A tensor-network variational formalism of thermofield dynamics is introduced. The formalism relates the original Hilbert space with its tilde space by a product of two copies of a tensor network. Then, their interface becomes an event horizon, and the logarithm of the tensor rank corresponds to the black hole entropy. Eventually, a multiscale entanglement renormalization ansatz reproduces an anti-de Sitter black hole at finite temperature. Our finding shows rich functionalities of multiscale entanglement renormalization ansatz as efficient graphical representation of AdS/CFT correspondence.

Yang-Mills theory with flavor quarks in the dS 4 is studied through the dual supergravity in the AdS 5 × S 5 background with non-trivial dilaton and axion. The flavor quarks are introduced by embedding a probe D7 brane. We find that the dynamical properties of YM theory in the dS 4 are similar to the case of the finite temperature theory given by the 5d AdS-Schwarzschild background. In the case of dS 4 , however, contrary to the finite temperature case, the gauge field condensate plays an important role on the dynamical properties of quarks. We also give the quark-antiquark potential and meson spectra to find possible quarkbound states. And we arrive at the conclusion that, while the quarks are not confined in the dS 4 , we could find stable meson states at very small cosmological constant as expected in the present universe. But there would be no hadrons at early universe as in the inflation era. † gouroku@dontaku.fit.ac.jp

We study baryons in SU(N) gauge theories, according to the gauge/string correspondence based on IIB string theory. The D5 brane, in which N fundamental strings are dissolved as a color singlet, is introduced as the baryon vertex, and its configurations are studied. We find point-and split-type of vertex. In the latter case, two cusps appears and they are connected by a flux composed of dissolved fundamental strings with a definite tension. In both cases, N fundamental quarks are attached on the cusp(s) of the vertex to cancel the surface term. In the confining phase, we find that the quarks in the baryon feel the potential increasing linearly with the distance from the vertex. At finite temperature and in the deconfining phase, we find stable k-quarks "baryons", which are constructed of arbitrary number of k(< N) quarks.

The liver contrast effects of Sonazoid in two ultrasonographic imaging modes, gray-scale conventional and harmonic, were examined as a time-related study in normal rabbits, and evaluated quantitatively and visually with tumor-model rabbits to estimate the diagnostic potential. Peak enhancement of vessels and parenchyma was observed 1 min after injection in both modes, although signal enhancement in the parenchyma lasted for 120 min compared with rapid decay (5-10 min) in vessels. When Sonazoid was intravenously injected into metastatic carcinoma-model (VX-2) rabbits, all hepatic tumors showed ring enhancement in the early phase followed by clear contrast defects in the delayed phase, because signal enhancement remained only in normal parenchyma. Visual analysis scores for the diagnosis of tumors were improved by Sonazoid injection, and the videodensitometric differences between tumor and normal tissues were significantly greater after injection. Although the harmonic mode tended to show better contrast effects, the conventional mode provided significant contrast enhancement in this hepatic tumor-model. Sonazoid might be useful for the detection of undifferentiated tumors in the liver by making it possible to visualize neovascularity in the early phase and clear contrast defects in the delayed phase, not only in the harmonic but also in the conventional mode.