Yoshinori Matsuo

Viscosity bound, causality violation and instability with stringy correction and charge

Recently, it has been shown that if we consider the higher derivative correction, the viscosity bound conjectured to be ?/s = 1/4? is violated and so is the causality. In this paper, we consider medium effect and the higher derivative correction simultaneously by adding charge and Gauss-Bonnet terms. We find that the viscosity bound violation is not changed by the charge. However, we find that two effects together create another instability for large momentum regime. We argue the presence of tachyonic modes and show it numerically. We draw a phase diagram relevant to the instability in charge-coupling space.

Another realization of Kerr/CFT correspondence

Abstract We study another realization of the Kerr/CFT correspondence. By imposing new asymptotic conditions for the near-horizon geometry of Kerr black hole, an asymptotic symmetry which contains all of the exact isometries can be obtained. In particular, the Virasoro algebra can be realized as an enhancement of SL ( 2 , R ) symmetry of the AdS geometry. By using this asymptotic symmetry, we discuss finite temperature effects and show the correspondence concretely.

Loops versus matrices: The Nonperturbative aspects of noncritical string

The nonperturbative aspects of string theory are explored for non-critical string in two distinct formulations, loop equations and matrix models. The effects corresponding to the D-brane in these formulations are especially investigated in detail. It is shown that matrix models can universally yield a definite value of the chemical potential for an instanton while loop equations cannot. This implies that it may not be possible to formulate string theory nonperturbatively solely in terms of closed strings.

Extended Conformal Algebras With

Abstract Extended conformal algebras with supersymmetry (super-Wn algebra) is constructed and the algebras are shown to exist for special values of the central charge c. The super-Wn algebra containing currents of spin ( 5 2 , 3) has a unitary representation (c = 10 7 ) and a non-unitary one (c = − 5 2 ) , and the super-Wn algebra containing currents of spins (2, 5 2 ) has a non-unitary representation (c = − 6 5 ) .

N=1

We study the transport coefficients of Quark-Gluon-Plasma in finite temperature and finite baryon density. We consider AdS/QCD of charged AdS black hole background with bulk-filling branes identifying the U (1) charge as the baryon number. Using Reissner

Supersymmetry

The correspondence between the Kerr black hole and a boundary CFT has been conjectured recently. The conjecture has been proposed first only for the half of the CFT, namely for left movers. For right movers, the correspondence has been also found out through the suitable asymptotic boundary condition. However, the boundary conditions for these two studies are exclusive to each other. The boundary condition for left movers does not allow the symmetry of right movers, and vice versa. We propose a new boundary condition which allows both left and right movers. The isometries U(1) for the left mover and the for right mover are enhanced to Virasoro algebras with and without central extensions, respectively.

Density Dependence of Transport Coefficients from Holographic Hydrodynamics

Using the Eguchi-Kawai equivalence, we provide regularizations of supersymmetric quiver and Chern-Simons gauge theories which leave the supersymmetries unbroken. This allow us to study many interesting theories on a computer. As examples we construct large-N reduced models of supersymmetric QCD with flavor and the ABJM model of multiple M2 branes.

Yet another realization of Kerr/CFT correspondence

We study the effects of the Chern-Simons term in the hydrodynamics of the five-dimensional Reissner-Nordstr¨om-AdS background. We work out the decoupling problem of the equations of motion and calculate the retarded Green functions explicitly. We then find that the Chern-Simons term induces the magnetic conductivity caused by the anomaly effect. It is increasing function of temperature running from a non-zero value at zero temperature to the twice the value at infinite temperature.

Large-N reduced models of supersymmetric quiver, Chern-Simons gauge theories and ABJM

Abstract We apply the Kerr/CFT correspondence to the rotating black p-brane solutions. These solutions give the simplest examples from string theory point of view. Their near horizon geometries have structures of AdS, even though black p-brane solutions do not have AdS-like structures in the non-rotating case. The microscopic entropy which can be calculated via the Cardy formula exactly agrees with Bekenstein–Hawking entropy.

Chern-Simons term in holographic hydrodynamics of charged AdS black hole

Abstract In the previous paper we studied the transport coefficients of quark–gluon plasma in finite temperature and finite density in vector and tensor modes. In this paper, we extend it to the scalar modes. We work out the decoupling problem and hydrodynamic analysis for the sound mode in charged AdS black hole and calculate the sound velocity, the charge susceptibility and the electrical conductivity. We find that Einstein relation among the conductivity, the diffusion constant and the susceptibility holds exactly.