23,804 research outputs found

    Evaluation of specific heat for superfluid helium between 0 - 2.1 K based on nonlinear theory

    Get PDF
    The specific heat of liquid helium was calculated theoretically in the Landau theory. The results deviate from experimental data in the temperature region of 1.3 - 2.1 K. Many theorists subsequently improved the results of the Landau theory by applying temperature dependence of the elementary excitation energy. As well known, many-body system has a total energy of Galilean covariant form. Therefore, the total energy of liquid helium has a nonlinear form for the number distribution function. The function form can be determined using the excitation energy at zero temperature and the latent heat per helium atom at zero temperature. The nonlinear form produces new temperature dependence for the excitation energy from Bose condensate. We evaluate the specific heat using iteration method. The calculation results of the second iteration show good agreement with the experimental data in the temperature region of 0 - 2.1 K, where we have only used the elementary excitation energy at 1.1 K.Comment: 6 pages, 3 figures, submitted to Journal of Physics: Conference Serie

    Excited nucleon spectrum from lattice QCD with maximum entropy method

    Full text link
    We study excited states of the nucleon in quenched lattice QCD with the spectral analysis using the maximum entropy method. Our simulations are performed on three lattice sizes 163×3216^3\times 32, 243×3224^3\times 32 and 323×3232^3\times 32, at β=6.0\beta=6.0 to address the finite volume issue. We find a significant finite volume effect on the mass of the Roper resonance for light quark masses. After removing this systematic error, its mass becomes considerably reduced toward the direction to solve the level order puzzle between the Roper resonance N′(1440)N'(1440) and the negative-parity nucleon N∗(1535)N^*(1535).Comment: Lattice2003(spectrum), 3 pages, 4 figure

    Bayesian approach to the first excited nucleon state in lattice QCD

    Get PDF
    We present preliminary results from the first attempt to reconstruct the spectral function in the nucleon and Δ\Delta channels from lattice QCD data using the maximum entropy method (MEM). An advantage of the MEM analysis is to enable us to access information of the excited state spectrum. Performing simulations on two lattice volumes, we confirm the large finite size effect on the first excited nucleon state in the lighter quark mass region.Comment: Lattice2002(spectrum), Latex with espcrc2.sty, 3 pages, 3 figure

    Realization of a collective decoding of codeword states

    Full text link
    This was also extended from the previous article quant-ph/9705043, especially in a realization of the decoding process.Comment: 6 pages, RevTeX, 4 figures(EPS

    The alphaalphas2alpha alpha_s^2 corrections to the first moment of the polarized virtual photon structure function g1gamma(x,Q2,P2)g_1^gamma(x,Q^2,P^2)

    Full text link
    We present the next-to-next-to-leading order (alphaalphas2alpha alpha_s^2) corrections to the first moment of the polarized virtual photon structure function g1gamma(x,Q2,P2)g_1^gamma(x,Q^2,P^2) in the kinematical region Lambda2llP2llQ2Lambda^2 ll P^2 ll Q^2, where −Q2(−P2)-Q^2(-P^2) is the mass squared of the probe (target) photon and LambdaLambda is the QCD scale parameter. In order to evaluate the three-loop-level photon matrix element of the flavor singlet axial current, we resort to the Adler-Bardeen theorem for the axial anomaly and we calculate in effect the two-loop diagrams for the photon matrix element of the gluon operator. The alphaalphas2alpha alpha_s^2 corrections are found to be about 3% of the sum of the leading order (alphaalpha) andthe next-to-leading order (alphaalphasalpha alpha_s) contributions, when Q2=30sim100rmGeV2Q^2=30 sim 100 {rm GeV}^2and P2=3rmGeV2P^2=3{rm GeV}^2, and the number of active quark flavors nfn_f is three to five.Comment: 21 page

    Self-force Regularization in the Schwarzschild Spacetime

    Full text link
    We discuss the gravitational self-force on a particle in a black hole space-time. For a point particle, the full (bare) self-force diverges. The metric perturbation induced by a particle can be divided into two parts, the direct part (or the S part) and the tail part (or the R part), in the harmonic gauge, and the regularized self-force is derived from the R part which is regular and satisfies the source-free perturbed Einstein equations. But this formulation is abstract, so when we apply to black hole-particle systems, there are many problems to be overcome in order to derive a concrete self-force. These problems are roughly divided into two parts. They are the problem of regularizing the divergent self-force, i.e., ``subtraction problem'' and the problem of the singularity in gauge transformation, i.e., ``gauge problem''. In this paper, we discuss these problems in the Schwarzschild background and report some recent progress.Comment: 34 pages, 2 figures, submitted to CQG, special volume for Radiation Reaction (CAPRA7

    J/ψJ/\psi and ηc\eta_c in the Deconfined Plasma from Lattice QCD

    Full text link
    Analyzing correlation functions of charmonia at finite temperature (TT) on 323×(32−96)32^3\times(32-96) anisotropic lattices by the maximum entropy method (MEM), we find that J/ψJ/\psi and ηc\eta_c survive as distinct resonances in the plasma even up to T≃1.6TcT \simeq 1.6 T_c and that they eventually dissociate between 1.6Tc1.6 T_c and 1.9Tc1.9 T_c (TcT_c is the critical temperature of deconfinement). This suggests that the deconfined plasma is non-perturbative enough to hold heavy-quark bound states. The importance of having sufficient number of temporal data points in MEM analyses is also emphasized.Comment: 4 pages, 4 figures, REVTEX, version to appear in Physical Review Letter

    Diffeomorphism on Horizon as an Asymptotic Isometry of Schwarzschild Black Hole

    Full text link
    It is argued that the diffeomorphism on the horizontal sphere can be regarded as a nontrivial asymptotic isometry of the Schwarzschild black hole. We propose a new boundary condition of asymptotic metrics near the horizon and show that the condition admits the local time-shift and diffeomorphism on the horizon as the asymptotic symmetry.Comment: 18 pages, no figures, corrected some typo
    • …
    corecore