Search results for " duration"
showing 10 items of 221 documents
All-sky search for long-duration gravitational wave transients in the first Advanced LIGO observing run
2018
Made available in DSpace on 2018-11-26T17:45:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-22 Australian Research Council Council of Scientific and Industrial Research of India Department of Science and Technology, India Science AMP; Engineering Research Board (SERB), India Ministry of Human Resource Development, India Spanish Agencia Estatal de Investigacion Vicepresidencia i Conselleria d'Innovacio, Recerca i Turisme Conselleria d'Educacio i Universitat del Govern de les Illes Balears Conselleria d'Educacio, Investigacio, Cultura i Esport de la Generalitat Valenciana National Science Centre of Poland Swiss National Science Foundation (SNSF) Russian Foundation for Basic Rese…
GRB 101225A - a new class of GRBs?
2012
AbstractThe Christmas burst, GRB 101225A, was one of the most controversial bursts in the last few years. Its exceptionally long duration but bright X-ray emission showing a thermal component followed by a strange afterglow with a thermal SED lead to two different interpretations. We present here our model ascribing this strange event to a new type of GRB progenitor consisting of a neutron star and an evolved main-sequence star in a very faint galaxy at redshift 0.33 while Campana et al. (2011) proposed a Galactic origin. New observations at several wavelengths might resolve the question between the two models in the near future.
Nonlinear spectral compression in fibre as a power-limiting device
2017
Spectral compression (SC) by self-phase modulation in optical fibre has been known for a long time and has since been reported for various parameters [1]. In this paper, we analyse the impact of amplitude fluctuations and a degraded optical signal-to-noise ratio (OSNR) of the seed pulses on the SC process by means of extensive nonlinear Schrodinger equation numerical simulation. Remarkably, our results show that the SC is rather stable against these pulse degradation factors, thereby revealing its potential for use in the context of optical regeneration of intensity-modulated signals. We therefore propose an optical scheme combining SC with an optical bandpass filter (OBPF) centred at the c…
Development and test of iron-free quadrupole lenses with high magnetic flux densities
2003
Abstract Iron-free magnetic quadrupole lenses have been developed for the focusing of energetic bunched heavy-ion beams. These devices are operated in a pulsed mode and provide very strong magnetic fields. A magnetic flux density of more than 14 T has been reached in a 100 mm long quadrupole with a 20 mm wide aperture, which corresponds to a magnetic flux density of ∼1400 T/m. The pulse duration of the applied electric current is approximately 300 μs with a flat top of several μs. The calculated and measured field properties of the quadrupoles are presented. In a first test experiment with a fast-extracted 650 MeV/u 197 Au 79+ beam (bunch length ∼500 ns) at GSI the focusing properties could…
The nonlinear optical loop mirror: soliton and noise-like pulse emission in a figure-eight fiber laser
2021
In this article, a symmetrical nonlinear optical loop mirror (NOLM) exhibiting a polarization-dependent transmission is evaluated to generate optical pulse emission in a figure-eight fiber laser in the soliton and noise-like pulse (NLP) regimes. The NOLM structure relies on a 50:50 fiber coupler, a loop with highly twisted single-mode optical fiber and a quarter-wave retarder (QWR) to break the polarization asymmetry. The pulse operation regime is determined by properly adjusting the NOLM low-power transmission, which is easily realized by the rotation of the QWR angle. Soliton pulses of 1.48 ps pulse duration and peak power of 18 W were observed with a peak to peak separation of 1.25 µs, c…
Fast ion swapping for quantum-information processing
2016
We demonstrate a swap gate between laser-cooled ions in a segmented microtrap via fast physical swapping of the ion positions. This operation is used in conjunction with qubit initialization, manipulation, and readout and with other types of shuttling operations such as linear transport and crystal separation and merging. Combining these operations, we perform quantum process tomography of the swap gate, obtaining a mean process fidelity of 99.5(5)%. The swap operation is demonstrated with motional excitations below 0.05(1) quantum for all six collective modes of a two-ion crystal for a process duration of $42\ensuremath{\mu}\mathrm{s}$. Extending these techniques to three ions, we reverse …
A NOT gate in a cis-trans photoisomerization model
2007
We numerically study the implementation of a NOT gate by laser pulses in a model molecular system presenting two electronic surfaces coupled by non adiabatic interactions. The two states of the bit are the fundamental states of the cis-trans isomers of the molecule. The gate is classical in the sense that it involves a one-qubit flip so that the encoding of the outputs is based on population analysis which does not take the phases into account. This gate can also be viewed as a double photo-switch process with the property that the same electric field controls the two isomerizations. As an example, we consider one-dimensional cuts in a model of the retinal in rhodopsin already proposed in t…
BeppoSAX observation of a large long-duration X-ray flare from UX Arietis
2001
We present two X-ray observations of the RS CVn binary system UX Arietis performed with BeppoSAX in August 1997 and August 1998. A large flare lasting for about 1 day was detected during the rst observation, while the star was quiescent during the second one. Hard X-ray emission up to50 keV was detected in the PDS instrument during the rise and at the peak of the flare. Time-resolved spectroscopy of the flare with the LECS and MECS detectors shows that temperatures as high as 100 MK were reached at the flare peak; such high temperatures are responsible for the high-energy tail seen in the PDS. We conrm that the coronal abundance of UX Ari is strongly subsolar (Z=Z' 0:2 0:3); no signicant va…
Stimulated nutation echo: application to the driven decoherence study
2003
We study experimentally the dynamical and decay properties of the stimulated nutation echo (SNE) in a two-level spin system, the signal of which allows the observation timescale of the driven coherence relaxation to be extended. This signal appears in the transient response of the system to the second pulse at time τ1 from its start and coinciding with the duration of the first pulse. The information about the first pulse duration is imprinted into the population difference of the inhomogeneously broadened ensemble of the two-level absorbers. The decay of the SNE signal has two contributions. One originates from the population decay during the time τ between the two pulses. Another is cause…
Pulse-duration dependence of the isotopic effect in simple molecular ions driven by strong laser fields
2011
In this paper we discuss isotopic effects in simple molecular ions subjected to strong laser fields. We show that the intensity of the emitted spectra strongly depends upon both the nuclear mass of the molecular ions and the laser pulse duration. In particular, for short pulse duration [up to 8 optical cycles (o.c.)], we confirm the trend described in the most studied case in which the high-order harmonic generation is more efficient for heavier isotopes; in contrast, an interesting physical phenomenon is predicted for pulses longer than 16 o.c. characterized by an inverse effect in which lighter molecular species are responsible for higher-order harmonic emission.