25 research outputs found
Two-Point Functions of Four-Dimensional Simplicial Quantum Gravity
We investigate the interaction mechanism of pure quantum gravity in Regge
discretization. We compute volume-volume and link-link correlation functions.
In a preliminary analysis the forces turn out to be of Yukawa type, at least on
our finite lattice being away from the continuum limit.Comment: 3 pages, uuencoded postscript file; Proceedings of the XI
International Symposion on Lattice Field Theory, Dallas, Oct. 199
SU(2) potentials in quantum gravity
We present investigations of the potential between static charges from a
simulation of quantum gravity coupled to an SU(2) gauge field on and simplicial lattices. In the well-defined phase of the
gravity sector where geometrical expectation values are stable, we study the
correlations of Polyakov loops and extract the corresponding potentials between
a source and sink separated by a distance . In the confined phase, the
potential has a linear form while in the deconfined phase, a screened Coulombic
behavior is found. Our results indicate that quantum gravitational effects do
not destroy confinement due to non-abelian gauge fields.Comment: 3 pages, contribution to Lattice 94 conference, uuencoded compressed
postscript fil
Phase diagram of Regge quantum gravity coupled to SU(2) gauge theory
We analyze Regge quantum gravity coupled to SU(2) gauge theory on , and simplicial lattices. It turns out that
the window of the well-defined phase of the gravity sector where geometrical
expectation values are stable extends to negative gravitational couplings as
well as to gauge couplings across the deconfinement phase transition. We study
the string tension from Polyakov loops, compare with the -function of
pure gauge theory and conclude that a physical limit through scaling is
possible.Comment: RevTeX, 14 pages, 5 figures (2 eps, 3 tex), 2 table
Two-Dimensional Lattice Gravity as a Spin System
Quantum gravity is studied in the path integral formulation applying the
Regge calculus. Restricting the quadratic link lengths of the originally
triangular lattice the path integral can be transformed to the partition
function of a spin system with higher couplings on a Kagome lattice. Various
measures acting as external field are considered. Extensions to matter fields
and higher dimensions are discussed.Comment: 3 pages, uuencoded postscript file; Proceedings of the 2nd IMACS
Conference on Computational Physics, St. Louis, Oct. 199
Spins coupled to a -Regge lattice in 4d
We study an Ising spin system coupled to a fluctuating four-dimensional
-Regge lattice and compare with the results of the four-dimensional Ising
model on a regular lattice. Particular emphasis is placed on the phase
transition of the spin system and the associated critical exponents. We present
results from finite-size scaling analyses of extensive Monte Carlo simulations
which are consistent with mean-field predictions.Comment: Lattice2001(surfaces), 3 pages, 2 figure
Ising spins coupled to a four-dimensional discrete Regge skeleton
Regge calculus is a powerful method to approximate a continuous manifold by a
simplicial lattice, keeping the connectivities of the underlying lattice fixed
and taking the edge lengths as degrees of freedom. The discrete Regge model
employed in this work limits the choice of the link lengths to a finite number.
To get more precise insight into the behavior of the four-dimensional discrete
Regge model, we coupled spins to the fluctuating manifolds. We examined the
phase transition of the spin system and the associated critical exponents. The
results are obtained from finite-size scaling analyses of Monte Carlo
simulations. We find consistency with the mean-field theory of the Ising model
on a static four-dimensional lattice.Comment: 19 pages, 7 figure