22,626 research outputs found

    Speculations on Isolated Lepton Events at HERA

    Full text link
    Speculations on mechanisms which might be responsible for events with an isolated high p_T lepton, a hadron jet and missing energy, as observed in the H1 experiment at HERA, are discussed.Comment: LaTeX, 6 pages, 2 figures, presented at the XXXI Conference of Theoretical Physics "Matter to the Deepest", Ustron, Poland, September 5-11, 200

    Inflation with blowing-up solution of cosmological constant problem

    Get PDF
    The cosmological constant problem is how one chooses, without fine-tuning, one singular point Λeff=0\Lambda_{eff}=0 for the 4D cosmological constant. We argue that some recently discovered {\it weak self-tuning} solutions can be viewed as blowing-up this one point into a band of some parameter. These weak self-tuning solutions may have a virtue that only de Sitter space solutions are allowed outside this band, allowing an inflationary period. We adopt the hybrid inflation at the brane to exit from this inflationary phase and to enter into the standard Big Bang cosmology.Comment: LaTeX file of 20 pages including 2 eps figure

    Magnetic Excitations and Continuum of a Field-Induced Quantum Spin Liquid in α\alpha-RuCl3_3

    Full text link
    We report on terahertz spectroscopy of quantum spin dynamics in α\alpha-RuCl3_3, a system proximate to the Kitaev honeycomb model, as a function of temperature and magnetic field. An extended magnetic continuum develops below the structural phase transition at Ts2=62T_{s2}=62K. With the onset of a long-range magnetic order at TN=6.5T_N=6.5K, spectral weight is transferred to a well-defined magnetic excitation at ℏω1=2.48\hbar \omega_1 = 2.48meV, which is accompanied by a higher-energy band at ℏω2=6.48\hbar \omega_2 = 6.48meV. Both excitations soften in magnetic field, signaling a quantum phase transition at Bc=7B_c=7T where we find a broad continuum dominating the dynamical response. Above BcB_c, the long-range order is suppressed, and on top of the continuum, various emergent magnetic excitations evolve. These excitations follow clear selection rules and exhibit distinct field dependencies, characterizing the dynamical properties of the field-induced quantum spin liquid

    A Characterization of Visibility Graphs for Pseudo-Polygons

    Full text link
    In this paper, we give a characterization of the visibility graphs of pseudo-polygons. We first identify some key combinatorial properties of pseudo-polygons, and we then give a set of five necessary conditions based off our identified properties. We then prove that these necessary conditions are also sufficient via a reduction to a characterization of vertex-edge visibility graphs given by O'Rourke and Streinu

    Reconstruction of Fundamental SUSY Parameters

    Get PDF
    We summarize methods and expected accuracies in determining the basic low-energy SUSY parameters from experiments at future e+^+e−^- linear colliders in the TeV energy range, combined with results from LHC. In a second step we demonstrate how, based on this set of parameters, the fundamental supersymmetric theory can be reconstructed at high scales near the grand unification or Planck scale. These analyses have been carried out for minimal supergravity [confronted with GMSB for comparison], and for a string effective theory.Comment: 8 pages, latex, 7 figures, expanded version of contributions to the proceedings of ICHEP.2002 (Amstersdam) and LCWS.2002 (Jeju Island

    Charge and current fluctuations in a superconducting single electron transistor near a Cooper pair resonance

    Full text link
    We analyze charge tunneling statistics and current noise in a superconducting single-electron transistor in a regime where the Josephson-quasiparticle cycle is the dominant mechanism of transport. Due to the interplay between Coulomb blockade and Josephson coherence, the probability distribution for tunneling events strongly deviates from a Poissonian and displays a pronounced even--odd asymmetry in the number of transmitted charges. The interplay between charging and coherence is reflected also in the zero-frequency current noise which is significantly quenched when the quasi-particle tunneling rates are comparable to the coherent Cooper-pair oscillation frequency. Furthermore the finite frequency spectrum shows a strong enhancement near the resonant transition frequency for Josephson tunneling.Comment: 10 pages, 11 figure

    Shot Noise and Full Counting Statistics from Non-equilibrium Plasmons in Luttinger-Liquid Junctions

    Full text link
    We consider a quantum wire double junction system with each wire segment described by a spinless Luttinger model, and study theoretically shot noise in this system in the sequential tunneling regime. We find that the non-equilibrium plasmonic excitations in the central wire segment give rise to qualitatively different behavior compared to the case with equilibrium plasmons. In particular, shot noise is greatly enhanced by them, and exceeds the Poisson limit. We show that the enhancement can be explained by the emergence of several current-carrying processes, and that the effect disappears if the channels effectively collapse to one due to, {\em e.g.}, fast plasmon relaxation processes.Comment: 9 pages; IOP Journal style; several changes in the tex

    Valuable rubidium extraction from potassium reduced seawater brine

    Full text link
    © 2017 Elsevier Ltd Extraction of rubidium (Rb) which is an economically valuable metal from seawater reverse osmosis (SWRO) brine is beneficial. However, potassium (K) in SWRO brine hinders Rb extraction. Natural clinoptilolite zeolite in powder form was able to selectively remove K from SWRO brine (Langmuir maximum sorption, Qmax (cal.) = 57.47 ± 0.09 mg/g). An integrated submerged membrane sorption reactor (SMSR) containing zeolite powder achieved 65% K removal from SWRO brine. Periodic replacement of zeolite in SMSR, coupled with membrane backwashing was effective in maintaining a high K removal efficiency and a stable transmembrane pressure. Less than 5% Rb losses occurred along with K sorption, establishing the high K selectivity by zeolite in SWRO brine. Utilization of K loaded zeolite as a slow release fertilizer would be beneficial for agriculture. In SWRO brine with reduced K contents, the Rb sorption efficiency of polymer encapsulated potassium copper hexacyanoferrate (KCuFC(PAN)) sorbent, increased significantly from 18% to 83%
    • 

    corecore