696 research outputs found

    Metal-dielectric superlenses for ultraviolet and visible light

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    A Happy Marriage: The Stop and Affricate Inventory of the Mixed Language Light Warlpiri (Australia)

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    This paper presents a first acoustic analysis of the stops and affricates of the mixed language Light Warlpiri (Australia). The results suggest that the Light Warlpiri phonological inventory consists of a voiced and voiceless series of stops and affricates, differentiated by Voice Onset Time (VOT) wordinitially and by Constriction Duration (CD) medially, by incorporating English-like VOT differentiation and Constriction duration differences found in Kriol and also in a number of traditional Indigenous Australian languages. Word-initially, stops from Warlpiri words pattern with English/Kriol voiced stops; medially with the ‘long’ stops in Kriol, /c/ being the exception in patterning with short /ʤ/, rather than the voiceless /ʧ/. This inventory allows speakers of Light Warlpiri to maintain sufficient phonemic contrasts to accommodate vocabulary items in Light Warlpiri sourced from English/Kriol as well as Warlpiri, the Indigenous Australian language that they also speak

    When more is more : the mixed language Light Warlpiri amalgamates source language phonologies to form a near-maximal inventory

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    This paper presents a combined analysis of the perception and production study of the mixed language Light Warlpiri (Australia), which systematically combines elements of Warlpiri, Kriol and English. The perception and production results suggest that the Light Warlpiri phonological inventory consists of a voiced and voiceless series of stops and affricates, differentiated by Voice Onset Time (VOT) word-initially and by Constriction Duration (CD) medially, by incorporating English-like VOT differentiation and Constriction duration differences found in Kriol and also in a number of traditional Indigenous Australian languages. The results also show that Light Warlpiri speakers perceptually differentiate stops and fricatives at the same POA, but that voicing distinctions in fricatives are more difficult to discriminate than voicing distinctions in stops. The large phonological inventory of Light Warlpiri combines most features of the source languages, allowing speakers of Light Warlpiri to maintain sufficient phonemic contrasts to accommodate vocabulary items in Light Warlpiri sourced from English/Kriol as well as Warlpiri

    The presence of bacteria varies between colorectal adenocarcinomas, precursor lesions and non-malignant tissue

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    Tissue samples used for 16S rRNA gene sequencing. Quantification cycles obtained using qPCR and clinical information for each clinical sample investigated using Illumina sequencing of the V4 region of the 16S rRNA gene. (XLSX 31 kb

    Electron-phonon decoupling due to strong light-matter interactions

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    Phonon interactions in solid-state photonics systems cause intrinsic quantum decoherence and often present the limiting factor in emerging quantum technology. Due to recent developments in nanophotonics, exciton-cavity structures with very strong light-matter coupling rates can be fabricated. We show that in such structures, a new regime emerges, where the decoherence is completely suppressed due to decoupling of the dominant phonon process. Using a numerically exact tensor network approach, we perform calculations in this non-perturbative, non-Markovian dynamical regime. Here, we identify a strategy for reaching near-unity photon indistinguishability and also discover an interesting phonon-dressing of the exciton-cavity polaritons in the high-Q regime, leading to multiple phonon sidebands when the light-matter interaction is sufficiently strong.Comment: Accepted for publication in Physical Review

    Non-Markovian perturbation theories for phonon effects in strong-coupling cavity quantum electrodynamics

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    Phonon interactions are inevitable in cavity quantum electrodynamical systems based on solid-state emitters or fluorescent molecules, where vibrations of the lattice or chemical bonds couple to the electronic degrees of freedom. Due to the non-Markovian response of the vibrational environment, it remains a significant theoretical challenge to describe such effects in a computationally efficient manner. This is particularly pronounced when the emitter-cavity coupling is comparable to or larger than the typical phonon energy range, and polariton formation coincides with vibrational dressing of the optical transitions. In this Article, we consider four non-Markovian perturbative master equation approaches to describe such dynamics over a broad range of light-matter coupling strengths and compare them to numerically exact reference calculations using a tensor network. The master equations are derived using different basis transformations and a perturbative expansion in the new basis is subsequently introduced and analyzed. We find that two approaches are particularly successful and robust. The first of these is suggested and developed in this Article and is based on a vibrational dressing of the exciton-cavity polaritons. This enables the description of distinct phonon-polariton sidebands that appear when the polariton splitting exceeds the typical phonon frequency scale in the environment. The second approach is based on a variationally optimized polaronic vibrational dressing of the electronic state. Both of these approaches demonstrate good qualitative and quantitative agreement with reference calculations of the emission spectrum and are numerically robust, even at elevated temperatures, where the thermal phonon population is significant.Comment: 17 pages, 10 figure

    A definition of normovolaemia and consequences for cardiovascular control during orthostatic and environmental stress

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    The Frank–Starling mechanism describes the relationship between stroke volume and preload to the heart, or the volume of blood that is available to the heart—the central blood volume. Understanding the role of the central blood volume for cardiovascular control has been complicated by the fact that a given central blood volume may be associated with markedly different central vascular pressures. The central blood volume varies with posture and, consequently, stroke volume and cardiac output (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}Q˙ \dot{Q} \end{document}) are affected, but with the increased central blood volume during head-down tilt, stroke volume and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}Q˙ \dot{Q} \end{document} do not increase further indicating that in the supine resting position the heart operates on the plateau of the Frank–Starling curve which, therefore, may be taken as a functional definition of normovolaemia. Since the capacity of the vascular system surpasses the blood volume, orthostatic and environmental stress including bed rest/microgravity, exercise and training, thermal loading, illness, and trauma/haemorrhage is likely to restrict venous return and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}Q˙ \dot{Q} \end{document}. Consequently the cardiovascular responses are determined primarily by their effect on the central blood volume. Thus during environmental stress, flow redistribution becomes dependent on sympathetic activation affecting not only skin and splanchnic blood flow, but also flow to skeletal muscles and the brain. This review addresses the hypothesis that deviations from normovolaemia significantly influence these cardiovascular responses

    A stochastic approach to the quantum noise of a single-emitter nanolaser

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    It is shown that the intensity quantum noise of a single-emitter nanolaser can be accurately computed by adopting a stochastic interpretation of the standard rate equation model under the only assumption that the emitter excitation and photon number are stochastic variables with integer values. This extends the validity of rate equations beyond the mean-field limit and avoids using the standard Langevin approach, which is shown to fail for few emitters. The model is validated by comparison to full quantum simulations of the relative intensity noise and second-order intensity correlation function, g(2)({\tau} ). Surprisingly, even when the full quantum model displays vacuum Rabi oscillations, which are not accounted for by rate equations, the intensity quantum noise is correctly predicted by the stochastic approach. Adopting a simple discretization of the emitter and photon populations, thus, goes a long way in describing quantum noise in lasers. Besides providing a versatile and easy-to-use tool for modeling a new generation of nanolasers with many possible applications, these results provide insight into the fundamental nature of quantum noise in lasers.Comment: Revised and resubmitted for revie
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