Brown-Rho Scaling in the Strong Coupling Lattice QCD

We examine the Brown-Rho scaling for meson masses in the strong coupling limit of lattice QCD with one species of staggered fermion. Analytical expression of meson masses is derived at finite temperature and chemical potential. We find that meson masses are approximately proportional to the equilibrium value of the chiral condensate, which evolves as a function of temperature and chemical potential.Comment: Prepared for Chiral Symmetry in Hadron and Nuclear Physics (Chiral07), Nov. 13-16, 2007, Osaka, Japa

Phase diagram at finite temperature and quark density in the strong coupling region of lattice QCD for color SU(3)

We study the phase diagram of quark matter at finite temperature (T) and chemical potential (mu) in the strong coupling region of lattice QCD for color SU(3). Baryon has effects to extend the hadron phase to a larger mu direction relative to Tc at low temperatures in the strong coupling limit. With the 1/g^2 corrections, Tc is found to decrease rapidly as g decreases, and the shape of the phase diagram becomes closer to that expected in the real world.Comment: 4 pages, 4 figures. To appear in the proceedings of the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, Shanghai, China, Nov. 14-20, 2006 (Quark Matter 2006

Optimal design of efficient IPM motor using finite element method

Techniques for the optimal design of permanent magnet motors considering rotation are investigated. The nonconforming mesh technique is used to take into account the rotation of the rotor. It is shown that the technique is especially useful for the optimal design using the finite element method, because no modification of mesh is necessary during the rotation. The mesh at each angle of rotation can be obtained by only combining meshes of a rotor and a stator. By using the combined optimization technique of the experimental design method and Rosenbrock's method, the number of FEM calculations can be reduced. By applying the optimal design method, about 40% of volume of permanent magnet of IPM motor and about 15% of the torque ripple can be reduced</p

Inertial manifolds for Burgers' original model system of turbulence

AbstractThe existence of inertial manifolds for Burgers' original mathematical model system of turbulence is investigated. The system consists of two equations and enjoys the characteristic quantity: the Reynolds number. Our object in this article is to express the existence in terms of this Reynolds number. The difficulty of first order derivatives is circumvented by the method originally due to M. Kwak

SuprimeCam Observation of Sporadic Meteors during Perseids 2004

We report the serendipitous findings of 13 faint meteors and 44 artificial space objects by Subaru SuprimeCam imaging observations during 11-16 August 2004. The meteors, at about 100km altitude, and artificial satellites/debris in orbit, at 500km altitude or higher, were clearly discriminated by their apparent defocused image sizes. CCD photometry of the 13 meteors, including 1 Perseid, 1 Aquarid, and 11 sporadic meteors, was performed. We defined a peak video-rate magnitude by comparing the integrated photon counts from the brightest portion of the track traversed within 33ms to those from a 0-mag star during the same time duration. This definition gives magnitudes in the range 4.0< V_{vr} <6.4 and 4.1< I_{vr}<5.9 for these 13 meteors. The corresponding magnitude for virtual naked-eye observers could be somewhat fainter especially for the V-band observation, in which the [OI] 5577 line lasting about 1 sec as an afterglow could contribute to the integrated flux of the present 5-10 min CCD exposures. Although the spatial resolution is insufficient to resolve the source size of anything smaller than about 1 m, we developed a new estimate of the collisionally excited column diameter of these meteors. A diameter as small as a few mm was derived from their collisionally excited photon rates, meteor speed, and the volume density of the oxygen atoms at the 100km altitude. The actual column diameter of the radiating zone, however, could be as large as few 100m because the excited atoms travel that distance before they emit forbidden lines in 0.7 sec of its average lifetime. Among the 44 artificial space objects, we confirmed that 17 were cataloged satellites/space debris.Comment: 14 pages, 13 figures, 5 tables, submitted to PAS

Tables of Hyperonic Matter Equation of State for Core-Collapse Supernovae

We present sets of equation of state (EOS) of nuclear matter including hyperons using an SU_f(3) extended relativistic mean field (RMF) model with a wide coverage of density, temperature, and charge fraction for numerical simulations of core collapse supernovae. Coupling constants of Sigma and Xi hyperons with the sigma meson are determined to fit the hyperon potential depths in nuclear matter, U_Sigma(rho_0) ~ +30 MeV and U_Xi(rho_0) ~ -15 MeV, which are suggested from recent analyses of hyperon production reactions. At low densities, the EOS of uniform matter is connected with the EOS by Shen et al., in which formation of finite nuclei is included in the Thomas-Fermi approximation. In the present EOS, the maximum mass of neutron stars decreases from 2.17 M_sun (Ne mu) to 1.63 M_sun (NYe mu) when hyperons are included. In a spherical, adiabatic collapse of a 15$M_\odot$ star by the hydrodynamics without neutrino transfer, hyperon effects are found to be small, since the temperature and density do not reach the region of hyperon mixture, where the hyperon fraction is above 1 % (T > 40 MeV or rho_B > 0.4 fm^{-3}).Comment: 23 pages, 6 figures (Fig.3 and related comments on pion potential are corrected in v3.