A single trapped ion in a finite range trap

This paper presents a method to describe dynamics of an ion confined in a realistic finite range trap. We model this realistic potential with a solvable one and we obtain dynamical variables (raising and lowering operators) of this potential. We consider coherent interaction of this confined ion in a finite range trap and we show that its center-of-mass motion steady state is a special kind of nonlinear coherent states. Physical properties of this state and their dependence on the finite range of potential are studied

A single trapped ion in a finite range trap

This paper presents a method to describe dynamics of an ion confined in a realistic finite range trap. We model this realistic potential with a solvable one and we obtain dynamical variables (raising and lowering operators) of this potential. We consider coherent interaction of this confined ion in a finite range trap and we show that its center-of-mass motion steady state is a special kind of nonlinear coherent states. Physical properties of this state and their dependence on the finite range of potential are studied

Parametric oscillator in a Kerr medium: evolution of coherent states

We study the temporal evolution of a coherent state under the action of a parametric oscillator and a nonlinear Kerr-like medium. We make use of the interaction picture representation and use an exact time evolution operator for the time independent part of the Hamiltonian. We approximate the interaction picture Hamiltonian in such a way as to make it a member of a Lie algebra. The corresponding time evolution operator behaves like a squeezing operator due to the temporal dependence of the oscillator's frequency. We analyze the probability amplitude and the auto correlation function for different Hamiltonian parameters and we find a very good agreement between our approximate results and converged numerical calculations.Comment: 11 pages, 3 figure

Deformation Quantization: Quantum Mechanics Lives and Works in Phase-Space

Wigner's quasi-probability distribution function in phase-space is a special (Weyl) representation of the density matrix. It has been useful in describing quantum transport in quantum optics; nuclear physics; decoherence (eg, quantum computing); quantum chaos; "Welcher Weg" discussions; semiclassical limits. It is also of importance in signal processing. Nevertheless, a remarkable aspect of its internal logic, pioneered by Moyal, has only emerged in the last quarter-century: It furnishes a third, alternative, formulation of Quantum Mechanics, independent of the conventional Hilbert Space, or Path Integral formulations. In this logically complete and self-standing formulation, one need not choose sides--coordinate or momentum space. It works in full phase-space, accommodating the uncertainty principle. This is an introductory overview of the formulation with simple illustrations.Comment: LaTeX, 22 pages, 2 figure

Classical and quantum shortcuts to adiabaticity for scale-invariant driving

A shortcut to adiabaticity is a driving protocol that reproduces in a short time the same final state that would result from an adiabatic, infinitely slow process. A powerful technique to engineer such shortcuts relies on the use of auxiliary counterdiabatic fields. Determining the explicit form of the required fields has generally proven to be complicated. We present explicit counterdiabatic driving protocols for scale-invariant dynamical processes, which describe for instance expansion and transport. To this end, we use the formalism of generating functions, and unify previous approaches independently developed in classical and quantum studies. The resulting framework is applied to the design of shortcuts to adiabaticity for a large class of classical and quantum, single-particle, non-linear, and many-body systems.Comment: 17 pages, 5 figure

Zur Textsemiotik des Titels

enthält: Zur Geschichte des Buchtitels, Das Ding mit dem Titel oder Tascosa-Bill jagt die Hausweber-Evi; Semiotische Funktionen des Titels; Texte, Themen, Titel. Die Überschrift im Rahmen der Textsemantik; Titel und Textverarbeitungen. Beiträge zur empirischen Textforschun

Thermoelectric properties of indium doped PbTe_(1-y)Se_y alloys

Lead telluride and its alloys are well known for their thermoelectric applications. Here, a systematic study of PbTe_(1-y)Se_y alloys doped with indium has been done. The powder X-Ray diffraction combined with Rietveld analysis confirmed the polycrystalline single phase nature of the samples, while microstructural analysis with scanning electron microscope results showed densification of samples and presence of micrometer sized particles. The temperature dependent transport properties showed that in these alloys, indium neither pinned the Fermi level as it does in PbTe, nor acted as a resonant dopant as in SnTe. At high temperatures, bipolar effect was observed which restricted the zT to 0.66 at 800 K for the sample with 30% Se content

L’État-providence soutient qui et comment? Le logement des ménages à revenu modeste dans trois provinces canadiennes, 1975-2015

Bien qu’elles soient peu étudiées, les politiques provinciales de logement ont subi plusieurs changements fondamentaux depuis l’époque des Trente Glorieuses. Ces changements portent sur qui reçoit l’aide gouvernementale et comment cette aide est dépensée. Toutes ces modifications soulèvent des questions cruciales pour notre compréhension de l’État-providence. La thèse examine la similarité des politiques de logement destinées aux ménages à revenu modeste en Colombie-Britannique, en Alberta et au Québec. Cette ressemblance est particulièrement intéressante après le désengagement du gouvernement fédéral au milieu des années 1990. Elle s’articule autour de trois changements fondamentaux : 1) l’aide est surtout canalisée vers les ménages en situation vulnérable ; 2) les nouvelles unités de logement social/abordable se réalisent essentiellement à travers les organismes sans but lucratif du tiers secteur et non plus sur le modèle des habitations à loyer modique (HLM) appartenant à l’État ; 3) les mesures axées sur le marché locatif privé (allocation-logement et supplément au loyer) sont beaucoup utilisées. Comment et pourquoi les provinces ont-elles décidé de formuler des politiques de logement semblables ? Ces trois provinces sont pourtant connues pour avoir des approches distinctes en matière de politiques sociales. À partir du matériel obtenu dans les archives et à travers des entrevues avec des personnes clés, notre analyse démontre que les trois changements fondamentaux dans les provinces sont le résultat de l’interaction de deux processus. Le plus important est le processus de puzzling et ses deux mécanismes d’apprentissage (social et instrumental) qui permettent de comprendre qu’en contexte de resserrement budgétaire, les décideurs aient fait le choix difficile de cibler les personnes plus vulnérables selon le principe d’équité, puis de se détourner du modèle HLM appartenant à l’État pour des raisons d’efficience. Les administrateurs des trois provinces ont davantage financé le logement sans but lucratif possédé par les groupes du tiers secteur et misé sur les instruments axés sur le marché locatif privé pour les avantages économiques et non économiques de ces formules. Cependant, le processus de puzzling rencontre le processus de dépendance au sentier et ses deux mécanismes (rétroaction des politiques publiques et rendements croissants) dans la prise de décision. Ces deux mécanismes liés à la dépendance au sentier aident à comprendre pourquoi les subventions aux groupes du tiers secteur ainsi que le recours aux allocations-logement et suppléments au loyer, qui avaient débuté avant le repli fédéral, se sont poursuivis. Les changements fondamentaux à propos des instruments utilisés s’inscrivent donc dans une certaine continuité. Outre notre contribution empirique découlant de l’étude de la politique de logement dans trois grandes provinces des années 1970 aux années 2010, la thèse développe un cadre analytique autour de l’apprentissage et de la recherche permanente d’une meilleure utilisation des ressources limitées. Ce cadre d’analyse mécanistique permet de mieux comprendre la prise de décision des gouvernants, entre les forces d’innovation et de continuité, avec l’objectif de maximiser le bien-être au moindre coût possible pour l’État. Basé sur les prémisses de l’économie du bien-être, ce cadre analytique s’appuie sur l’évaluation coûts-bénéfices traditionnelle en lien avec l’efficience, en intégrant l’aspect normatif de l’équité.Although understudied, low-income housing policy in Canadian provinces have experienced fundamental shifts since the welfare state’s expansion during the post-war era. These shifts relate to who benefits from public monies and how these are spent. Such changes raise important questions for our understanding of the welfare state. This dissertation examines the policy similarity of low-income housing policy in British Columbia, Alberta and Quebec. The resemblance is particularly interesting after the federal government’s disengagement from the low-income housing domain in the mid-1990s. The policy similarity focuses around three fundamental shifts: 1) targeting of vulnerable citizens; 2) construction of new social/affordable housing units through third sector providers rather than government-owned public housing projects; 3) stronger use of private market instruments (housing allowance and rent supplement). How and why did the provinces decide to design similar housing policies? Yet the three provinces are known to have different approaches with regard to social policy. Starting with empirical material collected in archives and through interviews with policy elites, the analysis demonstrates that the three fundamental shifts in each province result from the interaction of two processes. The most important one is the puzzling process with its two learning mechanisms (social and instrumental). They can help us to understand that in a context of cost-containment, decision-makers have made the difficult choice to target the most vulnerable citizens following an equity principle, and to move away from the traditional public housing model for efficiency reasons. Public administrators in the three provinces have mostly financed non-profit housing owned by non-profit groups in the third sector and supported private market instruments. However, the puzzling process meets with the path dependence process and its two mechanisms (policy feedback and increasing returns) in the decision-making phase. Both of these mechanisms are useful to understand why subsidies to third sector groups and the use of housing allowances as well as rent supplements, which have started before the federal withdrawal, were pursued. Therefore the fundamental shifts with regard to policy instruments exhibit a certain form of continuity. In addition to the empirical contribution resulting from the study of three major provinces from the 1970s to the 2010s, the thesis develops an analytical framework around policy learning and the permanent search for the best use of scarce resources. This mechanismic framework furthers our understanding of government decision-making, between innovation and continuity forces, with the objective to maximize social welfare at the lowest possible cost for government. Based on welfare economics premises, this analytical framework relies on traditional cost-benefit evaluation seeking efficiency, but also integrates the normative aspect of equity