1,083 research outputs found
Finite size effects at phase transition in compact U(1) gauge theory
We present and discuss the results of a Monte-Carlo simulation of the phase
transition in pure compact U(1) lattice gauge theory with Wilson action on a
hypercubic lattice with periodic boundary conditions. The statistics are large
enough to make a thorough analysis of the size dependence of the gap. In
particular we find a non-zero latent heat in the infinite volume limit. We also
find that the critical exponents and are consistent with the
hyperscaling relation but confirm that the critical behavior is different from
a conventional first-order transition.Comment: Talk presented at Lattice '97; 3 pages, Latex fil
Critical behaviour of SU(2) lattice gauge theory. A complete analysis with the -method
We determine the critical point and the ratios and
of critical exponents of the deconfinement transition in gauge theory
by applying the -method to Monte Carlo data of the modulus and the
square of the Polyakov loop. With the same technique we find from the Binder
cumulant its universal value at the critical point in the thermodynamical
limit to and for the next-to-leading exponent .
From the derivatives of the Polyakov loop dependent quantities we estimate then
. The result from the derivative of is , in
complete agreement with that of the Ising model.Comment: 11 pages, 3 Postscript figures, uses Plain Te
Non-perturbative determination of anisotropy coefficients and pressure gap at the deconfining transition of QCD
We propose a new non-perturbative method to compute derivatives of gauge
coupling constants with respect to anisotropic lattice spacings (anisotropy
coefficients). Our method is based on a precise measurement of the finite
temperature deconfining transition curve in the lattice coupling parameter
space extended to anisotropic lattices by applying the spectral density method.
We determine the anisotropy coefficients for the cases of SU(2) and SU(3) gauge
theories. A longstanding problem, when one uses the perturbative anisotropy
coefficients, is a non-vanishing pressure gap at the deconfining transition
point in the SU(3) gauge theory. Using our non-perturbative anisotropy
coefficients, we find that this problem is completely resolved.Comment: LATTICE98(hightemp
Atomization and mixing study
The state of the art in atomization and mixing for triplet, pentad, and coaxial injectors is described. Injectors that are applicable for LOX/hydrocarbon propellants and main chamber and fuel rich preburner/gas generator mixture ratios are of special interest. Various applicable correlating equations and parameters as well as test data found in the literature are presented. The validity, utility, and important aspects of these data and correlations are discussed and the measurement techniques used are evaluated. Propellant mixing tests performed are described and summarized, results are reported, and tentative conclusions are included
Strong Coupling Lattice Schwinger Model on Large Spherelike Lattices
The lattice regularized Schwinger model for one fermion flavor and in the
strong coupling limit is studied through its equivalent representation as a
restricted 8-vertex model. The Monte Carlo simulation on lattices with
torus-topology is handicapped by a severe non-ergodicity of the updating
algorithm; introducing lattices with spherelike topology avoids this problem.
We present a large scale study leading to the identification of a critical
point with critical exponent , in the universality class of the Ising
model or, equivalently, the lattice model of free fermions.Comment: 16 pages + 7 figures, gzipped POSTSCRIPT fil
Finite-Size Scaling Study of the Three-Dimensional Classical Heisenberg Model
We use the single-cluster Monte Carlo update algorithm to simulate the
three-dimensional classical Heisenberg model in the critical region on simple
cubic lattices of size with , and . By
means of finite-size scaling analyses we compute high-precision estimates of
the critical temperature and the critical exponents, using extensively
histogram reweighting and optimization techniques. Measurements of the
autocorrelation time show the expected reduction of critical slowing down at
the phase transition. This allows simulations on significantly larger lattices
than in previous studies and consequently a better control over systematic
errors in finite-size scaling analyses.Comment: 9 pages, FUB-HEP 9/92, HLRZ Preprint 56/92, August 199
Generalized-ensemble simulations of spin systems and protein systems
In complex systems such as spin systems and protein systems, conventional
simulations in the canonical ensemble will get trapped in states of energy
local minima. We employ the generalized-ensemble algorithms in order to
overcome this multiple-minima problem. Three well-known generalized-ensemble
algorithms, namely, multicanonical algorithm, simulated tempering, and
replica-exchange method, are described. We then present three new
generalized-ensemble algorithms based on the combinations of the three methods.
Effectiveness of the new methods are tested with a Potts model and protein
systems.Comment: 12 pages, (LaTeX2e), 6 figures, Computer Physics Communications, in
pres
- …