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

The origin of the phase separation in partially deuterated κ\kappa-(ET)2_2Cu[N(CN)2_2]Br studied by infrared magneto-optical imaging spectroscopy

The direct observation of the phase separation between the metallic and insulating states of 75 %-deuterated $\kappa$-(ET)$_2$Cu[N(CN)$_2$]Br ($d33$) using infrared magneto-optical imaging spectroscopy is reported, as well as the associated temperature, cooling rate, and magnetic field dependencies of the separation. The distribution of the center of spectral weight ($$) of $d33$ did not change under any of the conditions in which data were taken and was wider than that of the non-deuterated material. This result indicates that the inhomogenity of the sample itself is important as part of the origin of the metal - insulator phase separation.Comment: 4 pages, 3 figures, accepted for publication in Solid State Commu

Generalized Gauge Theories and Weinberg-Salam Model with Dirac-K\"ahler Fermions

We extend previously proposed generalized gauge theory formulation of Chern-Simons type and topological Yang-Mills type actions into Yang-Mills type actions. We formulate gauge fields and Dirac-K\"ahler matter fermions by all degrees of differential forms. The simplest version of the model which includes only zero and one form gauge fields accommodated with the graded Lie algebra of $SU(2|1)$ supergroup leads Weinberg-Salam model. Thus the Weinberg-Salam model formulated by noncommutative geometry is a particular example of the present formulation.Comment: 33 pages, LaTe

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

Incommensurate Mott Insulator in One-Dimensional Electron Systems close to Quarter Filling

A possibility of a metal-insulator transition in molecular conductors has been studied for systems composed of donor molecules and fully ionized anions with an incommensurate ratio close to 2:1 based on a one-dimensional extended Hubbard model, where the donor carriers are slightly deviated from quarter filling and under an incommensurate periodic potential from the anions. By use of the renormalization group method, interplay between commensurability energy on the donor lattice and that from the anion potential has been studied and it has been found that an "incommensurate Mott insulator" can be generated. This theoretical finding will explain the metal-insulator transition observed in (MDT-TS)(AuI$_2$)$_{0.441}$.Comment: 4 pages, 4 figures, submitted to J. Phys. Soc. Jpn. at December 24 200

The quantum space-time of c=-2 gravity

We study the fractal structure of space-time of two-dimensional quantum gravity coupled to c=-2 conformal matter by means of computer simulations. We find that the intrinsic Hausdorff dimension d_H = 3.58 +/- 0.04. This result supports the conjecture d_H = -2 \alpha_1/\alpha_{-1}, where \alpha_n is the gravitational dressing exponent of a spinless primary field of conformal weight (n+1,n+1), and it disfavours the alternative prediction d_H = 2/|\gamma|. On the other hand ~ r^{2n} for n>1 with good accuracy, i.e. the boundary length l has an anomalous dimension relative to the area of the surface.Comment: 46 pages, 16 figures, 32 eps files, using psfig.sty and epsf.st