3,453 research outputs found

    H-Dihyperon in Quark Cluster Model

    Full text link
    The H dihyperon (DH) is studied in the framework of the SU(3) chiral quark model. It is shown that except the σ\sigma chiral field, the overall effect of the other SU(3) chiral fields is destructive in forming a stable DH. The resultant mass of DH in a three coupled channel calculation is ranged from 2225 MeVMeV to 2234 MeVMeV.Comment: 9 pages, emte

    Extended states in 1D lattices: application to quasiperiodic copper-mean chain

    Full text link
    The question of the conditions under which 1D systems support extended electronic eigenstates is addressed in a very general context. Using real space renormalisation group arguments we discuss the precise criteria for determining the entire spertrum of extended eigenstates and the corresponding eigenfunctions in disordered as well as quasiperiodic systems. For purposes of illustration we calculate a few selected eigenvalues and the corresponding extended eigenfunctions for the quasiperiodic copper-mean chain. So far, for the infinite copper-mean chain, only a single energy has been numerically shown to support an extended eigenstate [ You et al. (1991)] : we show analytically that there is in fact an infinite number of extended eigenstates in this lattice which form fragmented minibands.Comment: 10 pages + 2 figures available on request; LaTeX version 2.0

    Phenomenological study of hadron interaction models

    Get PDF
    We present a phenomenological study of three models with different effective degrees of freedom: a Goldstone Boson Exchange (GBE) model which is based on quark-meson couplings, the quark delocalization, color screening model (QDCSM) which is based on quark-gluon couplings with delocalized quark wavefunctions, and the Fujiwara-Nijmegen (FN) mixed model which includes both quark-meson and quark-gluon couplings. We find that for roughly two-thirds of 64 states consisting of pairs of octet and decuplet baryons, the three models predict similar effective baryon-baryon interactions. This suggests that the three very different models, based on different effective degrees of freedom, are nonetheless all compatible with respect to baryon spectra and baryon-baryon interactions. We also discuss the differences between the three models and their separate characteristics.Comment: 30 pages latex, 7 tables, 12 figs; submitted to Phys. Rev.

    Photoresponse of n-ZnO∕p-SiC heterojunction diodes grown by plasma-assisted molecular-beam epitaxy

    Get PDF
    High quality n-ZnOfilms on commercial p-type 6H–SiC substrates have been grown by plasma-assisted molecular-beam epitaxy, and n-ZnO∕p-SiCheterojunction mesa structures have been fabricated. Current-voltage characteristics of the structures had a very good rectifying diode-like behavior with a leakage current less than 2×10−4A/cm2 at −10V, a breakdown voltage greater than 20V, a forward turn on voltage of ∼5V, and a forward current of ∼2A/cm2 at 8V. Photosensitivity of the diodes was studied at room temperature and a photoresponsivity of as high as 0.045A∕W at −7.5V reverse bias was observed for photonenergies higher than 3.0eV

    Statistical correlation for the composite Boson

    Get PDF
    It is well known that the particles in a beam of Boson obeying Bose-Einstein statistics tend to cluster (bunching effect), while the particles in a degenerate beam of Fermion obeying Fermi-Dirac statistics expel each other (anti-bunching effect). Here we investigate, for the first time, the statistical correlation effect for the composite Boson, which is formed from a spin singlet entangled electron pair. By using nonequilibrium Green's function technique, we obtain a positive cross correlation for this kind of the composite Boson when the external voltage is smaller than the gap energy, which demonstrates that a spin singlet entangled electron pair looks like a composite Boson. In the larger voltage limit, the cross correlation becomes negative due to the contribution of the quasiparticles. At large voltages, the oscillation between Fermionic and Bosonic behavior of cross correlation is also observed in the strong coupling regime as one changes the position of the resonant levels. Our result can be easily tested in a three-terminal normal-superconductor-superconductor (N-S-S) hybrid mesoscopic system

    Effect of a tilted magnetic field on the orientation of Wigner crystals

    Full text link
    We study the effect of a tilted magnetic field on the orientation of Wigner crystals by taking account of the width of a quantum well in the zz-direction. It is found that the cohesive energy of the electronic crystal is always lower for the [110][110] direction parallel to the in-plane field. In a realistic sample, a domain structure forms in the electronic solid and each domain orients randomly when the magnetic field is normal to the quantum well. As the field is tilted an angle, the electronic crystal favors to align along a preferred direction which is determined by the in-plane magnetic field. The orientation stabilization is strengthened for wider quantum wells as well as for larger tilted angles. Possible consequence of the tilted field on the transport property in the electronic solid is discussed

    Constraints on the nonuniversal Z^\prime couplings from B\to\pi K, \pi K^{\ast} and \rho K Decays

    Full text link
    Motivated by the large difference between the direct CP asymmetries ACP(Bπ0K)A_{CP}(B^-\to \pi^0 K^-) and ACP(Bˉ0π+K)A_{CP}(\bar{B}^{0}\to \pi^{+} K^{-}), we combine the up-to-date experimental information on BπKB\to\pi K, πK\pi K^{\ast} and ρK\rho K decays to pursue possible solutions with the nonuniversal ZZ^{\prime} model. Detailed analyses of the relative impacts of different types of couplings are presented in four specific cases. Numerically, we find that the new coupling parameters, ξLL\xi^{LL} and ξLR\xi^{LR} with a common nontrivial new weak phase ϕL86\phi_L\sim-86^{\circ}, which are relevant to the ZZ^{\prime} contributions to the electroweak penguin sector C9\triangle C_9 and C7\triangle C_7, are crucial to the observed "πK\pi K puzzle". Furthermore, they are found to be definitely unequal and opposite in sign. We also find that ACP(Bρ0K)A_{CP}(B^-\to \rho^0 K^-) can put a strong constraint on the new ZZ^{\prime} couplings, which implies the ZZ^{\prime} contributions to the coefficient of QCD penguins operator O3O_3 involving the parameter ζLL\zeta^{LL} required.Comment: 27 pages, 6 figures. References and a note adde

    Modification of the Landau-Lifshitz Equation in the Presence of a Spin-Polarized Current in CMR and GMR Materials

    Full text link
    We derive a continuum equation for the magnetization of a conducting ferromagnet in the presence of a spin-polarized current. Current effects enter in the form of a topological term in the Landau-Lifshitz equation . In the stationary situation the problem maps onto the motion of a classical charged particle in the field of a magnetic monopole. The spatial dependence of the magnetization is calculated for a one-dimensional geometry and suggestions for experimental observation are made. We also consider time-dependent solutions and predict a spin-wave instability for large currents.Comment: 4 two-column pages in RevTex, 3 ps-figure

    Large-scale magnetic fields from inflation due to Chern-Simons-like effective interaction

    Full text link
    We discuss the generation of large-scale magnetic fields due to the breaking of the conformal invariance in the electromagnetic field through the CPTCPT-even dimension-six Chern-Simons-like effective interaction with a fermion current in inflationary cosmology. It is shown that the magnetic fields on 1Mpc scale with the field strength of 109\sim 10^{-9}G at the present time can be generated even for the scale of the effective interaction being the Planck scale.Comment: 13 pages, 2 figures, additional explanations include

    p-Adic Mathematical Physics

    Full text link
    A brief review of some selected topics in p-adic mathematical physics is presented.Comment: 36 page
    corecore