966 resultados para Transition moments, Coupled-Cluster theory, excited states, triplet, excimer


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Mode of access: Internet.

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Thesis (Ph.D.)--University of Washington, 2016-06

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We propose an approach to optical quantum computation in which a deterministic entangling quantum gate may be performed using, on average, a few hundred coherently interacting optical elements (beam splitters, phase shifters, single photon sources, and photodetectors with feedforward). This scheme combines ideas from the optical quantum computing proposal of Knill, Laflamme, and Milburn [Nature (London) 409, 46 (2001)], and the abstract cluster-state model of quantum computation proposed by Raussendorf and Briegel [Phys. Rev. Lett. 86, 5188 (2001)].

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In this work we investigate the energy gap between the ground state and the first excited state in a model of two single-mode Bose-Einstein condensates coupled via Josephson tunnelling. The ene:rgy gap is never zero when the tunnelling interaction is non-zero. The gap exhibits no local minimum below a threshold coupling which separates a delocalized phase from a self-trapping phase that occurs in the absence of the external potential. Above this threshold point one minimum occurs close to the Josephson regime, and a set of minima and maxima appear in the Fock regime. Expressions for the position of these minima and maxima are obtained. The connection between these minima and maxima and the dynamics for the expectation value of the relative number of particles is analysed in detail. We find that the dynamics of the system changes as the coupling crosses these points.

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A self-consistent theory is derived to describe the BCS-Bose-Einstein-condensate crossover for a strongly interacting Fermi gas with a Feshbach resonance. In the theory the fluctuation of the dressed molecules, consisting of both preformed Cooper pairs and bare Feshbach molecules, has been included within a self-consistent T-matrix approximation, beyond the Nozieres and Schmitt-Rink strategy considered by Ohashi and Griffin. The resulting self-consistent equations are solved numerically to investigate the normal-state properties of the crossover at various resonance widths. It is found that the superfluid transition temperature T-c increases monotonically at all widths as the effective interaction between atoms becomes more attractive. Furthermore, a residue factor Z(m) of the molecule's Green function and a complex effective mass have been determined to characterize the fraction and lifetime of Feshbach molecules at T-c. Our many-body calculations of Z(m) agree qualitatively well with recent measurments of the gas of Li-6 atoms near the broad resonance at 834 G. The crossover from narrow to broad resonances has also been studied.

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The red fluorescent protein Rtms5H146S displays a transition from blue (absorbance λmax 590 nm) to yellow (absorbance λmax not, vert, similar453 nm) upon titration to low pH. The pKa of the reaction depends on the concentration of halide, offering promise for new expressible halide sensors. The protonation state involved in the low pH form of the chromophore remains, however, ambiguous. We report calculated excitation energies of different protonation states of an RFP chromophore model. These suggest that the relevant titration site is the phenoxy moiety of the chromophore, and the relevant base and conjugate acid are anionic and neutral chromophore species, respectively.

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We describe a generalization of the cluster-state model of quantum computation to continuous-variable systems, along with a proposal for an optical implementation using squeezed-light sources, linear optics, and homodyne detection. For universal quantum computation, a nonlinear element is required. This can be satisfied by adding to the toolbox any single-mode non-Gaussian measurement, while the initial cluster state itself remains Gaussian. Homodyne detection alone suffices to perform an arbitrary multimode Gaussian transformation via the cluster state. We also propose an experiment to demonstrate cluster-based error reduction when implementing Gaussian operations.

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We analyze the stochastic creation of a single bound state (BS) in a random potential with a compact support. We study both the Hermitian Schrödinger equation and non-Hermitian Zakharov-Shabat systems. These problems are of special interest in the inverse scattering method for Korteveg–de-Vries and the nonlinear Schrödinger equations since soliton solutions of these two equations correspond to the BSs of the two aforementioned linear eigenvalue problems. Analytical expressions for the average width of the potential required for the creation of the first BS are given in the approximation of delta-correlated Gaussian potential and additionally different scenarios of eigenvalue creation are discussed for the non-Hermitian case.

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Drawing on the existing body of literature that deals with national preference formation and building on the role played by vulnerability and deficits in shaping policy choices at the European level, this article provides a synthetic framework to explain the stances of the Older Member States (OMS) and New Member States (NMS). We subsequently apply the model to NMS, focusing largely, although not exclusively, on Poland. We argue that although many of the policy preferences can be explained by the framework, the size of states, especially with regard to ambition and capacity, and the nature of the country's post-communist transition appear significant for the NMS and need to be incorporated into future theory-building. We conclude by highlighting areas in need of further empirical research. © 2009 Blackwell Publishing Ltd.

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Fifteen years ago, twenty-seven countries in Europe and Central Asia embarked on their economic transition paths. For some, the outcome was a considerable success. Several others are still struggling to shed the inheritance of the past and to correct more recent policy mistakes. Why were post-Communist recessions so long in some countries and growth disappointing? Why was fiscal performance so different? Was democracy a factor, which facilitated reforms or rather slowed them down? This book discusses these questions in the context of new empirical evidence, including a critical examination of the main themes in the economics of transition.

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Transition P Systems are a parallel and distributed computational model based on the notion of the cellular membrane structure. Each membrane determines a region that encloses a multiset of objects and evolution rules. Transition P Systems evolve through transitions between two consecutive configurations that are determined by the membrane structure and multisets present inside membranes. Moreover, transitions between two consecutive configurations are provided by an exhaustive non-deterministic and parallel application of evolution rules. But, to establish the rules to be applied, it is required the previous calculation of useful, applicable and active rules. Hence, computation of useful evolution rules is critical for the whole evolution process efficiency, because it is performed in parallel inside each membrane in every evolution step. This work defines usefulness states through an exhaustive analysis of the P system for every membrane and for every possible configuration of the membrane structure during the computation. Moreover, this analysis can be done in a static way; therefore membranes only have to check their usefulness states to obtain their set of useful rules during execution.

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A főáramlat közgazdászai elismerik, hogy a szocialista rendszert a krónikus hiány jellemezte, de úgy vélik, hogy a kapitalista rendszerben - kisebb vagy nagyobb ingadozások közepette - piaci egyensúly uralkodik. Ezzel szemben a tanulmány két piaci állapotot állít egymással szembe. Az egyikben dominálnak a túlkeresleti jelenségek, bár előfordulnak túlkínálati jelenségek is, ezt nevezi a szerző hiánygazdaságnak. A másikban dominálnak a túlkínálati jelenségek, bár előfordulnak túlkeresleti jelenségek is, amit a szerző többletgazdaságnak nevez. A tanulmány II. része összefoglalja a tanulmány fő állításait. Ezek szerint a szocialista rendszer veleszületett immanens tulajdonsága a hiánygazdaság, míg a kapitalista rendszer veleszületett immanens tulajdonsága a többletgazdaság létrehozása és állandó reprodukciója. Állami beavatkozások erősíthetik vagy gyengíthetik ezeket a genetikus tulajdonságokat, de nem szüntethetik meg. A tanulmány áttekinti a többletgazdaság kedvező és kedvezőtlen hatásait. A kedvező hatások között különleges nyomatékkal emeli ki, hogy a többlet (elsősorban többletkapacitások) nélkül nem alakulhat ki a termelők, illetve az eladók rivalizálása, ami az innovációs folyamat legfontosabb hajtóereje. A többletgazdaság általános esetének vizsgálata után különböző speciális esetekkel foglalkozik a tanulmány: a gazdaság konjunkturális hullámzásával, a hadigazdasággal, a modern kapitalizmusban mutatkozó történelmi léptékű változásokkal, valamint a szocialista rendszeren belül megjelent piacorientált reformokkal és a posztszocialista átmenettel. ____ Mainstream economists recognize that the socialist system was marked by chronic shortage, but they consider that the capitalist system exhibits market equilibrium, give or take some greater or lesser fluctuations. This study, however, contrasts two market states. One is dominated by phenomena of excess demand, though instances of excess supply appear as well; this the author calls a shortage economy. The other is dominated by phenomena of excess supply, though instances of excess demand appear as well; this the author terms a surplus economy. Part II of the study starts by summing up its main propositions. Just as the shortage economy is an intrinsic, immanent trait of the socialist system, so the creation and continual reproduction of the surplus economy is an intrinsic, immanent trait of the capitalist system. Such genetic traits may be strengthened or weakened by state intervention, but not eliminated by it. The study reviews the favourable and detrimental effects of the surplus economy. Of the favourable effects, it is emphasized that without surplus there cannot develop among producers or sellers the rivalry that provides the main impetus for the innovation process. Having examined the general case of the surplus economy, the study turns to various special cases: to the trade-cycle fluctuations of the economy, the war economy, the historic changes appearing in modern capitalism, the market-oriented reforms that appear within the socialist system, and the post-socialist transition.