial supplemented k(q)-algebra, for each prime ideal q in B, which
preserves much of the Andre-Quillen homology of A. The methods for this
construction involves a mixture of methods of homotopy theory (e.g. Postnikov
towers) with methods of commutative algebras (e.g. completions, Cohen
factorizations). We finish by indicating how these methods resolve a more
general form of a conjecture posed by Quillen.Comment: 10 page
Simplicial commutative algebras with vanishing Andre-Quillen homology
In this paper, we study the Andr\'e-Quillen homology of simplicial
commutative -algebras, a field, having certain vanishing
properties. When has non-zero characteristic, we obtain an algebraic
version of a theorem of J.-P. Serre and Y. Umeda that characterizes such
simplicial algebras having bounded homotopy groups. We further discuss how this
theorem fails in the rational case and, as an application, indicate how the
algebraic Serre theorem can be used to resolve a conjecture of D. Quillen for
algebras of finite type over Noetherian rings, which have non-zero
characteristic.Comment: 11 page
Chemical structure matching using correlation matrix memories
This paper describes the application of the Relaxation By Elimination (RBE) method to matching the 3D structure of molecules in chemical databases within the frame work of binary correlation matrix memories. The paper illustrates that, when combined with distributed representations, the method maps well onto these networks, allowing high performance implementation in parallel systems. It outlines the motivation, the neural architecture, the RBE method and presents some results of matching small molecules against a database of 100,000 models
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