arXiv subjects

T. Fujiwara

Publications and source records attributed to T. Fujiwara.

49 records · Page 3Linked to original sources

arXiv1998

Quantum Exchange Algebra and Exact Operator Solution of $A_2$-Toda Field Theory

Locality is analyzed for Toda field theories by noting novel chiral description in the conventional nonchiral formalism. It is shown that the canonicity of the interacting to free field mapping described by the classical solution is automatically guaranteed by the locality. Quantum Toda theories are investigated by applying the method of free field quantization. We give Toda exponential operators associated with fundamental weight vectors as bilinear forms of chiral fields satisfying characteristic quantum exchange algebra. It is shown that the locality leads to nontrivial relations among the ${\cal R}$-matrix and the expansion coefficients of the exponential operators. The Toda exponentials are obtained for $A_2$-system by extending the algebraic method developed for Liouville theory. The canonical commutation relations and the operatorial field equations are also examined.

hep-th↗

arXiv1998

Fermi surfaces and anomalous transport in quasicrystals

Fermi surfaces of several quasicrystalline approximants are calculated by means of ab-initio methods which enable direct comparison with dHvA experiments. A criterion for anomalous metallic transport is proposed and power-law temperature dependence of electronic conductivity is deduced from scaling analysis of the Kubo formula.

cond-mat.mtrl-sci↗

arXiv1998

Exact Operator Solution of $A_2$-Toda Field Theory

Quantum $A_2$-Toda field theory in two dimensions is investigated based on the method of quantizing canonical free field. Toda exponential operators associated with the fundamental weights are constructed to the fourth order in the cosmological constant. This leads us to a conjecture for the exact operator solution.

hep-th↗

arXiv1997

On the Three-Point Couplings in Toda Field Theory

Correlation functions of Toda field vertices are investigated by applying the method of integrating zero-mode developed for Liouville theory. We generalize the relations among the zero-, two- and three-point couplings known in Liouville case to arbitrary Toda theories. Two- and three-point functions of Toda vertices associated with the simple roots are obtained.

hep-th↗

arXiv1997

Exact Operator Solution for Liouville Theory with $q$ A Root of Unity

The exact operator solution for quantum Liouville theory constructed for the generic quantum deformation parameter $q$ is extended to the case with $q$ being a root of unity. The screening charge operator becomes nilpotent in such cases and arbitrary Liouville exponentials can be obtained in finite polynomials of the screening charge.

hep-th↗

arXiv1996

Quantum Exchange Algebra and Locality in Liouville Theory

Exact operator solution for quantum Liouville theory is investigated based on the canonical free field. Locality, the field equation and the canonical commutation relations are examined based on the exchange algebra hidden in the theory. The exact solution proposed by Otto and Weigt is shown to be correct to all order in the cosmological constant.

hep-th↗

arXiv1996

Growth of Velocity Dispersions for Collapsing Spherical Stellar Systems

First, we have ensured that spherical nonrotating collisionless systems collapse with almost retaining spherical configurations during initial contraction phases even if they are allowed to collapse three-dimensionally. Next, on the assumption of spherical symmetry, we examine the evolution of velocity dispersions with collapse for the systems which have uniform or power-law density profiles with Maxwellian velocity distributions by integrating the collisionless Boltzmann equation directly. The results show that as far as the initial contraction phases are concerned, the radial velocity dispersion never grows faster than the tangential velocity dispersion except at small radii where the nearly isothermal nature remains, irrespective of the density profiles and virial ratios. This implies that velocity anisotropy as an initial condition should be a poor indicator for the radial orbit instability. The growing behavior of the velocity dispersions is briefly discussed from the viewpoint that phase space density is conserved in collisionless systems.

astro-ph↗

arXiv1995

BFV-BRST Quantization of 2D Supergravity

Two-dimensional supergravity theory is quantized as an anomalous gauge theory. In the Batalin-Fradkin (BF) formalism, the anomaly-canceling super-Liouville fields are introduced to identify the original second-class constrained system with a gauge-fixed version of a first-class system. The BFV-BRST quantization applies to formulate the theory in the most general class of gauges. A local effective action constructed in the configuration space contains two super-Liouville actions; one is a noncovariant but local functional written only in terms of 2D supergravity fields, and the other contains the super-Liouville fields canceling the super-Weyl anomaly. Auxiliary fields for the Liouville and the gravity super-multiplets are introduced to make the BRST algebra close off-shell. Inclusion of them turns out to be essentially important especially in the super-lightcone gauge-fixing, where the super-curvature equations ($\dl^3_-g_{++} =\dl^2_-χ_{++}=0$) are obtained as a result of BRST invariance of the theory. Our approach reveals the origin of the graded-SL(2,R) current algebra symmetry in a transparent manner.

hep-th↗

arXiv1994

New insight into BRST anomalies in superstring theory

Based on the extended BRST formalism of Batalin, Fradkin and Vilkovisky, we perform a general algebraic analysis of the BRST anomalies in superstring theory of Neveu-Schwarz-Ramond. Consistency conditions on the BRST anomalies are completely solved. The genuine super-Virasoro anomaly is identified with the essentially unique solution to the consistency condition without any reference to a particular gauge for the 2D supergravity fields. In a configuration space where metric and gravitino fields are properly constructed, general form of the super-Weyl anomaly is obtained from the super-Virasoro anomaly as its descendant. We give a novel local action of super-Liouville type, which plays a role of Wess-Zumino-Witten term shifting the super-Virasoro anomaly into the super-Weyl anomaly. These results reveal a hierarchial relationship in the BRST anoamlies.

hep-th↗

arXiv1993

Gauge Equivalence in Two--Dimensional Gravity

Two-dimensional quantum gravity is identified as a second-class system which we convert into a first-class system via the Batalin-Fradkin (BF) procedure. Using the extended phase space method, we then formulate the theory in most general class of gauges. The conformal gauge action suggested by David, Distler and Kawai is derived from a first principle. We find a local, light-cone gauge action whose Becchi-Rouet-Stora-Tyutin invariance implies Polyakov's curvature equation $\partial_{-}R=\partial_{-}^{3}g_{++}=0$, revealing the origin of the $SL(2,R)$ Kac-Moody symmetry. The BF degree of freedom turns out be dynamically active as the Liouville mode in the conformal gauge, while in the light-cone gauge the conformal degree of freedom plays that r{ô}le. The inclusion of the cosmological constant term in both gauges and the harmonic gauge-fixing are also considered.

hep-th↗

arXiv1993

Unrecognizable Black Holes in Two Dimensions

The classical 2D cosmological model of Callan, Giddings, Harvey and Strominger possesses a global symmetry that is responsible for decoupling of matter fields. The model is quantized on the basis of the extended phase space method to allow an exhaustive, algebraic analysis to find potential anomalies. Under a certain set of reasonable assumptions we show that neither the BRST symmetry of the theory nor the global symmetry suffers from an anomaly. From this we conclude that there is nothing to recognize the existence of black hole and therefore nothing to radiate in their cosmological model.

hep-th↗

arXiv1993

Canonical treatment of two dimensional gravity as an anomalous gauge theory

The extended phase space method of Batalin, Fradkin and Vilkovisky is applied to formulate two dimensional gravity in a general class of gauges. A BRST formulation of the light-cone gauge is presented to reveal the relationship between the BRST symmetry and the origin of $SL(2,R)$ current algebra. From the same principle we derive the conformal gauge action suggested by David, Distler and Kawai.

hep-th↗

arXiv1992

A new insight into BRST anomalies in string theory

Using the generalized hamiltonian method of Batalin, Fradkin and Vilkovisky, we investigate the algebraic structure of anomalies in the Polyakov string theory that appear as the Schwinger terms in super-commutation relations between BRST charge and total hamiltonian. We obtain the most general form of the anomalies in the extended phase space, without any reference to a two dimensional metric. This pregeometri- cal result, refered to as the genelarized Virasoro anomaly, independent of the gauge and the regularization under a minor assumption, is a non-perturbative result, and valid for any space-time dimension. In a configuration space, in which the two dimensional metric can be identified, we can geometrize the result without assuming the weak gravitational field, showing that the most general anomaly exactly exhibits the Weyl anomaly.

hep-th↗