16 research outputs found
Strongly coupled U(1) lattice gauge theory as a microscopic model of Yukawa theory
Dynamical chiral symmetry breaking in a strongly coupled U(1) lattice gauge
model with charged fermions and scalar is investigated by numerical simulation.
Several composite neutral states are observed, in particular a massive fermion.
In the vicinity of the tricritical point of this model we study the effective
Yukawa coupling between this fermion and the Goldstone boson. The perturbative
triviality bound of Yukawa models is nearly saturated. The theory is quite
similar to strongly coupled Yukawa models for sufficiently large coupling
except the occurrence of an additional state -- a gauge ball of mass about half
the mass of the fermion.Comment: 4 page
Two-dimensional model of dynamical fermion mass generation in strongly coupled gauge theories
We generalize the Schwinger model on the lattice by adding a charged
scalar field. In this so-called model the scalar field shields
the fermion charge, and a neutral fermion, acquiring mass dynamically, is
present in the spectrum. We study numerically the mass of this fermion at
various large fixed values of the gauge coupling by varying the effective
four-fermion coupling, and find an indication that its scaling behavior is the
same as that of the fermion mass in the chiral Gross-Neveu model. This suggests
that the model is in the same universality class as the
Gross-Neveu model, and thus renormalizable and asymptotic free at arbitrary
strong gauge coupling.Comment: 18 pages, LaTeX2e, requires packages rotating.sty and curves.sty from
CTA
Dynamical fermion mass generation at a tricritical point in strongly coupled U(1) lattice gauge theory
Fermion mass generation in the strongly coupled U(1) lattice gauge theory
with fermion and scalar fields of equal charge is investigated by means of
numerical simulation with dynamical fermions. Chiral symmetry of this model is
broken by the gauge interaction and restored by the light scalar. We present
evidence for the existence of a particular, tricritical point of the
corresponding phase boundary where the continuum limit might possibly be
constructed. It is of interest as a model for dynamical symmetry breaking and
mass generation due to a strong gauge interaction. In addition to the massive
and unconfined fermion F and Goldstone boson , a gauge ball of mass and some other states are found. Tricritical exponents appear
to be non-classical.Comment: 21 page
Chiral transition and monopole percolation in lattice scalar QED with quenched fermions
We study the interplay between topological observables and chiral and Higgs
transitions in lattice scalar QED with quenched fermions. Emphasis is put on
the chiral transition line and magnetic monopole percolation at strong gauge
coupling. We confirm that at infinite gauge coupling the chiral transition is
described by mean field exponents. We find a rich and complicated behaviour at
the endpoint of the Higgs transition line which hampers a satisfactory analysis
of the chiral transition. We study in detail an intermediate coupling, where
the data are consistent both with a trivial chiral transition clearly separated
from monopole percolation and with a chiral transition coincident with monopole
percolation, and characterized by the same critical exponent .
We discuss the relevance (or lack thereof) of these quenched results to our
understanding of the \chupiv\ model. We comment on the interplay of magnetic
monopoles and fermion dynamics in more general contexts.Comment: 29 pages, 13 figures included, LaTeX2e (elsart
Critical Behavior of the Schwinger Model with Wilson Fermions
We present a detailed analysis, in the framework of the MFA approach, of the
critical behaviour of the lattice Schwinger model with Wilson fermions on
lattices up to , through the study of the Lee-Yang zeros and the specific
heat. We find compelling evidence for a critical line ending at
at large . Finite size scaling analysis on lattices and indicates a continuous transition. The hyperscaling relation
is verified in the explored region.Comment: 12 pages LaTeX file, 10 figures in one uuencoded compressed
postscript file. Report LNF-95/049(P