Search results for "WIG"
showing 10 items of 132 documents
Synthesis of filters for specified axial irradiance by use of phase–space tomography
2001
A procedure for designing pupil filters for applications where specified axial responses are required is developed. The method is based on the mathematical relationship between the axial impulse response of a system and the Wigner distribution function (WDF) associated to its pupil function. The desired axial irradiance, which can also have a predefined behavior depending on spherical aberration, is used to obtain this WDF by tomographic reconstruction. The synthetic pupil is retrieved from this distribution.
White-light implementation of the Wigner-distribution function with an achromatic processor.
2010
A temporally incoherent optical processor that combines diffractive and refractive components is proposed for performing two different operations simultaneously: an achromatic image along an axis and an achromatic one-dimensional Fourier transformation along the orthogonal axis. These properties are properly employed to achieve the achromatic white-light display of the Wigner-distribution function associated with a one-dimensional real signal, with high redundancy and variable scale.
2012
We study the Wigner function for a quantum system with a discrete, infinite dimensional Hilbert space, such as a spinless particle moving on a one dimensional infinite lattice. We discuss the peculiarities of this scenario and of the associated phase space construction, propose a meaningful definition of the Wigner function in this case, and characterize the set of pure states for which it is non-negative. We propose a measure of non-classicality for states in this system which is consistent with the continuum limit. The prescriptions introduced here are illustrated by applying them to localized and Gaussian states, and to their superpositions.
Zvaigžņotā Debess: 2011/12, Ziema (214)
2011
Saturs: Gamma staru astronomijas problēmas ; Apollo-14 Mēness ekspedīcija ; A.Laure. Protoplanetāro miglāju stadija zvaigžņu evolūcijā ; A.A. Jaunumi īsumā: Oglekļa zvaigzne un rentgenstaru avots ; A.Alksnis. Heršels ielūkojas Miras galvā ; D.Docenko. Jauns dziļš debess apskats WiggleZ ir pabeigts: gaidām rezultātus ; A.A. Jaunumi īsumā: Pundurplanēta Erīda ir precīzi izmērīta. Atvērto durvju dienā Garhingā... ; M.Gertāns. Iepazīstot Kenedija kosmosa centru un atvadoties no Space Shuttle ; J.Dambītis. Ievērojams Latvijas matemātiķis – docents Nikolajs Brāzma (1913-1966) ; J.Jansons. Fiziķu centieni 1950.-1960. gados atgriezt fundamentālo zinātni Universitātē ; V.Fļorovs, A.Cēbers, D.Bočarov…
Resonances for nonanalytic potentials
2009
We consider semiclassical Schr"odinger operators on $R^n$, with $C^infty$ potentials decaying polynomially at infinity. The usual theories of resonances do not apply in such a non-analytic framework. Here, under some additional conditions, we show that resonances are invariantly defined up to any power of their imaginary part. The theory is based on resolvent estimates for families of approximating distorted operators with potentials that are holomorphic in narrow complex sectors around $R^n$.
Diffractive dijet production and Wigner distributions from the color glass condensate
2019
Experimental processes that are sensitive to parton Wigner distributions provide a powerful tool to advance our understanding of proton structure. In this work, we compute gluon Wigner and Husimi distributions of protons within the Color Glass Condensate framework, which includes a spatially dependent McLerran-Venugopalan initial configuration and the explicit numerical solution of the JIMWLK equations. We determine the leading anisotropy of the Wigner and Husimi distributions as a function of the angle between impact parameter and transverse momentum. We study experimental signatures of these angular correlations at a proposed Electron Ion Collider by computing coherent diffractive dijet p…
Light-front transverse charge densities
2010
We discuss the recent interpretation of quark-distribution functions in the plane transverse to the light-cone direction. Such a mapping is model independent and allows one to build up multidimensional pictures of the hadron and to develop a semi-classical interpretation of the quark dynamics. We comment briefly the results obtained from the form factors of the nucleon. We show that a generalization to a target with arbitrary spin leads to a set of preferred values for the electromagnetic coupling characterizing structureless particles. Finally, we present the Wigner distribution for an unpolarized quark in an unpolarized proton and we propose an interpretation of the observed distortion as…
Production of exotic tetraquarks QQq¯q¯ in heavy-ion collisions at the LHC
2019
We investigate the production of exotic tetraquarks, $QQ\overline{q}\overline{q}\ensuremath{\equiv}{T}_{QQ}$ ($Q=c$ or $b$ and $q=u$ or $d$), in relativistic heavy-ion collisions using the quark coalescence model. The ${T}_{QQ}$ yield is given by the overlap of the density matrix of the constituents in the emission source with the Wigner function of the produced tetraquark. The tetraquark wave function is obtained from exact solutions of the four-body problem using realistic constituent models. The production yields are typically one order of magnitude smaller than previous estimations based on simplified wave functions for the tetraquarks. We also evaluate the consequences of the partial r…
Quantum light depolarization: the phase-space perspective
2008
Quantum light depolarization is handled through a master equation obtained by coupling dispersively the field to a randomly distributed atomic reservoir. This master equation is solved by transforming it into a quasiprobability distribution in phase space and the quasiclassical limit is investigated.
Reliģiski-filozofiski raksti, 20
2016
Katrā no rakstiem, kas publicēti šajos "Reliģiski-filozofiskos rakstos", šķiet, iespējams saskatīsim gan pagātnes sprostā patvērušos brīvību ar tās apreibinošajās ilūzijām par neatkarību ārpus sprosta, gan nojaust neatrisināmo un reizēm iznīcinošo dilemmu starp gara un reālo pasauli, starp spēli un brīdi, kad spēle beidzas. Piemēram, par pagātnē iesprostotas virtuālās pasaules konstruēšanu, kuras brīvībā izlaušanās mērāma iznīcinātu dzīvību tūkstošos, mums stāsta Māris Kūlis savā rakstā “Islāma valsts propaganda digitālajā laikmetā”. Uzsverot, ka Islāma valsts īstenotais militārais un ārkārtīgi agresīvais džihāds ar vēl nepieredzētām sekmēm ir izveidojis sinkrētisku reliģiskās degsmes un mū…