18,964 research outputs found

    Estado Confusional Agudo apĂłs Corticoterapia Inalada

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    Background: The connection between corticotherapy and neuropsychiatric symptoms is widely known, being one of the first questions we need to assess when presenting with first episode psychiatric symptoms or confusional state. Aims: To date, data on cases related to inhaled corticotherapy and neuropsychiatric effects is scarce. In this paper we describe a rare case in a young woman. Methods: The clinical case presented led us to try to understand the data published on the subject in order to discuss it in greater length. Results and Conclusions: We present and discuss a 27-year-old patient’s case, with no previous psychiatric disease, who was admitted to our Psychiatric ward after the onset of severe acute behavioural disturbance characterized by aggressiveness, visual and auditory hallucinatory activity, misidentification and altered conscience status. It was later found that seven days earlier she had been prescribed inhaled corticotherapy for a minor respiratory infection. A few days after corticotherapy withdrawal, the clinical symptoms improved significantly.info:eu-repo/semantics/publishedVersio

    Nuclear State Preparation via Landau-Zener-Stueckelberg transitions in Double Quantum Dots

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    We theoretically model a nuclear-state preparation scheme that increases the coherence time of a two-spin qubit in a double quantum dot. The two-electron system is tuned repeatedly across a singlet-triplet level-anticrossing with alternating slow and rapid sweeps of an external bias voltage. Using a Landau-Zener-Stueckelberg model, we find that in addition to a small nuclear polarization that weakly affects the electron spin coherence, the slow sweeps are only partially adiabatic and lead to a weak nuclear spin measurement and a nuclear-state narrowing which prolongs the electron spin coherence. This resolves some open problems brought up by a recent experiment [D. J. Reilly et al., Science 321, 817 (2008).]. Based on our description of the weak measurement, we simulate a system with up to n=200 nuclear spins per dot. Scaling in n indicates a stronger effect for larger n.Comment: 4.1 pages, 2 figure

    Dynamical properties across a quantum phase transition in the Lipkin-Meshkov-Glick model

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    It is of high interest, in the context of Adiabatic Quantum Computation, to better understand the complex dynamics of a quantum system subject to a time-dependent Hamiltonian, when driven across a quantum phase transition. We present here such a study in the Lipkin-Meshkov-Glick (LMG) model with one variable parameter. We first display numerical results on the dynamical evolution across the LMG quantum phase transition, which clearly shows a pronounced effect of the spectral avoided level crossings. We then derive a phenomenological (classical) transition model, which already shows some closeness to the numerical results. Finally, we show how a simplified quantum transition model can be built which strongly improve the classical approach, and shed light on the physical processes involved in the whole LMG quantum evolution. From our results, we argue that the commonly used description in term of Landau-Zener transitions is not appropriate for our model.Comment: 7 pages, 5 figures; corrected reference

    General scalar products in the arbitrary six-vertex model

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    In this work we use the algebraic Bethe ansatz to derive the general scalar product in the six-vertex model for generic Boltzmann weights. We performed this calculation using only the unitarity property, the Yang-Baxter algebra and the Yang-Baxter equation. We have derived a recurrence relation for the scalar product. The solution of this relation was written in terms of the domain wall partition functions. By its turn, these partition functions were also obtained for generic Boltzmann weights, which provided us with an explicit expression for the general scalar product.Comment: 24 page

    Small Deviations from Gaussianity and The Galaxy Cluster Abundance Evolution

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    We raise the hypothesis that the density fluctuations field which originates the growth of large scale structures is a combination of two or more distributions. By applying the statistical analysis of finite mixture distributions to a specific combination of Gaussian plus non-Gaussian random fields, we studied the case where just a small departure from Gaussianity is allowed. Our results suggest that even a very small level of non-Gaussianity may introduce significant changes in the cluster abundance evolution rate.Comment: 10 pages with 2 figures, accepted for publication in Ap
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