930 research outputs found

    Localization of resonance eigenfunctions on quantum repellers

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    We introduce a new phase space representation for open quantum systems. This is a very powerful tool to help advance in the study of the morphology of their eigenstates. We apply it to two different versions of a paradigmatic model, the baker map. This allows to show that the long-lived resonances are strongly scarred along the shortest periodic orbits that belong to the classical repeller. Moreover, the shape of the short-lived eigenstates is also analyzed. Finally, we apply an antiunitary symmetry measure to the resonances that permits to quantify their localization on the repeller.Comment: 4 pages, 4 figure

    Transient features of quantum open maps

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    We study families of open chaotic maps that classically share the same asymptotic properties -- forward and backwards trapped sets, repeller dimensions, escape rate -- but differ in their short time behavior. When these maps are quantized we find that the fine details of the distribution of resonances and the corresponding eigenfunctions are sensitive to the initial shape and size of the openings. We study phase space localization of the resonances with respect to the repeller and find strong delocalization effects when the area of the openings is smaller than \hbar.Comment: 7 pages, 7 figure

    Behavior of the current in the asymmetric quantum multibaker map

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    Recently, a new mechanism leading to purely quantum directed transport in the asymmetric multibaker map has been presented. Here, we show a comprehensive characterization of the finite asymptotic current behavior with respect to the hh value, the shape of the initial conditions, and the features of the spectrum. We have considered different degrees of asymmetry in these studies and we have also analyzed the classical and quantum phase space distributions for short times in order to understand the mechanisms behind the generation of the directed current.Comment: 8 pages, 8 figure

    Peri-implant diseases and metabolic syndrome components: a systematic review

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    OBJECTIVE: Metabolic syndrome (MetS) is defined as a spectrum of conditions associated with an increased risk of developing CVD and type 2 diabetes. MetS include: hyperglycemia, hypertension, visceral obesity, dyslipidemia with elevated values of triglycerides (TG) and low levels of HDL. The aim of this review is to provide current knowledge of the relationship between MetS, its components and peri-implant diseases. MATERIALS AND METHODS: An electronic literature search was conducted in the English language in several databases. The Newcastle-Ottawa Scale was used for quality assessment of cohort and cross-sectional studies; while systematic reviews were evaluated through AMSTAR; results were reported according to the PRISMA Statement. RESULTS: A total of 272 records were identified through database searching, six studies were included for qualitative analysis. No study directly related to MetS was found, there was inconsistent and controversial evidence regarding association with cardiovascular disease. A higher risk of peri-implantitis was detected in people with hyperglycemia. CONCLUSIONS: Future research should be orientated in assessing the risk of peri-implant diseases, evaluating patient's therapeutic response, analyzing directionality of the relationship between MetS, its components and biologic implant complications. Few studies have investigated the possible relationship between systemic conditions and peri-implant diseases. The aim of this review is to present, in a systematic manner, current evidence and knowledge regarding possible association between cardiovascular disease and implant biologic complications. Out of the one-hundred-eighty-nine studies screened, just five studies were selected for qualitative analysis: three cohort studies (one prospective and two retrospectives) and two cross-sectional studies. According to their results, there is inconsistent and controversial evidence regarding association of cardiovascular disease and implant biologic complications. Future research should be orientated in conducting longitudinal studies, evaluating patients affected by cardiovascular disease rehabilitated with dental implants

    Regular and chaotic regimes in coupled-channel calculations of nuclear scattering processes

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    The presence of regular and chaotic regimes in nuclear scattering processes has so far been established in the context of simple, schematic reaction models. It has been argued that traces of the underlying classical organization of phase space should also be present in complex quantal calculations performed with state-of-the-art coupled-channel codes. In this paper we show that this is indeed the case and develop concrete guidelines to infer - relying exclusively on features of the quantal results - the regular or chaotic character of the motion
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