Search results for "polarization."
showing 10 items of 1842 documents
Probing the nature of particle–core couplings in 49Ca with γ spectroscopy and heavy-ion transfer reactions
2011
Neutron rich nuclei around 48Ca have been measured with the CLARA–PRISMA setup, making use of 48Ca on 64Ni binary reactions, at 5.9 MeV/A. Angular distributions of γ rays give evidence, in several transfer channels, for a large spin alignment (≈70%) perpendicular to the reaction plane, making it possible to firmly establish spin and parities of the excited states. In the case of 49Ca, states arising from different types of particle–core couplings are, for the first time, unambiguously identified on basis of angular distribution, polarization and lifetime measurements. Shell model and particle–vibration coupling calculations are used to pin down the nature of the states. Evidence is found fo…
Ferromagnetic Coupling through Spin Polarization in a Dinuclear Copper(II) Metallacyclophane.
2001
[DT] Von organischen Radikalen zu Metallkomplexen konnte das bekannte Konzept für Ferroelektrika erfolgreich ausgedehnt werden: Die Abbildung zeigt ein Cyclophan-artiges Molekül mit einem Triplett-Grundzustand, in dem zwei CuII-Zentren von einem doppelten m-Phenylendiamid-Gerüst zusammengehalten werden.
Reducing the gap between leaders and voters? Elite polarization, outbidding competition, and the rise of secessionism in Catalonia
2016
ABSTRACTThe ethnic outbidding thesis explains party polarization as a consequence of political changes amongst voters. We argued instead that party elites’ extreme position on the national identity cleavage can help polarizing strategies to prevail over moderate strategies in a context of increasing political uncertainty, without previous voters’ polarization. We test successfully this hypothesis in Catalonia by analysing the polarization of political parties and people’s demands for self-government in Catalonia since the early 2000s. We also find that the result of this outbidding pattern of competition was a reduction in the gap between elites’ and voters’ views on national identity. The …
Pamięci nieukojone. Wokół upamiętniania ofiar w Serbii i Chorwacji (Jasenovac, Bleiburg i belgradzkie Sajmište)
2016
Tekst koncentruje się na przemianach tożsamości narodowych w dwóch krajach postjugosłowiańskich (Serbii i Chorwacji). (Re)konstrukcje przeszłości mające tam miejsce od lat dziewięćdziesiątych XX wieku zakładały przede wszystkim zanegowanie dziedzictwa wspólnego opartego na zmitologizowanej walce partyzanckiej, a następnie wybór z przeszłości tych wydarzeń, o których pamięć należy kultywować. Walka przeciwstawnych pamięci (serbskiej i chorwackiej) oraz polaryzacja społeczeństwa chorwackiego pokazana zostaje na przykładzie praktyk komemoratywnych związanych z miejscami zagłady (Jasenovac i Bleiburg) z okresu drugiej wojny światowej. W tekście przywołano również miejsce kojarzone z Holokaustem…
Geometric phase induced by a cyclically evolving squeezed vacuum reservoir
2006
We propose a new way to generate an observable geometric phase by means of a completely incoherent phenomenon. We show how to imprint a geometric phase to a system by "adiabatically" manipulating the environment with which it interacts. As a specific scheme we analyse a multilevel atom interacting with a broad-band squeezed vacuum bosonic bath. As the squeezing parameters are smoothly changed in time along a closed loop, the ground state of the system acquires a geometric phase. We propose also a scheme to measure such geometric phase by means of a suitable polarization detection.
Rotational Raman spectroscopy of ethylene using a femtosecond time-resolved pump-probe technique.
2005
154309; Femtosecond Raman-induced polarization spectroscopy (RIPS) was conducted at low pressure (250 mb at 295 K and 400 mb at 373 K) in ethylene. The temporal signal, resulting from the beating between pure rotational coherences, was measured with a heterodyne detection. The temporal traces were converted to the frequency domain using a Fourier transformation and then analyzed thanks to the D2hTDS software (http://www.u-bourgogne.fr/LPUB/shTDS.html) dedicated to X2Y4 molecules with D2h symmetry. The effective Hamiltonian was expanded up to order 2, allowing the determination of five parameters with an rms of 0.017 cm(-1). Special care was taken in the precise modeling of intensities, taki…
Polarization-domain-wall complexes in fiber lasers
2013
To study the possible build-up of polarization-domain-walls (PDWs) in fiber laser cavities, an erbium-doped fiber ring laser was used and a wide range of vector polarization dynamics that can be selected at a given pump power, by using the degrees of freedom of two intracavity polarization controllers (PC) was investigated. A simple theoretical model that explains polarization switching in fiber ring lasers featuring a normally dispersive cavity with a typical, moderate, level of birefringence is presented. Such polarization dynamics, based on a special class of polarization-domain-wall structures, agrees qualitatively well with experimental observations. The paper stresses on the complex a…
Hamiltonian tools for the analysis of optical polarization control
2011
Import JabRef; International audience; The study of the polarization dynamics of two counterpropagating beams in optical fibers has recently been the subject of a growing renewed interest, from both the theoretical and experimental points of view. This system exhibits a phenomenon of polarization attraction, which can be used to achieve a complete polarization of an initially unpolarized signal beam, almost without any loss of energy. Along the same way, an arbitrary polarization state of the signal beam can be controlled and converted into any other desired state of polarization, by adjusting the polarization state of the counterpropagating pump beam. These properties have been demonstrate…
Nonintrusive monitoring and quantitative analysis of strong laser-field-induced impulsive alignment
2004
We report the observation of impulsive alignment of $\mathrm{C}{\mathrm{O}}_{2}$ molecules produced through their interaction with a nonresonant, strong laser pulse. The periodic alignment is monitored using a polarization technique generally employed in optical Kerr effect experiments; the birefringence produced by alignment of the molecular sample is measured with a weak pulse, time-delayed with respect to the alignment pulse. The technique provides a signal proportional to $⟨{\mathrm{cos}}^{2}\phantom{\rule{0.2em}{0ex}}\ensuremath{\theta}⟩\ensuremath{-}\frac{1}{3}$, where $\ensuremath{\theta}$ is the polar angle between the molecular axis and the strong-field polarization axis. Experimen…
Application of time-resolved spectroscopy to concentration measurements in gas mixtures
2001
1296-2147; Concentration measurements using femtosecond Raman Induced Polarization Spectroscopy (RIPS) are performed in binary gas mixtures CO2-N2 and CO2-N2O at room temperature. The principle of these measurements is based on the nonlinear rotational time response of each molecular component of the mixture, The general form of this molecular response is a series of periodic transients with a period related to the rotational constant Be The relative strength of the individual responses allows an accurate determination of the concentration. Two techniques are presented using either two pulses (one pump and one probe) or three pulses (two pumps and one probe). (C) 2001 Academie des sciences/…