971 research outputs found

    The Critical Point of Unoriented Random Surfaces with a Non-Even Potential

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    The discrete model of the real symmetric one-matrix ensemble is analyzed with a cubic interaction. The partition function is found to satisfy a recursion relation that solves the model. The double-scaling limit of the recursion relation leads to a Miura transformation relating the contributions to the free energy coming from oriented and unoriented random surfaces. This transformation is the same kind as found with a cuartic interaction.Comment: 20p (Frontpage included

    Critical Lines and Massive Phases in Quantum Spin Ladders with Dimerization

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    We determine the existence of critical lines in dimerized quantum spin ladders in their phase diagram of coupling constants using the finite-size DMRG algorithm. We consider both staggered and columnar dimerization patterns, and antiferromagnetic and ferromagnetic inter-leg couplings. The existence of critical phases depends on the precise combination of these patterns. The nature of the massive phases separating the critical lines are characterized with generalized string order parameters that determine their valence bond solid (VBS) content.Comment: 9 pages 10 figure

    Universality Classes of Diagonal Quantum Spin Ladders

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    We find the classification of diagonal spin ladders depending on a characteristic integer NpN_p in terms of ferrimagnetic, gapped and critical phases. We use the finite algorithm DMRG, non-linear sigma model and bosonization techniques to prove our results. We find stoichiometric contents in cuprate CuO2CuO_2 planes that allow for the existence of weakly interacting diagonal ladders.Comment: REVTEX4 file, 3 color figures, 1 tabl

    Bosonization on a lattice: The emergence of the higher harmonics

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    6 págs.; 2 figs.A general and transparent procedure to bosonize fermions placed on a lattice is presented. Harmonics higher than kF in the one-particle Green function are shown to appear due to the compact character of real electron bands. Quantitative estimations of the role of higher harmonics are made possible by this bosonization technique. © 1995 The American Physical Society.J.F. was supported by DEYCIT Project No. PB93-1248.Peer Reviewe

    New data from Orihuela and Callosa Mountains (Betic Internal Zone, Alicante, SE Spain). Implications for the “Almágride Complex” controversy

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    In this paper, we present the results of the stratigraphic and structural study of the Orihuela and Callosa Mountains (Alicante province, SE Spain), belonging to the Internal Betic Zone. The terrains cropping out in this area had been assigned by previous authors to the Ballabona-Cucharón Complex, lately redefi ned as the Almágride Complex. New data afforded in this work lead us to propose a new stratigraphic succesions, structural division, and geodynamic evolution. We also assign both mountains ranges to the lower Alpujarride Complex, confi rming that the Almágride Complex is not a singular element of the Betic Cordillera.En este trabajo presentamos los resultados del estudio estratigráfi co y estructural de las sierras de Orihuela y Callosa (provincia de Alicante, SE de España), pertenecientes ambas a la Zona Interna Bética. Estas sierras fueron asignadas por autores precedentes al Complejo Ballabona-Cucharón, más tarde redefi nido como Almágride. Los datos presentados en este trabajo nos llevan a proponer una nueva serie estratigráfi ca, división tectónica y evolución geodinámica del sector estudiado. Así mismo, asignamos las unidades reconocidas a la parte inferior del Complejo Alpujárride, confi rmando que el Complejo Almágride no debe ser considerado como elemento singular de la Zona Interna Bética

    Nature s Top 100 Re-Revisited

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    "This is the peer reviewed version of the following article: Martín-Martín, A., Ayllon, J. M., López-Cózar, E. D., & Orduna-Malea, E. (2015). Nature's top 100 Re-revisited. JASIST, 66(12), 2714., which has been published in final form at http://doi.org/10.1002/asi.23570. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."To mark the 50th anniversary of the Science Citation Index, Nature published a list of the 100 most-cited papers of all time. It also included an alternative ranking from data provided by Google Scholar, which, as this letter illustrates, contains certain inconsistencies. This does not, however, diminish the usefulness of Google Scholar, not only in identifying the most-cited articles of all time, but also in reflecting the impact of other document types (especially books), thus redefining the concept of academic impact. Keywords:Martín-Martín, A.; Ayllón, JM.; Delgado López-Cózar, E.; Orduña Malea, E. (2015). Nature s Top 100 Re-Revisited. Journal of the American Society for Information Science and Technology. 66(12):2714-2714. doi:10.1002/asi.23570271427146612Bornmann , L. Nature's top 100 revisited. Journal of the Association for Information Science and Technology http://www.lutz-bornmann.de/icons/top_100.pdfGarfield , E. 2005 The agony and the ecstasy-the history and meaning of the Journal Impact Factor http://www.garfield.library.upenn.edu/papers/jifchicago2005.pdfMartin-Martin , A. Orduna-Malea , E. Ayllon , J.M. Delgado Lopez-Cozar , E. 2014 Does Google Scholar contain all highly cited documents (1950-2013)? http://arxiv.org/abs/1410.8464Van Noorden, R., Maher, B., & Nuzzo, R. (2014). The top 100 papers. Nature, 514(7524), 550-553. doi:10.1038/514550

    The Majorization Arrow in Quantum Algorithm Design

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    We apply majorization theory to study the quantum algorithms known so far and find that there is a majorization principle underlying the way they operate. Grover's algorithm is a neat instance of this principle where majorization works step by step until the optimal target state is found. Extensions of this situation are also found in algorithms based in quantum adiabatic evolution and the family of quantum phase-estimation algorithms, including Shor's algorithm. We state that in quantum algorithms the time arrow is a majorization arrow.Comment: REVTEX4.b4 file, 4 color figures (typos corrected.
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