Search results for "Database"

On cosmic quantum tunneling from “nothing”

2015

We extend to a general Λ-Eriedmann-Lemaitre-Robertson-Walker (ΛFLRW) a previous result by Vilenkin and others according to which a closed de Sitter universe could be created from "nothing". More specifically, our main result is that only the closed ΛFLRW universe (but not the open and flat ones) could be created from a corresponding instanton, that is, from the corresponding solution with signature +4 of the Einstein field equations. Before getting this result the suitable corresponding instantons are calculated. The result is in accordance with previous results by another authors obtained by different methods.

Jet transition values for the anti-$$k_{\bot }$$ k⊥ algorithm

2019

We define jet transition values for the anti-$k_{\bot}$ algorithm for both hadron and $e^+e^-$ colliders. We show how these transition values can be computed and how they can be used to improve the performance of clusterization when jet resolution parameters are varied over a larger set of values. Finally we present a simple performance test to illustrate the behavior of the new method compared to the original one.

COOL, LCG Conditions Database for the LHC Experiments: Development and Deployment Status

2008

The Large Hadron Collider (LHC), the world’s largest and highest-energy particle accelerator, designed to collide opposing beams of protons or lead ions, started its operations in September 2008 at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland. To process and analyze the huge amounts of data generated by the four experiments installed at different collision points along the LHC ring, a large distributed computing infrastructure has been set up, the LHC Computing Grid (LCG). The bulk of this data, referred to as ‘event data’, will record the signals left in the sub-detectors of the four LHC experiments by the passage of the particles generated in the collision …

Essential Spectra Under Perturbations

2018

The spectrum of a bounded linear operator on a Banach space X can be sectioned into subsets in many different ways, depending on the purpose of the inquiry.

Experimental observation of incoherent modulation instability in standard optical fibers

2005

In this work, we demonstrate theoretically and experimentally that a partially temporally incoherent light can exhibit modulational instability when propagating in an optical fiber with instantaneous nonlinear Kerr response.

Another way of looking at the sky: Neutrino telescopes

2016

Neutrinos are weakly-interacting neutral particles, which makes them powerful sources of information about the most energetic processes in the universe, such as the origin of ultra-energetic cosmic rays or gamma-ray bursts. However, a price must be paid in order to detect them: gargantuan detectors at the bottom of the sea or under the Antarctic ice are required. The detection of the first high-energy cosmic neutrinos in 2013 by the IceCube observatory represented the start of so-called neutrino astronomy, a new way of observing the universe, which can play a key role in future discoveries. In this article, we describe how neutrino telescopes work, as well as the different initial configura…

High-multiplicity neutron events registered by NEMESIS experiment

2021

Neutron-induced interactions contribute to the signal-mimicking background in deep-underground searches for exotic phenomena such as Dark Matter, neutrino-less double beta decay, proton decay, etc. Apart from radioactive decay, the primary source of neutrons underground are high-energy muons from cosmic showers. While the maximum number of fission neutrons is around six and energies around one MeV, muon-induced interactions may generate hundreds of neutrons, also with high energies. Furthermore, these processes are not yet reproduced in numerical simulations with sufficient reliability. The main goal of the NEMESIS experiment is to improve our knowledge and understanding of cosmic muon-indu…

Book Review: One Dimensional and Two Dimensional NMR Spectra by Modern Pulse Techniques. Edited by K. Nakanishi

1992

Topological Defects in Nanostructures—Chiral Domain Walls and Skyrmions

2016

In this chapter, spin structures with particular topologies in confined geometries are presented. Domain walls in nanowires exhibit a spin structure that depends on the material and geometry while in discs Skyrmions can be stabilized by different competing interactions. The topologies of these spin structures can be characterized by a Skyrmion or Winding number that governs the dynamics and stability.

A Look at Some Remarkable Mathematical Techniques

1996

The nonlinear equations that we have encountered in the previous chapters can be solved by using mathematical techniques such as the powerful inverse scattering transform (IST) (Gardner et al. 1967) and the remarkable Hirota method (Hirota 1971). Specifically, in addition to the one-soliton solutions, explicit multisoliton solutions representing the interaction of any number of solitons can be constructed. Moreover, in several cases a precise prediction, closely related to experiments, can be made by the IST of the nonlinear response of the physical system, that is, of the number of solitons that can emerge from a finite initial disturbance (Zakharov, 1980. Ablowitz and Segur 1981; Calogero…