Search results for " CLUSTER"
showing 10 items of 2162 documents
Automated detection of contextuality proofs with intermediate numbers of observables
2021
<div style=""><font face="arial, helvetica"><span style="font-size: 13px;">Quantum contextuality takes an important place amongst the concepts of quantum computing that bring an advantage over its classical counterpart. For a large class of contextuality </span></font><span style="font-size: 13px; font-family: arial, helvetica;">proofs, aka. observable-based proofs of the Kochen-Specker Theorem, we first formulate the</span></div><div style=""><font face="arial, helvetica"><span style="font-size: 13px;">contextuality property as the absence of solutions to a linear system. Then we explain why </span></font><span style="font-size: 13px; font-family: arial, helvetica…
A Route toward Protein Sequencing using Solid-State Nanopores Assisted by Machine Learning
2022
Solid-State Nanopores made of 2-D materials such as MoS2 have emerged as one of the most versatile sensors for single-biomolecule detection, which is essential for early disease diagnosis (biomarker detection). One of the most promising applications of SSN is DNA and protein sequencing, at a low cost and faster than the current standard methods. The detection principle relies on measuring the relatively small variations of ionic current as charged biomolecules immersed in an electrolyte traverse the nanopore, in response to an external voltage applied across the membrane. The passage of a biomolecule through the pore yields information about its structure and chemical properties, as demonst…
Computer-assisted enumeration and classification of multi-qubit doilies
2022
For N ≥ 2, an N-qubit doily is a doily living in the N-qubit symplectic polar space. These doilies are related to operator-based proofs of quantum contextuality. Following and extending the strategy of [SdBHG21] that focused exclusively on three-qubit doilies, we first bring forth several formulas giving the number of both linear and quadratic doilies for any N > 2. Then we present an effective algorithm for the generation of all N-qubit doilies. Using this algorithm for N = 4 and N = 5, we provide a classification of N-qubit doilies in terms of types of observables they feature and number of negative lines they are endowed with.
A Hirshfeld partitioning of polarizabilities of water clusters
2006
International audience; A new Hirshfeld partitioning of cluster polarizability into intrinsic polarizabilities and charge delocalization contributions is presented. For water clusters, density-functional theory calculations demonstrate that the total polarizability of a water molecule in a cluster depends upon the number and type of hydrogen bonds the molecule makes with its neighbors. The intrinsic contribution to the molecular polarizability is transferable between water molecules displaying the same H-bond scheme in clusters of different sizes, and geometries, while the charge delocalization contribution also depends on the cluster size. These results could be used to improve the existin…
MOLECULAR LINE-SHAPE MODELING FROM FIRST PRINCIPLES
2015
International audience; We present an ab initio approach to spectral line-shape modeling and the comparison of the results with experimental data.
Quasi-soliton spatial autoguidé en milieu non lineaire quadratique
2021
International audience; Nous démontrons ici des phénomènes d'autoguidage optique existant dans les milieux à non-linéarités quadratiques. En plus de la formation puis disparition d'un phénomène auto confiné, nous observons des effets de commutation ultrarapide et de démultiplication spatiale, ainsi qu'une restructuration temporelle suivie d'élargissements spectraux.
All-optical fiber-based devices for ultrafast amplitude jitter magnification
2012
International audience; We propose two fiber-based architectures that enable the all-optical magnification of ultrafast amplitude fluctuations of picosecond or femtosecond pulse trains. An increase of the fluctuations by more than one order of magnitude is experimentally achieved.
Wavelength dependence of multiphoton ionization of xenon
2004
International audience; We have studied the multiphoton ionization of xenon atoms by 160 fs pulses at intensities of 531012 and 1.331013 W/cm2 and present photoelectron kinetic energy and angular distribution spectra measured with a photoelectron imaging spectrometer. A noncollinear optical parametric amplifier allows us to tune the wavelength of the laser pulse over a range between 500 and 700 nm. Resonant and nonresonant processes as well as channel switching effects have been observed in this intensity and wavelength regime. Mainly resonant s5+1d-photon ionization via ns, nd, and nd8 Rydberg states was studied in the region of 505–602 nm. Resonance structures were found related to the tw…
Echo-assisted impulsive alignment of room-temperature acetone molecules
2021
International audience; We experimentally and theoretically investigate the field-free alignment of the asymmetric-top acetone molecule. Our study shows that the production of postpulse aligned molecules in a dense sample (0.05-0.2 bar) of room-temperature acetone using a single-pulse excitation can be significantly improved by rotational alignment echoes induced in a two-pulse excitation scheme. We report the observation of fractional echoes that can be used to reveal the nonlinearity of the molecular system. In a proof-of-principle experiment, a pre-aligned sample of acetone is also used for third-harmonic generation. The analysis of the experimental data with numerical simulations based …
Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei
2008
Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the ighest-energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science 318 (2007) 938]. The correlation has maximum significance for cosmic rays with energy greater than ~6 x 1019 eV and AGN at a distance less than ~75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with parameters specified a priori, using an independent data set. The observed correlation is compatible with the hypothesis that cosmic rays with the highest-energies originate fro…