61,732 research outputs found
Chiral symmetry breaking and topology for all N
We investigate spontaneous chiral symmetry breaking in SU(N) gauge theories
at large N using overlap fermions. The exact zero modes and the low-lying modes
of the Dirac operator provide the tools to gain insight into the interplay
between chiral symmetry breaking and topology. We find that topology indeed
drives chiral symmetry breaking at N=3 as well as at large N. By comparing the
results on various volumes and at different lattice spacings we are able to
show that our conclusions are not affected by finite volume effects and also
hold in the continuum limit. We then address the question whether the topology
can be usefully described in terms of instantons.Comment: Talk at Lattice 2003 (chiral); 3 pages, 2 figures, espcrc2.st
Topological Symmetry Breaking on Einstein Manifolds
It is known that if gauge conditions have Gribov zero modes, then topological
symmetry is broken. In this paper we apply it to topological gravity in
dimension . Our choice of the gauge condition for conformal
invariance is , where is the Ricci scalar curvature. We find
when , topological symmetry is not broken, but when
and solutions of the Einstein equations exist then topological symmetry is
broken. This conditions connect to the Yamabe conjecture. Namely negative
constant scalar curvature exist on manifolds of any topology, but existence of
nonnegative constant scalar curvature is restricted by topology. This fact is
easily seen in this theory. Topological symmetry breaking means that BRS
symmetry breaking in cohomological field theory. But it is found that another
BRS symmetry can be defined and physical states are redefined. The divergence
due to the Gribov zero modes is regularized, and the theory after topological
symmetry breaking become semiclassical Einstein gravitational theory under a
special definition of observables.Comment: 16 pages, Late
Curvature and topological effects on dynamical symmetry breaking in a four- and eight-fermion interaction model
A dynamical mechanism for symmetry breaking is investigated under the
circumstances with the finite curvature, finite size and non-trivial topology.
A four- and eight-fermion interaction model is considered as a prototype model
which induces symmetry breaking at GUT era. Evaluating the effective potential
in the leading order of the 1/N-expansion by using the dimensional
regularization, we explicitly calculate the phase boundary which divides the
symmetric and the broken phase in a weakly curved space-time and a flat
space-time with non-trivial topology, .Comment: 20 pages, 21 figure
Exploring Residual Gauge Symmetry Breaking
Simulations of pure-gauge SU(2) lattice gauge theory are performed in the
minimal Coulomb gauge. This leaves a residual or remnant gauge symmetry still
active which is global in three directions but still local in one. Using
averaged fourth-dimension pointing links as a spin-like order parameter, the
remnant symmetry appears to undergo spontaneous symmetry breaking at around
. Both the Binder cumulant and the magnetization itself exhibit
crossings in this region using lattices up to , and a susceptibility peak
is also observed. Finite size scaling indicates a weak first-order transition.
The symmetry breaking is also observed to take place in the fundamental-adjoint
plane, and is coincident with the strong first-order transition that exists
there at large . This provides confirmation that this
phase transition is a symmetry-breaking transition. A well-known theorem
concerning the instantaneous Coulomb potential has previously proven that a
transition where such a Coulomb-gauge remnant symmetry breaks is necessarily
deconfining.Comment: 7 pages, 4 figures (6 figure files), PoS style, Lattice 2006
Poster(Topology and Confinement
Higgs as an indication for flavor symmetry
Lepton flavor violating Higgs decays can arise in flavor symmetry models
where the Higgs sector is responsible for both the electroweak and the flavor
symmetry breaking. Here we advocate an three-Higgs-doublet model where
tightly constrained flavor changing neutral currents are suppressed by a
remnant symmetry. A small breaking of this symmetry can explain the
excess of Higgs decay final states with a topology
reported recently by CMS if the new neutral scalars are light. The model also
predicts sizable rates for lepton flavor violating Higgs decays in the
and channels because of the unifying flavor symmetry.Comment: 15+9 pages, 7 figures, updated for publication in PR
- …