7,726 research outputs found
The A-decomposability of the Singer construction
Let denote the Singer construction on an unstable module over the
Steenrod algebra at the prime two; is canonically a subobject of
, where is the polynomial algebra on s generators of degree
one. Passage to -indecomposables gives the natural transformation , which identifies with the dual of the
composition of the Singer transfer and the Lannes-Zarati homomorphism.
The main result of the paper proves the weak generalized algebraic spherical
class conjecture, which was proposed by the first named author. Namely, this
morphism is trivial on elements of positive degree when s>2. The condition s>2
is necessary, as exhibited by the spherical classes of Hopf invariant one and
those of Kervaire invariant one.Comment: v2 15 pages. Minor revision. v3 17 pages, revision following
referee's recommendations. Accepted for publication J. Al
Question of Peccei-Quinn symmetry and quark masses in the economical 3-3-1 model
We show that there is an infinite number of U(1) symmetries like Peccei-Quinn
symmetry in the 3-3-1 model with minimal scalar sector---two scalar triplets.
Moreover, all of them are completely broken due to the model's scalars by
themselves (notice that these scalars as known have been often used to break
the gauge symmetry and generating the masses for the model's particles). There
is no any residual Peccei-Quinn symmetry. Because of the minimal scalar content
there are some quarks that are massless at tree-level, but they can get
consistent mass contributions at one-loop due to this fact. Interestingly,
axions as associated with the mentioned U(1)s breaking (including Majoron due
to lepton-charge breaking) are all gauged away because they are also the
Goldstone bosons responsible for the gauge symmetry breaking as usual.Comment: 25 pages, 4 figures, revised version, to appear in Physical Review
Quantum many-body models with cold atoms coupled to photonic crystals
Using cold atoms to simulate strongly interacting quantum systems represents
an exciting frontier of physics. However, as atoms are nominally neutral point
particles, this limits the types of interactions that can be produced. We
propose to use the powerful new platform of cold atoms trapped near
nanophotonic systems to extend these limits, enabling a novel quantum material
in which atomic spin degrees of freedom, motion, and photons strongly couple
over long distances. In this system, an atom trapped near a photonic crystal
seeds a localized, tunable cavity mode around the atomic position. We find that
this effective cavity facilitates interactions with other atoms within the
cavity length, in a way that can be made robust against realistic
imperfections. Finally, we show that such phenomena should be accessible using
one-dimensional photonic crystal waveguides in which coupling to atoms has
already been experimentally demonstrated
Large signal of within the constraints of decays in the 3-3-1 model with neutral leptons
In the framework of the 3-3-1 model with neutral leptons, we have
investigated the lepton-flavor-violating sources based on the Higgs mass
spectrum which has two neutral Higgses identitied with corresponding ones in
the Two-Higgs-Doublet model (THDM). On the scale of the LHC,
we point out the parameter space regions where the experimental limits of decays are satisfied. These regions depend heavily on
the mixing of exotic leptons but are predicted to have large signals. We also show that
can reach a value of .Comment: 30 pages, 9 figure
Poincar\'e gauge theory with even and odd parity dynamic connection modes: isotropic Bianchi cosmological models
The Poincar\'e gauge theory of gravity has a metric compatible connection
with independent dynamics that is reflected in the torsion and curvature. The
theory allows two good propagating spin-0 modes. Dynamical investigations using
a simple expanding cosmological model found that the oscillation of the 0
mode could account for an accelerating expansion similar to that presently
observed. The model has been extended to include a mode and more
recently cross parity couplings. We investigate the dynamics of this model in a
situation which is simple, non-trivial, and yet may give physically interesting
results that might be observable. We consider homogeneous cosmologies, more
specifically, isotropic Bianchi class A models. We find an effective Lagrangian
for our dynamical system, a system of first order equations, and present some
typical dynamical evolution.Comment: 8 pages, 1 figures, submitted to IARD 2010 Conference Proceedings in
{\em Journal of Physics: Conference Series}, eds. L. Horwitz and M. Land
(2011
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