5,055 research outputs found

    Capturing Vacuum Fluctuations and Photon Correlations in Cavity Quantum Electrodynamics with Multi-Trajectory Ehrenfest Dynamics

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    We describe vacuum fluctuations and photon-field correlations in interacting quantum mechanical light-matter systems, by generalizing the application of mixed quantum-classical dynamics techniques. We employ the multi-trajectory implementation of Ehrenfest mean field theory, traditionally developed for electron-nuclear problems, to simulate the spontaneous emission of radiation in a model quantum electrodynamical cavity-bound atomic system. We investigate the performance of this approach in capturing the dynamics of spontaneous emission from the perspective of both the atomic system and the cavity photon field, through a detailed comparison with exact benchmark quantum mechanical observables and correlation functions. By properly accounting for the quantum statistics of the vacuum field, while using mixed quantum-classical (mean field) trajectories to describe the evolution, we identify a surprisingly accurate and promising route towards describing quantum effects in realistic correlated light-matter systems

    Nuclear Mixing Meters for Classical Novae

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    Classical novae are caused by mass transfer episodes from a main sequence star onto a white dwarf via Roche lobe overflow. This material forms an accretion disk around the white dwarf. Ultimately, a fraction of this material spirals in and piles up on the white dwarf surface under electron-degenerate conditions. The subsequently occurring thermonuclear runaway reaches hundreds of megakelvin and explosively ejects matter into the interstellar medium. The exact peak temperature strongly depends on the underlying white dwarf mass, the accreted mass and metallicity, and the initial white dwarf luminosity. Observations of elemental abundance enrichments in these classical nova events imply that the ejected matter consists not only of processed solar material from the main sequence partner but also of material from the outer layers of the underlying white dwarf. This indicates that white dwarf and accreted matter mix prior to the thermonuclear runaway. The processes by which this mixing occurs require further investigation to be understood. In this work, we analyze elemental abundances ejected from hydrodynamic nova models in search of elemental abundance ratios that are useful indicators of the total amount of mixing. We identify the abundance ratios Σ\SigmaCNO/H, Ne/H, Mg/H, Al/H, and Si/H as useful mixing meters in ONe novae. The impact of thermonuclear reaction rate uncertainties on the mixing meters is investigated using Monte Carlo post-processing network calculations with temperature-density evolutions of all mass zones computed by the hydrodynamic models. We find that the current uncertainties in the 30^{30}P(pp,γ\gamma)31^{31}S rate influence the Si/H abundance ratio, but overall the mixing meters found here are robust against nuclear physics uncertainties. A comparison of our results with observations of ONe novae provides strong constraints for classical nova models

    Clinical review: Update of avian influenza A infections in humans

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    Influenza A viruses have a wide host range for infection, from wild waterfowl to poultry to humans. Recently, the cross-species transmission of avian influenza A, particularly subtype H5N1, has highlighted the importance of the non-human subtypes and their incidence in the human population has increased over the past decade. During cross-species transmission, human disease can range from the asymptomatic to mild conjunctivitis to fulminant pneumonia and death. With these cases, however, the risk for genetic change and development of a novel virus increases, heightening the need for public health and hospital measures. This review discusses the epidemiology, host range, human disease, outcome, treatment, and prevention of cross-transmission of avian influenza A into humans

    PERBANDINGAN KATEGORI KEJAHATAN EKONOMI SECARA GLOBAL DAN INDONESIA

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    Penelitian ini bertujuan untuk menganalisis perbedaan kategori fraud yang terjadi secara global dan diakui di Indonesia. Studi ini didasarkan pada data yang dikumpulkan oleh badan-badan atau organisasi pemberantasan fraud, seperti PricewaterhouseCoopers (PwC), Association of Certified Fraud Examiners (ACFE) yang merupakan data hasil survei dari tahun 2016 sampai 2022. Hasil penelitian ini menunjukkan penyalahgunaan aset mendominasi kategori fraud di awal pandemi, namun kemudian menurun setelah pandemi dan digantikan oleh customer fraud dan cybercrime. Begitu juga kasus penipuan di Indonesia, baik sebelum maupun sesudah pandemi, kasus penipuan masih didominasi oleh korupsi

    Referencing Sources of Molecular Spectroscopic Data in the Era of Data Science: Application to the HITRAN and AMBDAS Databases

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    The application described has been designed to create bibliographic entries in large databases with diverse sources automatically, which reduces both the frequency of mistakes and the workload for the administrators. This new system uniquely identifies each reference from its digital object identifier (DOI) and retrieves the corresponding bibliographic information from any of several online services, including the SAO/NASA Astrophysics Data Systems (ADS) and CrossRef APIs. Once parsed into a relational database, the software is able to produce bibliographies in any of several formats, including HTML and BibTeX, for use on websites or printed articles. The application is provided free-of-charge for general use by any scientific database. The power of this application is demonstrated when used to populate reference data for the HITRAN and AMBDAS databases as test cases. HITRAN contains data that is provided by researchers and collaborators throughout the spectroscopic community. These contributors are accredited for their contributions through the bibliography produced alongside the data returned by an online search in HITRAN. Prior to the work presented here, HITRAN and AMBDAS created these bibliographies manually, which is a tedious, time-consuming and error-prone process. The complete code for the new referencing system can be found at \url{https://github.com/hitranonline/refs}.Comment: 11 pages, 5 figures, already published online at https://doi.org/10.3390/atoms802001
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