arXiv subjects

Yoshinori Matsuo

Publications and source records attributed to Yoshinori Matsuo.

54 records · Page 3Linked to original sources

arXiv2011

Mixed RG Flows and Hydrodynamics at Finite Holographic Screen

We consider quark-gluon plasma with chemical potential and study renormalization group flows of transport coefficients in the framework of gauge/gravity duality. We first study them using the flow equations and compare the results with hydrodynamic results by calculating the Green functions on the arbitrary slice. Two results match exactly. Transport coefficients at arbitrary scale is ontained by calculating hydrodynamics Green functions. When either momentum or charge vanishes, transport coefficients decouple from each other.

hep-th↗

arXiv2010

New Near Horizon Limit in Kerr/CFT

The extremal Kerr black hole with the angular momentum J is conjectured to be dual to CFT with central charges c_L=c_R=12J. However, the central charge in the right sector remains to be explicitly derived so far. In order to investigate this issue, we introduce new near horizon limits of (near) extremal Kerr and five-dimensional Myers-Perry black holes. We obtain Virasoro algebras as asymptotic symmetries and calculate the central charges associated with them. One of them is equivalent to that of the previous studies, and the other is non-zero, but still the order of near extremal parameter. Redefining the algebras to take the standard form, we obtain a finite value as expected by the Kerr/CFT correspondence.

hep-th↗

arXiv2010

Zeta(n) via hyperbolic functions

We present here an approach to a computation of $ζ(2)$ by changing variables in the double integral using hyperbolic trig functions. We also apply this approach to present $ζ(n)$, when $n>2$, as a definite improper integral of single variable.

math.CA↗

arXiv2010

Magnetic conductivity and Chern-Simons Term in Holographic Hydrodynamics of Charged AdS Black Hole

We study the effects of the Chern-Simons term in the hydrodynamics of the five-dimensional Reissner-Nordstrom-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.

hep-th↗

arXiv2010

Quark Number Susceptibility with Finite Chemical Potential in Holographic QCD

We study the quark number susceptibility in holographic QCD with a finite chemical potential or under an external magnetic field at finite temperature. We first consider the quark number susceptibility with the chemical potential. We observe that approaching the critical temperature from high temperature regime, the quark number susceptibility divided by temperature square develops a peak as we increase the chemical potential, which confirms recent lattice QCD results. We discuss this behavior in connection with the existence of the critical end point in the QCD phase diagram. We also consider the quark number susceptibility under the external magnetic field. We predict that the quark number susceptibility exhibits a blow-up behavior at low temperature as we raise the value of the magnetic field. We finally spell out some limitations of our study.

hep-th↗

arXiv2009

Four-dimensional N=1 super Yang-Mills from matrix model

We consider a supersymmetric matrix quantum mechanics. This is obtained by adding Myers and mass terms to the dimensional reduction of 4d N=1 super Yang-Mills theory to one dimension. Using this model we construct 4d N=1 super Yang-Mills theory in the planar limit by using the Eguchi-Kawai equivalence. The same matrix quantum mechanics is also used to provide a nonperturbative formulation of 4d N=1 super Yang-Mills theory on noncommutative space.

hep-th↗

arXiv2009

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

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.

hep-th↗

arXiv2009

Yet Another Realization of Kerr/CFT Correspondence

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 new boundary condition which allows both of left and right movers.

hep-th↗

arXiv2009

Another Realization of Kerr/CFT Correspondence

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.

hep-th↗

arXiv2009

Conformal Symmetry for Rotating D-branes

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.

hep-th↗

arXiv2009

Sound Modes in Holographic Hydrodynamics for Charged AdS Black Hole

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.

hep-th↗

arXiv2008

Worldsheet Analysis of Gauge/Gravity Dualities

Gauge/gravity dualities are investigated from the worldsheet point of view. In [arXiv:0706.1163] and [arXiv:0708.2463], a duality between 4d SYM and supergravity on AdS_5xS^5 has been partly explained by using an anisotropic scale invariance of worldsheet theory. In this paper, we refine the argument and generalize it to lower dimensional cases. We show the correspondence between the Wilson loops in (p+1)-d SYM and the minimal surface in the black p-brane background. Although the scale invariance does not exist in these cases, the generalized scale transformation can be utilized. We also find that the energy density of open strings can be related to the ADM mass of the p-brane without relying on this symmetry.

hep-th↗

arXiv2008

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 $η/s=1/4π$ 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. The stability of the black brane requires the Gauss-Bonnet coupling constant $λ$($=2α'/l^2$) to be smaller than 1/24. We draw a phase diagram relevant to the instability in charge-coupling space.

hep-th↗

arXiv2008

Density Dependence of Transport Coefficients from Holographic Hydrodynamics

We study the transport coefficients of Quark-Gluon-Plasma in finite temperature and finite baryon density. We use AdS/QCD of charged AdS black hole background with bulk-filling branes identifying the U(1) charge as the baryon number. We calculate the diffusion constant, the shear viscosity and the thermal conductivity to plot their density and temperature dependences. Hydrodynamic relations between those are shown to hold exactly. The diffusion constant and the shear viscosity are decreasing as a function of density for fixed total energy. For fixed temperature, the fluid becomes less diffusible and more viscous for larger baryon density.

hep-th↗

arXiv2008

D-instanton derivation of multi-fermion F-terms in supersymmetric QCD

We investigate effects of field theory instantons by considering D-instantons in a suitable D3-brane background. In supersymmetric QCD with SU(N_c) gauge group with N_f=N_c flavors, the moduli space of vacua is deformed by instantons. This effect can be described by the chiral interactions which are called multi-fermion F-terms. We derive these chiral interaction terms as D-instanton effects in the presence of D3-branes. For SU(2), the obtained result agrees with the previous result worked out by Beasley and Witten [hep-th/0409149]. We also explicitly work out those for the case of the symplectic gauge group, and show that they describe the deformation of the moduli space.

hep-th↗

arXiv2006

Notes on the algebraic curves in (p,q) minimal string theory

Loop amplitudes in (p,q) minimal string theory are studied in terms of the continuum string field theory based on the free fermion realization of the KP hierarchy. We derive the Schwinger-Dyson equations for FZZT disk amplitudes directly from the W_{1+\infty} constraints in the string field formulation and give explicitly the algebraic curves of disk amplitudes for general backgrounds. We further give annulus amplitudes of FZZT-FZZT, FZZT-ZZ and ZZ-ZZ branes, generalizing our previous D-instanton calculus from the minimal unitary series (p,p+1) to general (p,q) series. We also give a detailed explanation on the equivalence between the Douglas equation and the string field theory based on the KP hierarchy under the W_{1+\infty} constraints.

hep-th↗

arXiv2006

Nonperturbative Effect in c=1 Noncritical String Theory and Penner Model

We derive the effect of instantons in the Penner model. It is known that the free energies of the Penner model and the c=1 noncritical string at self-dual radius agree in a suitable double scaling limit. On the other hand, the instanton in the matrix model describes a nonperturbative effect in the noncritical string theory. We study the correspondence between the instantons in the Penner model and the nonperturbative effect in c=1 noncritical string at self-dual radius.

hep-th↗

arXiv2004

Universality of Nonperturbative Effect in Type 0 String Theory

We derive the nonperturbative effect in type 0B string theory, which is defined by taking the double scaling limit of a one-matrix model with a two-cut eigenvalue distribution. However, the string equation thus derived cannot determine the nonperturbative effect completely, at least without specifying unknown boundary conditions. The nonperturbative contribution to the free energy comes from instantons in such models. We determine by direct computation in the matrix model an overall factor of the instanton contribution, which cannot be determined by the string equation itself. We prove that it is universal in the sense that it is independent of the detailed structure of potentials in the matrix model. It turns out to be a purely imaginary number and therefore can be interpreted as a quantity related to instability of the D-brane in type 0 string theory. We also comment on a relation between our result and boundary conditions for the string equation.

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