1,849 research outputs found

    Highest weight Macdonald and Jack Polynomials

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    Fractional quantum Hall states of particles in the lowest Landau levels are described by multivariate polynomials. The incompressible liquid states when described on a sphere are fully invariant under the rotation group. Excited quasiparticle/quasihole states are member of multiplets under the rotation group and generically there is a nontrivial highest weight member of the multiplet from which all states can be constructed. Some of the trial states proposed in the literature belong to classical families of symmetric polynomials. In this paper we study Macdonald and Jack polynomials that are highest weight states. For Macdonald polynomials it is a (q,t)-deformation of the raising angular momentum operator that defines the highest weight condition. By specialization of the parameters we obtain a classification of the highest weight Jack polynomials. Our results are valid in the case of staircase and rectangular partition indexing the polynomials.Comment: 17 pages, published versio

    The Partition Function of Multicomponent Log-Gases

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    We give an expression for the partition function of a one-dimensional log-gas comprised of particles of (possibly) different integer charge at inverse temperature {\beta} = 1 (restricted to the line in the presence of a neutralizing field) in terms of the Berezin integral of an associated non- homogeneous alternating tensor. This is the analog of the de Bruijn integral identities [3] (for {\beta} = 1 and {\beta} = 4) ensembles extended to multicomponent ensembles.Comment: 14 page

    Why is gold such a good catalyst for oxygen reduction in alkaline media?

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    The two faces of gold: The reduction of oxygen on gold electrodes in alkaline solutions has been investigated theoretically. The most favorable reaction leads directly to adsorbed O2- , but the activation energy for a two-step pathway, in which the first step is an outersphere electron transfer to give solvated O2-, is only slightly higher. d-band catalysis, which dominates oxygen reduction in acid media, plays no role. The reason why the reaction is slow in acid media is also explained.Fil: Quaino, Paola Monica. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Electroquímica Aplicada e Ingeniería Electroquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Luque, N. B.. Institute of Theoretical Chemistry; AlemaniaFil: Nazmutdinov, Renat. Kazan National Research Technological University; RusiaFil: Santos, Elisabeth. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Schmickler, Wolfgang. Institute of Theoretical Chemistry; Alemani

    Critical Networks Exhibit Maximal Information Diversity in Structure-Dynamics Relationships

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    Network structure strongly constrains the range of dynamic behaviors available to a complex system. These system dynamics can be classified based on their response to perturbations over time into two distinct regimes, ordered or chaotic, separated by a critical phase transition. Numerous studies have shown that the most complex dynamics arise near the critical regime. Here we use an information theoretic approach to study structure-dynamics relationships within a unified framework and how that these relationships are most diverse in the critical regime

    Asymptotics of Selberg-like integrals: The unitary case and Newton's interpolation formula

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    We investigate the asymptotic behavior of the Selberg-like integral 1N![0,1]Nx1pi<j(xixj)2ixia1(1xi)b1dxi \frac1{N!}\int_{[0,1]^N}x_1^p\prod_{i<j}(x_i-x_j)^2\prod_ix_i^{a-1}(1-x_i)^{b-1}dx_i, as NN\to\infty for different scalings of the parameters aa and bb with NN. Integrals of this type arise in the random matrix theory of electronic scattering in chaotic cavities supporting NN channels in the two attached leads. Making use of Newton's interpolation formula, we show that an asymptotic limit exists and we compute it explicitly

    Probing photo-ionization: simulations of positive streamers in varying N2:O2 mixtures

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    Photo-ionization is the accepted mechanism for the propagation of positive streamers in air though the parameters are not very well known; the efficiency of this mechanism largely depends on the presence of both nitrogen and oxygen. But experiments show that streamer propagation is amazingly robust against changes of the gas composition; even for pure nitrogen with impurity levels below 1 ppm streamers propagate essentially with the same velocity as in air, but their minimal diameter is smaller, and they branch more frequently. Additionally, they move more in a zigzag fashion and sometimes exhibit a feathery structure. In our simulations, we test the relative importance of photo-ionization and of the background ionization from pulsed repetitive discharges, in air as well as in nitrogen with 1 ppm O2 . We also test reasonable parameter changes of the photo-ionization model. We find that photo- ionization dominates streamer propagation in air for repetition frequencies of at least 1 kHz, while in nitrogen with 1 ppm O2 the effect of the repetition frequency has to be included above 1 Hz. Finally, we explain the feather-like structures around streamer channels that are observed in experiments in nitrogen with high purity, but not in air.Comment: 12 figure

    Development and RF-Performance of AlGaN/GaN and InAlN/GaN HEMTs on Large-Diameter High-Resistivity Silicon Substrates

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    A CMOS-compatible industrial processing and RF analysis of 150 mm GaN-on-HR-Si substrates with AlGaN and InAlN barrier is presented. Process development along with transfer to large-wafer scale is shown and some HEMT calibration devices produced on AlGaN/GaN following the aforementioned procedure are characterized in terms of RF-performance by using a set of measured multi-bias S-parameters. An automatic small-signal equivalent circuit extraction strategy for these AlGaN/GaN DUTs is validated and some de-embedded figures of merit are drawn out in order to initially evaluate this promising technology.This work is supported by the I Plan Propio de la Univ. de Málaga (PhD Grant-401), and the European Microwave Association™ by the EuMA Internship Award 2021 edition. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Can an Amino Acid Mixture Alleviate Gastrointestinal Symptoms in Neuroendocrine Tumor Patients?

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    Background: Neuroendocrine tumors, although relatively rare in incidence, are now the second most prevalent gastrointestinal neoplasm owing to indolent disease biology. A small but significant sub-group of neuroendocrine tumor patients suffer from diarrhea. This is usually secondary to carcinoid syndrome but can also be a result of short gut syndrome, bile acid excess or iatrogenic etiologies. Recently, an amino acid based oral rehydration solution (enterade® Advanced Oncology Formula) was found to have anti-diarrheal properties in preclinical models. Methods: A retrospective chart review of all NET patients treated with enterade® AO was performed after IRB approval. Results: Ninety-eight NET patients who had received enterade® AO at our clinic from May 2017 through June 2019 were included. Patients (N = 49 of 98) with follow up data on bowel movements (BMs) were included for final analysis. Eighty-four percent of patients (41/49) had fewer BMs after taking enterade® AO and 66% (27/41) reported more than 50% reduction in BM frequency. The mean number of daily BMs was 6.6 (range, 3–20) at baseline before initiation of therapy, while the mean number of BMs at 1 week time point post enterade® AO was 2.9 (range, 0–11). Conclusions: Our retrospective observations are encouraging and support prospective validation with appropriate controls in NET patients. This is first published report of the potential anti-diarrheal activity of enterade® AO in NET patients
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