2,229 research outputs found

    An exact master equation for the system-reservoir dynamics under the strong coupling regime and non-Markovian dynamics

    Get PDF
    In this paper we present a method to derive an exact master equation for a bosonic system coupled to a set of other bosonic systems, which plays the role of the reservoir, under the strong coupling regime, i.e., without resorting to either the rotating-wave or secular approximations. Working with phase-space distribution functions, we verify that the dynamics are separated in the evolution of its center, which follows classical mechanics, and its shape, which becomes distorted. This is the generalization of a result by Glauber, who stated that coherent states remain coherent under certain circumstances, specifically when the rotating-wave approximation and a zero-temperature reservoir are used. We show that the counter-rotating terms generate fluctuations that distort the vacuum state, much the same as thermal fluctuations.Finally, we discuss conditions for non-Markovian dynamics

    Teleportation of a Zero-and One-photon Running Wave State by Projection Synthesis

    Full text link
    We show how to teleport a running wave superposition of zero- and one-photon field state through the projection synthesis technique. The fidelity of the scheme is computed taking into account the noise introduced by dissipation and the efficiency of the detectors. These error sources have been introduced through a single general relationship between input and output operators.Comment: 11 pages, 1 figur

    Basis States for Relativistic, Dynamically-Entangled Particles

    Full text link
    In several recent papers on entanglement in relativistic quantum systems and relativistic Bell's inequalities, relativistic Bell-type two-particle states have been constructed in analogy to non-relativistic states. These constructions do not have the form suggested by relativistic invariance of the dynamics. Two relativistic formulations of Bell-type states are shown for massive particles, one using the standard Wigner spin basis and one using the helicity basis. The construction hinges on the use of Clebsch-Gordan coefficients of the Poincar\'e group to reduce the direct product of two unitary irreducible representations (UIRs) into a direct sum of UIRs.Comment: 19 pages, three tables, revte

    Engineering cavity-field states by projection synthesis

    Get PDF
    We propose a reliable scheme for engineering a general cavity-field state. This is different from recently presented strategies,where the cavity is supposed to be initially empty and the field is built up photon by photon through resonant atom-field interactions. Here, a coherent state is previously injected into the cavity. So, the Wigner distribution function of the desired state is constructed from that of the initially coherent state. Such an engineering process is achieved through an adaptation of the recently proposed technique of projection synthesis to cavity QED phenomena.Comment: 5 ps pages plus 3 included figure

    Electromagnetically induced transparency and dynamic Stark effect in coupled quantum resonators

    Full text link
    In this work we reproduce the phenomenology of the electromagnetically induced transparency and dynamic Stark effect in a dissipative system composed by two coupled bosonic fields under linear and nonlinear amplification process. Such a system can be used as a quantum switch in networks of oscillators

    Microwave-assisted synthesis of Pd nanoparticles supported on Fe 3O4, Co3O4, and Ni(OH)2 nanoplates and catalysis application for CO oxidation

    Get PDF
    In this paper, we report a simple, versatile, and rapid method for the synthesis of Pd nanoparticle catalysts supported on Fe3O4, Co3O4, and Ni (OH)2 nanoplates via microwave irradiation. The important advantage of microwave dielectric heating over convective heating is that the reactants can be added at room temperature (or slightly higher temperatures) without the need for high-temperature injection. Furthermore, the method can be used to synthesize metal nanoparticle catalysts supported on metal oxide nanoparticles in one step. We also demonstrate that the catalyst-support interaction plays an important role in the low temperature oxidation of CO. The current results reveal that the Pd/Co3O4 catalyst has particularly high activity for CO oxidation as a result of the strong interaction between the Pd nanoparticles and the Co 3O4 nanoplates. Optimizations of the size, composition, and shape of these catalysts could provide a new family of efficient nanocatalysts for the low temperature oxidation of CO. © 2014 Springer Science+Business Media

    Nonadiabatic geometric phase induced by a counterpart of the Stark shift

    Full text link
    We analyse the geometric phase due to the Stark shift in a system composed of a bosonic field, driven by time-dependent linear amplification, interacting dispersively with a two-level (fermionic) system. We show that a geometric phase factor in the joint state of the system, which depends on the fermionic state (resulting form the Stark shift), is introduced by the amplification process. A clear geometrical interpretation of this phenomenon is provided. We also show how to measure this effect in an interferometric experiment and to generate geometric "Schrodinger cat"-like states. Finally, considering the currently available technology, we discuss a feasible scheme to control and measure such geometric phases in the context of cavity quantum electrodynamics

    Open problems in nuclear density functional theory

    Full text link
    This note describes five subjects of some interest for the density functional theory in nuclear physics. These are, respectively, i) the need for concave functionals, ii) the nature of the Kohn-Sham potential for the radial density theory, iii) a proper implementation of a density functional for an "intrinsic" rotational density, iv) the possible existence of a potential driving the square root of the density, and v) the existence of many models where a density functional can be explicitly constructed.Comment: 10 page

    La tuberculose extra-ganglionnaire de la sphere O.R.L.

    Get PDF
    La tuberculose extra ganglionnaire est une pathologie rare en ORL. Elle pourrait poser des problèmes diagnostiques surtout avec la pathologie tumorale. Nous rapportons 10 cas de localisations extra-ganglionnaires, colligés au service ORL de l\'hôpital Tahar Sfar de Mahdia entre 1988 et 2004. Il s\'agissait de 7 femmes et 3 hommes, âgés entre 19 et 77 ans (moyenne : 39 ans). La maladie a touché le cavum dans 3 cas, les glandes salivaires dans 3 cas, les amygdales palatines dans 2 cas et le larynx chez 2 patients. Le diagnostic était dans tous les cas histo-pathologique. Tous nos patients ont reçu un traitement anti-tuberculeux. L\'évolution était favorable avec un recul moyen de 11 mois. Conclusion : La tuberculose extra-ganglionnaire en ORL pose surtout des problèmes diagnostiques. Son diagnostic est le plus souvent histo-pathologique. Son traitement repose sur la himiothérapie anti-tuberculeuse. Extra-nodal tuberculosis is a rare in ENT practice. We report 10 cases of extra-ganglionic localizations of tuberculosis, treated in ENT department of the Tahar Sfar hospital of Mahdia between 1988 and 2004. They were 7 women and 3 men, aged between 19 and 77 years (average: 39 years) . The disease has touched the nasopharynx in 3 cases, the salivary glands in 3 cases, the tonsils in 2 cases and the larynx in 2 cases. The diagnosis was in all cases histo-pathological. All our patients received an anti-tubercular treatment. The evolution was favorable with 11 months average outcome. Conclusion: Extra-nodal tuberculosis in ENT poses especially diagnostic problems. Its treatment is based on anti-tubercular chemotherapy. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 16 2006: pp. 36-3

    On the (im)possibility of a supersymmetric extension of NGT

    Get PDF
    We investigate the possibility of constructing a locally supersymmetric extension of NGT (Nonsymmetric Gravitation Theory), based on the graded extension of the Poincare group. In the framework of the simple model that we propose, we end up with a no-go result, namely the impossibility of cancelling some linear contribution in the gravitino field. This drawback seems to seriously undermine the construction of a supergravity based on NGT.Comment: 17 pages, Latex,two references added, minor changes for clarity, v3: E-mail changed, v4 : Ref(9) correcte
    corecore