43,901 research outputs found

    Gluon Propagators and Confinement

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    We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at beta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16 (deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to avoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon propagators show quite different behavior from those of massless gauge fields: (1) In the confinement phase, G(t) shows massless behavior at small and large t, while around 5<t<15 it behaves as massive particle, and (2) effective mass observed in G(z) becomes larger as z increases. (3) In the deconfinement phase, G(z) shows also massive behavior but effective mass is less than in the confinement case. In all cases, slope masses are increasing functions of t or z, which can not be understood as addtional physical poles.Comment: 6 pages in Postscrip

    A Case Report of Folie\u27a Deux: Husband-and-Wife

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    Shared paranoid disorder is a relatively rare psychiatric disorder in which paranoid delusions are transferred from one individual to one or more other susceptible person(s) in close association. Folie a deux describes a shared paranoid disorder involving two people and is characterized by a complex dependant relationship between the involved individuals. Provided there is no additional underlying psychopathology, there is a good prognosis for the submissive partner. Here we present a case report and discussion off folie a deux involving a husband and wife. Although folie a deux is a relatively uncommon disorder, it is important to recognize such cases due to the potential for recovery in the submissive partner

    Localization length of a soliton from a non-magnetic impurity in a general double-spin-chain model

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    A localization length of a free-spin soliton from a non-magnetic impurity is deduced in a general double-spin-chain model (J0−J1−J2−J3J_0-J_1-J_2-J_3 model). We have solved a variational problem which employs the nearest-neighbor singlet-dimer basis. The wave function of a soliton is expressed by the Airy function, and the localization length (Ο)(\xi) is found to obey a power law of the dimerization (J2−J3)(J_2-J_3) with an exponent -1/3; Ο∌(J2−J3)−1/3\xi\sim (J_2-J_3)^{-1/3}. This explains why NaV_2O_5 does not show the antiferromagnetic order, while CuGeO_3 does by impurity doping. When the gap exists by the bond-dimerization, a soliton is localized and no order is expected. Contrary, there is a possibility of the order when the gap is mainly due to frustration.Comment: 4 pages, REVTeX, Figures are in eps-file

    Universal low-temperature properties of quantum and classical ferromagnetic chains

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    We identify the critical theory controlling the universal, low temperature, macroscopic properties of both quantum and classical ferromagnetic chains. The theory is the quantum mechanics of a single rotor. The mapping leads to an efficient method for computing scaling functions to high accuracy.Comment: 4 pages, 2 tables and 3 Postscript figure

    Exotic Properties of Light Nuclei and their Neutron Capture Cross Sections

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    We have investigated the implications of the neutron halo configuration, observed in the ground-state of some neutron-rich light nuclei, on neutron radiative transition processes. In particular, we have studied the influence of the neutron halo on the direct radiative capture (DRC) process. The energy dependence as well as the strength of E1 emission due to incident p-wave neutrons is strongly influenced by the halo configuration of the residual nucleus capturing state. We have compared the calculated 10Be(n,gamma)11Be DRC cross section with that derived from the experiment in the inverse kinematics (Coulomb dissociation of 11Be). We show from the comparison that some important information on the structure of the halo nucleus 11Be can be derived.Comment: Contribution to the 4th International Seminar on Interaction of Neutrons with Nuclei, Dubna (Russia), April 199

    Theoretical analysis of the experiments on the double-spin-chain compound -- KCuCl3_3

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    We have analyzed the experimental susceptibility data of KCuCl3_3 and found that the data are well-explained by the double-spin-chain models with strong antiferromagnetic dimerization. Large quantum Monte Carlo calculations were performed for the first time in the spin systems with frustration. This was made possible by removing the negative-sign problem with the use of the dimer basis that has the spin-reversal symmetry. The numerical data agree with the experimental data within 1% relative errors in the whole temperature region. We also present a theoretical estimate for the dispersion relation and compare it with the recent neutron-scattering experiment. Finally, the magnitude of each interaction bond is predicted.Comment: 4 pages, REVTeX, 5 figures in eps-file

    Quantum Phase Transitions and the Hidden Order in a Two-Chain Extended Boson Hubbard Model at Half-Odd-Integer Fillings

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    We study the phase diagram of two weakly coupled one-dimensional dipolar boson chains at half-odd-integer fillings. We find that the system contains a rich phase diagram. Four different phases are found. They are the Mott insulators, the single-particle resonant superfluid, the paired superfluid, and the bond- or inter-chain density waves. Moreover, the Mott insulating phase can be further classified according to a hidden string order parameter, which is analogous to the one investigated recently in the one-dimensional boson Mott insulator at integer fillings.Comment: 7 pages, 2 figure

    Effects of Chemical Potential on Hadron Masses at Finite Temperature

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    We study the effects of the chemical potential on the ρ\rho meson mass at finite temperature. Our preliminary results show that some effects are seen in the vicinity of the phase transition point. Although the signal is still too noisy to obtain conclusive physical results within limited statistics, the mass susceptibility is consistent with zero.Comment: LATTICE98(hightemp), 3 page
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