3,388 research outputs found
Simplicial Chiral Models
Principal chiral models on a d-1 dimensional simplex are introduced and
studied analytically in the large limit. The and
models are explicitly solved. Relationship with standard lattice models and
with few-matrix systems in the double scaling limit are discussed.Comment: 6 pages, PHYZZ
Idealized Multigrid Algorithm for Staggered Fermions
An idealized multigrid algorithm for the computation of propagators of
staggered fermions is investigated.
Exemplified in four-dimensional gauge fields, it is shown that the
idealized algorithm preserves criticality under coarsening.
The same is not true when the coarse grid operator is defined by the Galerkin
prescription.
Relaxation times in computations of propagators are small, and critical
slowing is strongly reduced (or eliminated) in the idealized algorithm.
Unfortunately, this algorithm is not practical for production runs, but the
investigations presented here answer important questions of principle.Comment: 11 pages, no figures, DESY 93-046; can be formatted with plain LaTeX
article styl
Hybrid Monte Carlo Simulation of Graphene on the Hexagonal Lattice
We present a method for direct hybrid Monte Carlo simulation of graphene on
the hexagonal lattice. We compare the results of the simulation with exact
results for a unit hexagonal cell system, where the Hamiltonian can be solved
analytically.Comment: 5 pages, 4 figure
Green's Functions from Quantum Cluster Algorithms
We show that cluster algorithms for quantum models have a meaning independent
of the basis chosen to construct them. Using this idea, we propose a new method
for measuring with little effort a whole class of Green's functions, once a
cluster algorithm for the partition function has been constructed. To explain
the idea, we consider the quantum XY model and compute its two point Green's
function in various ways, showing that all of them are equivalent. We also
provide numerical evidence confirming the analytic arguments. Similar
techniques are applicable to other models. In particular, in the recently
constructed quantum link models, the new technique allows us to construct
improved estimators for Wilson loops and may lead to a very precise
determination of the glueball spectrum.Comment: 15 pages, LaTeX, with four figures. Added preprint numbe
Representation of the Human Musculature in the Bronze Age Aegean
Bronze Age sculptures range from abstract to realistic, but how accurate are the realistic sculptures? To answer this question, it is useful to compare three pieces of artwork: Prince of Lilies from Knossos, Kouros from Palaikastro, and the Boxer Rhyta from Ayia Triadha to a musculature replica. These pieces originate from the Bronze Age in the Aegean. What this comparison will tell us is how much the ancient peoples were studying the human body, along with the reasons as to why these sculptures were portrayed with such realistic characteristics. To accomplish this goal this paper takes the artifacts background into consideration, while measuring the length of several muscle groups and comparing them to an anatomical representation.
The results showed varied accuracy with how the artifacts compare to anatomical models. One of the artifacts is shown to be almost identical to the anatomical replica. Other conclusions involve the backgrounds of the sculptures which range from religious reasons to possible images of royalty. Each provides insight into the life of the Bronze Age Aegean. In addition, a further study into the Prince of Lilies from Knossos, showed that the artifact was reconstructed, and that there are some controversies surrounding the reconstruction
Spin-String Interaction in QCD Strings
I consider the question of the interaction between a QCD string and the spin
of a quark or an antiquark on whose worldline the string terminates. The
problem is analysed from the point of view of a string representation for the
expectation value of a Wilson loop for a spin-half particle. A string
representation of the super Wilson loop is obtained starting from an effective
string representation of a Wilson Loop. The action obtained in this manner is
invariant under a worldline supersymmetry and has a boundary term which
contains the spin-string interaction. For rectangular loops the spin-string
interaction vanishes and there is no spin-spin term in the resulting heavy
quark potential. On the other hand if an allowance is made for the finite
intrinsic thickness of the flux-tube, by assuming that the spin-string
interaction takes place not just at the boundary of the string world-sheet but
extends to a distance of the order of the intrinsic thickness of the flux tube,
then we do obtain a spin-spin interaction which falls as the fifth power of the
distance. Such a term was previously suggested by Kogut and Parisi in the
context of a flux-tube model of confinement.Comment: 19 pages, 1 figure; Published version with added discussion and
references in section
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