39 research outputs found
Smooth Non-Abelian Bosonization
We present an extension of ``smooth bosonization'' to the non-Abelian case.
We construct an enlarged theory containing both bosonic and fermionic fields
which exhibits a local chiral gauge symmetry. A gauge fixing function depending
on one real parameter allows us to interpolate smoothly between a purely
fermionic and a purely bosonic representation. The procedure is, in the special
case of bosonization, complementary to the approach based on duality.Comment: LaTeX, 13 pages, CERN--TH-7347/9
Extended instantons generated on the lattice
We have been able to observe directly extended instantons on the lattice,
with a new method that does not require dislocations to measure them, and where
we do not perform cooling. We showed, based on the simple Abelian Higgs model
in dim., that one can extract the instanton and anti-instanton density
and their size, by measuring the topological charge, , on sub-volumes
larger than the instanton sizes, but smaller than the periodic lattice of size
. We are working on the generalization for non-abelian models.Comment: Talk presented at the LATTICE96(topology) ,uuencoded 3 pp in Latex, 1
ps fig., uses espcrc2.sty and epsf to include fi
The Gridded Time of Waiting; or Is Not Aristotle’s Metaphysics; or A Kind of Idealist Trap; or In My Secret Life
Theoretical musings, descriptions, articulations of process, quotations and anecdotes form a constellation of thoughts about the trappings of the grid, ontology, the subject, the window, translation and other things
The Gauged Vector Model in Four-Dimensions: Resolution of an Old Problem?
A calculation of the renormalization group improved effective potential for
the gauged U(N) vector model, coupled to fermions in the fundamental
representation, computed to leading order in 1/N, all orders in the scalar
self-coupling , and lowest order in gauge coupling , with
of order , is presented. It is shown that the theory has two phases, one of
which is asymptotically free, and the other not, where the asymptotically free
phase occurs if , and
. In the asymptotically free phase, the effective
potential behaves qualitatively like the tree-level potential. In the other
phase, the theory exhibits all the difficulties of the ungauged
vector model. Therefore the theory appears to be consistent (only) in the
asymptotically free phase.Comment: Latex, 18 pages plus 3 figures using epsf. Substantially revised to
correct a factor of 2 error in the previous version of equation (2.5b). This
has significant effects on the results. The model has also been revised to
include fermion
Two Moving-Angled 1-Branes with Electric Fields in a Partially Compact Spacetime
In this article we consider two -branes at angle in the presence of the
background electric fields, in a partially compact spacetime. The branes have
motions along a common direction that is perpendicular to both of them. Using
the boundary state formalism, we calculate their interaction amplitude. Some
special cases of this interaction will be studied in detail.Comment: 10 pages, no figure, Late
Extended Superconformal Galilean Symmetry in Chern-Simons Matter Systems
We study the nonrelativistic limit of the supersymmetric Chern-Simons
matter system. We show that in addition to Galilean invariance the model admits
a set of symmetries generated by fermionic charges, which can be interpreted as
an {\it extended Galilean supersymmetry }. The system also possesses a hidden
conformal invariance and then the full group of symmetries is the {\it extended
superconformal Galilean} group. We also show that imposing extended
superconformal Galilean symmetry determines the values of the coupling
constants in such a way that their values in the bosonic sector agree with the
values of Jackiw and Pi for which self-dual equation exist. We finally analyze
the second quantized version of the model and the two-particle sector.Comment: 32 double-spaced page
Wilson Loops in N=4 Supersymmetric Yang--Mills Theory
Perturbative computations of the expectation value of the Wilson loop in N=4
supersymmetric Yang-Mills theory are reported. For the two special cases of a
circular loop and a pair of anti-parallel lines, it is shown that the sum of an
infinite class of ladder-like planar diagrams, when extrapolated to strong
coupling, produces an expectation value characteristic of the results of the
AdS/CFT correspondence, . For the case of
the circular loop, the sum is obtained analytically for all values of the
coupling. In this case, the constant factor in front of also
agrees with the supergravity results. We speculate that the sum of diagrams
without internal vertices is exact and support this conjecture by showing that
the leading corrections to the ladder diagrams cancel identically in four
dimensions. We also show that, for arbitrary smooth loops, the ultraviolet
divergences cancel to order .Comment: 24 pages, LaTeX, uses feynmp, 12 postscript figure
A New Lattice Action for Studying Topological Charge
We propose a new lattice action for non-abelian gauge theories, which will
reduce short-range lattice artifacts in the computation of the topological
susceptibility. The standard Wilson action is replaced by the Wilson action of
a gauge covariant interpolation of the original fields to a finer lattice. If
the latter is fine enough, the action of all configurations with non-zero
topological charge will satisfy the continuum bound. As a simpler example we
consider the -model in two dimensions, where a numerical
analysis of discretized continuum instantons indicates that a finer lattice
with half the lattice spacing of the original is enough to satisfy the
continuum bound.Comment: 12 pages, LateX, 1 figur
Topological effects in QCD and the problem of short-distance singularities
The topological susceptibility and the higher moments of the topological
charge distribution in QCD are expressed through certain n-point functions of
the scalar and pseudo-scalar quark densities at vanishing momenta, which are
free of short-distance singularities. Since the normalization of the
correlation functions is determined by the non-singlet chiral Ward identities,
these formulae provide an unambiguous regularization-independent definition of
the moments and thus of the charge distribution.Comment: Plain TeX source, 10 pages, reference added, version published in PL
Self-Dual Chern-Simons Solitons in (2+1)-Dimensional Einstein Gravity
We consider here a generalization of the Abelian Higgs model in curved space,
by adding a Chern--Simons term. The static equations are self-dual provided we
choose a suitable potential. The solutions give a self-dual
Maxwell--Chern--Simons soliton that possesses a mass and a spin