Search results for "iTED"

Molecular excited state calculations with adaptive wavefunctions on a quantum eigensolver emulation: reducing circuit depth and separating spin states

2021

Ab initio electronic excited state calculations are necessary for the quantitative study of photochemical reactions, but their accurate computation on classical computers is plagued by prohibitive resource scaling. The Variational Quantum Deflation (VQD) is an extension of the quantum-classical Variational Quantum Eigensolver (VQE) algorithm for calculating electronic excited state energies, and has the potential to address some of these scaling challenges using quantum computers. However, quantum computers available in the near term can only support a limited number of quantum circuit operations, so reducing the quantum computational cost in VQD methods is critical to their realisation. In…

Faraday patterns in bose-Einstein condensates.

2002

Temporal periodic modulation of the interatomic s-wave scattering length in Bose-Einstein condensates is shown to excite subharmonic patterns of atom density through a parametric resonance. The dominating wavelength of the spatial structures is shown to be primarily selected by the excitation frequency but also affected by the depth of the spatial modulation via a nonlinear resonance. These phenomena represent macroscopic quantum analogues of the Faraday waves excited in vertically shaken liquids.

Directional Second Harmonic Generation Controlled by Sub-wavelength Facets of an Organic Mesowire

2018

Directional harmonic generation is an important property characterizing the ability of nonlinear optical antennas to diffuse the signal in well-defined region of space. Herein, we show how sub-wavelength facets of an organic molecular mesowire crystal can be utilized to systematically vary the directionality of second harmonic generation (SHG) in the forward scattering geometry. We demonstrate this capability on crystalline diamonoanthraquinone (DAAQ) mesowires with subwavelength facets. We observed that the radial angles of the SHG emission can be tuned over a range of 130 degrees. This angular variation arises due to spatially distributed nonlinear dipoles in the focal volume of the excit…

Shoah y Spielberg: 25 años de un modelo narrativo para contar el Holocausto

2020

La lista de Schindler representó un punto de inflexión en la narrativa sobre el Holocausto. A pesar de que fue bien recibida por crítica y público, algo nada habitual en la trayectoria de un Steven Spielberg al que se tildaba de autor infantil y bueno sólo como realizador de cine de aventuras, la película no lo fue tanto en los círculos intelectuales judíos. La crítica negativa a la fábula cruel pero esperanzada de Spielberg fue ejercida especialmente por el director de otra de las propuestas cinematográficas que desde el extremo opuesto formalmente, también sentó referencia en el género: Claude Lanzmann y su monumental Shoah. Ahora, un cuarto de siglo después, queremos analizar en este art…

An E-plane EBG waveguide for dispersion compensated transmission of short pulses

2007

The resolution of radar applications can significantly suffer from pulse broadening along the propagation in homogeneous hollow waveguides. The latter occurs due to the strongly dispersive nature of the fast waves in the waveguides. A low-cost solution to this problem is here proposed, employing an EBG type of waveguide, compatible with traditional E-plane fabrication techniques. By means of an example, here we demonstrate the reduction of the pulse spreading as it propagates along this type of waveguide.

What are the risk and protective factors for the well-being of adolescents with CF?

2021

La fibrosis quística (FQ) es una enfermedad crónica y hereditaria que compromete la vida de quienes la padecen, y se hace especialmente importante su impacto en la adolescencia. El afrontamiento que estos pacientes y sus familiares hagan de estas circunstancias que les han tocado vivir, puede mejorar o empeorar el curso y desenlace de la enfermedad. El objetivo es conocer los factores de riesgo y protectores que influyen en el bienestar de los adolescentes con FQ. Para ello se realizó una búsqueda bibliográfica de la literatura científica siguiendo la guía PRISMA en las siguientes bases de datos: Web of Science, ProQuest y Scopus. Se incluyeron artículos centrados en factores psicológicos d…

Cover Feature: Excited‐State Kinetics of an Air‐Stable Cyclometalated Iron(II) Complex (Chem. Eur. J. 51/2019)

2019

High spatiotemporal resolution in multifocal processing with femtosecond laser pulses.

2006

We report spatial and temporal dispersion compensation for fan-out of femtosecond pulses with a low-frequency diffraction grating by means of a hybrid diffractive-refractive lens triplet. In this way, we achieve a multifocal light structure with nearly diffraction-limited light spots even for 20 fs pulse duration. The spatial chromatic compensation, which drastically reduces the lateral walk-off of the various spectral components, also allows us to improve the available bandwidth at the dispersion-compensated diffraction orders. In fact, the temporal width of the output pulse is essentially limited by the group-delay dispersion term, which is shown to be small. The high spatiotemporal resol…

All-fibered high-quality 1.5–2 THz femtosecond pulse sources

2009

Generation of high-quality ultra-high repetition rate optical pulse trains around 1.55µm has become increasingly interesting for many scientific applications such as optical sampling, ultra-high capacity transmission systems, component testing or nonlinear phenomena studies. Unfortunately, the current bandwidth limitations of optoelectronic devices do not enable the direct generation of pulses with repetition rate higher than 80GHz and a temporal width below a few ps.

Fiber-based device for the detection of low-intensity fluctuations of ultrashort pulses

2012

International audience; We describe a fiber-based device that can significantly enhance the low intensity fluctuations of an ultrashort pulse train to detect them more easily than with usual direct detection systems. Taking advantage of the Raman intrapulse effect that progressively shifts the central frequency of a femtosecond pulse propagating in an anomalous dispersion fiber, a subsequent spectral filtering can efficiently increase the level of fluctuations by more than one order of magnitude. We show that attention has to be paid to maintain the shape of the statistical distribution unaffected by the nonlinear process.