4,868 research outputs found

    Charge-density waves in one-dimensional Hubbard superlattices

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    We study the formation of charge density waves (CDW's) in one-dimensional Hubbard superlattices, modeled by a repeated pattern of repulsive (U>0) and free (U=0) sites. By means of Lanczos diagonalizations for the ground state, we calculate the charge structure factor. Our results show that while the superlattice structure affects the modulation of the charge density waves, the periodicity can still be predicted through an effective density. We also show that, for a fixed repulsive layer thickness, the periodicity of the CDW is an oscillatory function of the free layer thickness.Comment: 4 pages, 4 figure

    Impurities near an Antiferromagnetic-Singlet Quantum Critical Point

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    Heavy fermion systems, and other strongly correlated electron materials, often exhibit a competition between antiferromagnetic (AF) and singlet ground states. Using exact Quantum Monte Carlo (QMC) simulations, we examine the effect of impurities in the vicinity of such AF- singlet quantum critical points, through an appropriately defined impurity susceptibility, χimp\chi_{imp}. Our key finding is a connection, within a single calculational framework, between AF domains induced on the singlet side of the transition, and the behavior of the nuclear magnetic resonance (NMR) relaxation rate 1/T11/T_1. We show that local NMR measurements provide a diagnostic for the location of the QCP which agrees remarkably well with the vanishing of the AF order parameter and large values of χimp\chi_{imp}. We connect our results with experiments on Cd-doped CeCoIn5_5

    Genome-wide transcriptomics analysis identifies sox7 and sox18 as specifically regulated by gata4 in cardiomyogenesis

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    This work was supported by British Heart Foundation (BHF Project Grant no PG/13/23/30080 to B.A.A and S.H.), Biotechnology and Biological Sciences Research Council (BB/M001695/1 to S.H.) and the University of Aberdeen (for A.T.L). Acknowledgements We’re grateful to Ms Yvonne Turnbull and Ms Kate Watt for technical assistance and lab management. We would like to thank Professor Cedric Blanpain and Dr Xionghui Li from Université Libre de Bruxelles for providing training of ES cell manipulation and Mesp1/Gata4 cell lines. We are grateful to Professor Todd Evans from Weill Cornell Medical College for generously providing iGata ES cell lines. We also would like to thank Professor Aaron Zorn and Scott Rankin for providing Xsox18 plasmid.Peer reviewedPublisher PD
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