1,172 research outputs found

    Comparing Fifty Natural Languages and Twelve Genetic Languages Using Word Embedding Language Divergence (WELD) as a Quantitative Measure of Language Distance

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    We introduce a new measure of distance between languages based on word embedding, called word embedding language divergence (WELD). WELD is defined as divergence between unified similarity distribution of words between languages. Using such a measure, we perform language comparison for fifty natural languages and twelve genetic languages. Our natural language dataset is a collection of sentence-aligned parallel corpora from bible translations for fifty languages spanning a variety of language families. Although we use parallel corpora, which guarantees having the same content in all languages, interestingly in many cases languages within the same family cluster together. In addition to natural languages, we perform language comparison for the coding regions in the genomes of 12 different organisms (4 plants, 6 animals, and two human subjects). Our result confirms a significant high-level difference in the genetic language model of humans/animals versus plants. The proposed method is a step toward defining a quantitative measure of similarity between languages, with applications in languages classification, genre identification, dialect identification, and evaluation of translations

    The effect of sublattice symmetry breaking on the electronic properties of a doped graphene

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    Motivated by a number of recent experimental studies, we have carried out the microscopic calculation of the quasiparticle self-energy and spectral function in a doped graphene when a symmetry breaking of the sublattices is occurred. Our systematic study is based on the many-body G0_0W approach that is established on the random phase approximation and on graphene's massive Dirac equation continuum model. We report extensive calculations of both the real and imaginary parts of the quasiparticle self-energy in the presence of a gap opening. We also present results for spectral function, renormalized Fermi velocity and band gap renormalization of massive Dirac Fermions over a broad range of electron densities. We further show that the mass generating in graphene washes out the plasmaron peak in spectral weight.Comment: 22 Pages, 10 Figure

    Comparative study of screened inter-layer interactions in the Coulomb drag effect in bilayer electron systems

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    Coulomb drag experiments in which the inter-layer resistivity is measured are important as they provide information on the Coulomb interactions in bilayer systems. When the layer densities are low correlation effects become significant to account for the quantitative description of experimental results. We investigate systematically various models of effective inter-layer interactions in a bilayer system and compare our results with recent experiments. In the low density regime, the correlation effects are included via the intra- and inter-layer local-field corrections. We employ several theoretical approaches to construct static local-field corrections. Our comparative study demonstrates the importance of including the correlation effects accurately in the calculation of drag resistivity. Recent experiments performed at low layer densities are adequately described by effective inter-layer interactions incorporating static correlations.Comment: Final Version. To appear in Phys. Rev.

    Theory of correlations in strongly interacting fluids of two-dimensional dipolar bosons

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    Ground-state properties of a two-dimensional fluid of bosons with repulsive dipole-dipole interactions are studied by means of the Euler-Lagrange hypernetted-chain approximation. We present a self-consistent semi-analytical theory of the pair distribution function g(r)g(r) and ground-state energy of this system. Our approach is based on the solution of a zero-energy scattering Schr\"{o}dinger equation for the "pair amplitude" g(r)\sqrt{g(r)} with an effective potential from Jastrow-Feenberg correlations. We find excellent agreement with quantum Monte Carlo results over a wide range of coupling strength, nearly up to the critical coupling for the liquid-to-crystal quantum phase transition. We also calculate the one-body density matrix and related quantities, such as the momentum distribution function and the condensate fraction.Comment: 8 pages, 8 figures, submitte

    Effective electron-electron interactions and magnetic phase transition in a two-dimensional electron liquid

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    Cataloged from PDF version of article.We investigate the spin-dependent effective electron-electron interactions in a uniform system of two-dimensional electrons to understand the spontaneous magnetization expected to occur at very low density. For this purpose, we adopt the Kukkonen-Overhauser form for the effective interactions which are built by accurately determined local-field factors describing the charge and spin fluctuations. The critical behavior of the effective interaction for parallel spin electrons allows us to quantitatively locate the transition to the ferromagnetic state at r(s) approximate to 27. When the finite width effects are approximately taken into account the transition occurs at r(s) approximate to 30 in agreement with recent quantum Monte Carlo calculations. (C) 2007 Elsevier Ltd. All rights reserved
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