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A. Tsuchiya

Publications and source records attributed to A. Tsuchiya.

13 recordsLinked to original sources

Time-Reversal Symmetry-Breaking Superconductivity in Heavy Fermion PrOs4Sb12 detected by Muon Spin Relaxation

We report on muon spin relaxation measurements of the 4f^2-based heavy-fermion superconductor filled-skutterudite PrOs4Sb12. The results reveal the spontaneous appearance of static internal magnetic fields below the superconducting transition temperature, providing unambiguous evidence for the breaking of time-reversal symmetry in the superconducting state. A discussion is made on which of the spin or orbital component of Cooper pairs carries a nonzero momentum.

cond-mat.supr-con

IIB Matrix Model

We review our proposal for a constructive definition of superstring, type IIB matrix model. The IIB matrix model is a manifestly covariant model for space-time and matter which possesses N=2 supersymmetry in ten dimensions. We refine our arguments to reproduce string perturbation theory based on the loop equations. We emphasize that the space-time is dynamically determined from the eigenvalue distributions of the matrices. We also explain how matter, gauge fields and gravitation appear as fluctuations around dynamically determined space-time.

hep-th

USp(2k) Matrix Model

We review the construction and theoretical implications of the USp(2k) matrix model in zero dimension introduced in ref. \cite{IT1,IT2}. It is argued that the model provides a constructive approach to Type I superstrings and is at the same time dynamical theory of spacetime points. Three subjects are discussed : semiclassical pictures and series of degenerate perturbative vacua associated with the worldvolume representation of the model, the formation of extended (D-)objects from the fermionic integrations via the (non-)abelian Berry phase, and the Schwinger-Dyson/loop equations which exhibit the joining-splitting interactions required. Lectures presented at the 13th Nishinomiya-Yukawa Memorial Symposium ``Dynamics of Fields and Strings'' (November 12-13,1998) and at the YITP workshop (November 16-18, 1998).

hep-th

USp(2k) Matrix Model: Schwinger-Dyson Equations and Closed-Open String Interactions

We derive the Schwinger-Dyson/loop equations for the USp(2k) matrix model which close among the closed and open Wilson loop variables. These loop equations exhibit a complete set of the joining and splitting interactions required for the nonorientable Type I superstrings. The open loops realize the SO(2n_f) Chan-Paton factor and their linearized loop equations derive the mixed Dirichlet/Neumann boundary conditions.

hep-th

Dynamical Properties of Large N Reduced Model of Yang-Mills Theory

We study the large N reduced model of D-dimensional Yang-Mills theory with special attention to the dynamical aspects related to the eigenvalues of the NxN matrices, which correspond to the space-time coordinates in the IIB matrix model. We define a quantity which represents the uncertainty of the space-time coordinates and show that it is of the same order as the extent of the space time, which means that the classical space-time picture is maximally broken. The absence of the SSB of the Lorentz invariance is also shown.

hep-lat

Degenerate Double Affine Hecke Algebra And Conformal Field Theory

We introduce a class of induced representations of the degenerate double affine Hecke algebra of gl_N and analyze their structure mainly by means of intertwiners. We also construct them from modules of the affine Lie algebra using Knizhnik-Zamolodchikov connections in the conformal field theory. This construction provides a natural quotient of induced modules, which turns out to be the unique irreducible one under a certain condition. Some cunjectual formulas are presented for the symmetric part of these quotients.

q-alg

Exact Results in N_c=2 IIB Matrix Model

We investigate N_c=2 case of IIB matrix model, which is exactly soluble. We calculate the partition function exactly and obtain a finite result without introducing any cut-off. We also evaluate some correlation functions consisting of Wilson loops.

hep-th

String Field Theory from IIB Matrix Model

We derive Schwinger-Dyson equations for the Wilson loops of a type IIB matrix model. Superstring coordinates are introduced through the construction of the loop space. We show that the continuum limit of the loop equation reproduces the light-cone superstring field theory of type IIB superstring in the large-N limit. We find that the interacting string theory can be obtained in the double scaling limit as it is expected.

hep-th

A Large-N Reduced Model as Superstring

A matrix model which has the manifest ten-dimensional N=2 super Poincare invariance is proposed. Interactions between BPS-saturated states are analyzed to show that massless spectrum is the same as that of type IIB string theory. It is conjectured that the large-N reduced model of ten-dimensional super Yang-Mills theory can be regarded as a constructive definition of this model and therefore is equivalent to superstring theory.

hep-th

Operator Product Expansion in Two-Dimensional Quantum Gravity

We consider correlation functions of operators and the operator product expansion in two-dimensional quantum gravity. First we introduce correlation functions with geodesic distances between operators kept fixed. Next by making two of the operators closer, we examine if there exists an analog of the operator product expansion in ordinary field theories. Our results suggest that the operator product expansion holds in quantum gravity as well, though special care should be taken regarding the physical meaning of fixing geodesic distances on a fluctuating geometry.

hep-th

A Unified Approach to Solvable Models of Dilaton Gravity in Two-Dimensions Based on Symmetry

A large class of solvable models of dilaton gravity in two space-time dimensions, capable of describing black hole geometry, are analyzed in a unified way as non-linear sigma models possessing a special symmetry. This symmetry, which can be neatly formulated in the target-space-covariant manner, allows one to decompose the non-linearly interacting dilaton-gravity system into a free field and a field satisfying the Liouville equation with in general non-vanishing cosmological term. In this formulation, all the existent models are shown to fall into the category with vanishing cosmological constant. General analysis of the space-time structureinduced by a matter shock wave is performed and new models, with and without the cosmological term, are discussed.

hep-th

Quantum Gravity and Black Hole Dynamics in 1+1 Dimensions

We study the quantum theory of 1+1 dimensional dilaton gravity, which is an interesting toy model of the black hole dynamics. The functional measures are explicitly evaluated and the physical state conditions corresponding to the Hamiltonian and the momentum constraints are derived. It is pointed out that the constraints form the Virasoro algebra without central charge. In ADM formalism the measures are very ambiguous, but in our formalism they are explicitly defined. Then the new features which are not seen in ADM formalism come out. A singularity appears at $\df^2 =κ(>0) $, where $κ=(N-51/2)/12 $ and $ N$ is the number of matter fields. Behind the singularity the quantum mechanical region $κ> \df^2 >0 $ extends, where the sign of the kinetic term in the Hamiltonian constraint changes. If $κ<0 $, the singularity disappears. We discuss the quantum dynamics of black hole and then give a suggestion for the resolution of the information loss paradox. We also argue the quantization of the spherically symmetric gravitational system in 3+1 dimensions. In appendix the differences between the other quantum dilaton gravities and ours are clarified and our status is stressed.

hep-th