Complex structure of a DT surface with T2T^2 topology

A method of defining the complex structure(moduli) for dynamically triangulated(DT) surfaces with torus topology is proposed. Distribution of the moduli parameter is measured numerically and compared with the Liouville theory for the surface coupled to c = 0, 1 and 2 matter. Equivalence between the dynamical triangulation and the Liouville theory is established in terms of the complex structure.Comment: 3 pages, 5 ps-figures, espcrc2.sty included. Talk presented at LATTICE96(gravity

Grand-canonical simulation of two-dimensional simplicial gravity

The string susceptibility exponents of dynamically triangulated 2-dimensional surfaces with various topologies, such as a sphere, torus and double-torus, were calculated by the grand-canonical Monte Carlo method. These simulations were made for surfaces coupled to $d$-Ising spins ($d$=0,1,2,3,5). In each simulation the area of surface was constrained to within 1000 to 3000 of triangles, while maintaining the detailed-balance condition. The numerical results show excellent agreement with theoretical predictions as long as $d \leq 2$.Comment: 9 pages, Latex include 5 postscript figures, using psfig.sty and cite.st

One-Dimensional Quantum Transport Affected by a Background Medium: Fluctuations versus Correlations

We analyze the spectral properties of a very general two-channel fermion-boson transport model in the insulating and metallic regimes, and the signatures of the metal-insulator quantum phase transition in between. To this end we determine the single particle spectral function related to angle-resolved photoemission spectroscopy, the momentum distribution function, the Drude weight and the optical response by means of a dynamical (pseudo-site) density-matrix renormalization group technique for the one-dimensional half-filled band case. We show how the interplay of correlations and fluctuations in the background medium controls the charge dynamics of the system, which is a fundamental problem in a great variety of advanced materials.Comment: 6 pages, 5 figures, final versio

Topology of Boundary Surfaces in 3D Simplicial Gravity

A model of simplicial quantum gravity in three dimensions(3D) was investigated numerically based on the technique of dynamical triangulation (DT). We are concerned with the genus of surfaces appearing on boundaries (i.e., sections) of a 3D DT manifold with $S^{3}$ topology. Evidence of a scaling behavior of the genus distributions of boundary surfaces has been found.Comment: 3 pages, latex, 4 ps figures, uses espcrc2.sty. Talk presented at LATTICE'97(gravity

Scaling Structures in Four-dimensional Simplicial Gravity

Four-dimensional(4D) spacetime structures are investigated using the concept of the geodesic distance in the simplicial quantum gravity. On the analogy of the loop length distribution in 2D case, the scaling relations of the boundary volume distribution in 4D are discussed in various coupling regions i.e. strong-coupling phase, critical point and weak-coupling phase. In each phase the different scaling relations are found.Comment: 4 pages, latex, 4 ps figures, uses espcrc2.sty. Talk presented at LATTICE96(gravity). All figures and its captions have been improve

Random Surfaces in Three-Dimensional Simplicial Gravity

A model of simplicial quantum gravity in three dimensions is investigated numerically based on the technique of the dynamical triangulation (DT). We are concerned with the surfaces appearing on boundaries (i.e., sections) of three-dimensional DT manifold with $S^{3}$ topology. A new scaling behavior of genus distributions of boundary surfaces is found.Furthermore, these surfaces are compared with the random surfaces generated by the two-dimensional DT method which are well known as a correct discretized method of the two-dimensional quantum gravity.Comment: 12 pages, Latex, 7 Postscript figures, uses psfig.sty and cite.st