579 research outputs found
Bosonization in d > 2 dimensions
I discuss in this talk a bosonization approach recently developed. It leads
to the (exact) bosonization rule for fermion currents in d > 2 dimensions and
also provides a systematic way of constructing the bosonic action in different
regimes.Comment: Talk given at "Trends in Theoretical Physics, CERN - Santiago de
Compostela - La Plata Meeting", La Plata, April 1997, 34 pages, late
Lifshitz holography with a probe Yang-Mills field
Taking as a probe an SU(2) gauge field with Yang-Mills action in a 3+1
dimensional Lifshitz black hole background, we use the gauge/gravity
correspondence to discuss finite temperature effects in the dual theory defined
on the boundary. In order to test the dependence of results on the anisotropic
scaling exponent z we consider two analytical black hole solutions with z=2 and
z=4. Apart from solving the equations of motion in the bulk using a numerical
approach, we also apply an analytical approximation allowing the determination
of the phase transition character, the critical exponent and the critical
temperature behavior as a function of z.Comment: 12 pages, 3 figure
Nonabelianization of Higgs bundles
The character varieties of representations of a surface group into the Lie
groups SL(m,H), SO(2m,H) and Sp(m,m) have a holomorphic description in terms of
the moduli space of Higgs bundles. We show that the fibres of the integrable
system in these cases are not abelian varieties, but are instead moduli spaces
of rank 2 bundles on a spectral curve, satisfying natural stability conditions
The dyon charge in noncommutative gauge theories
We present an explicit classical dyon solution for the noncommutative version
of the Yang-Mills-Higgs model (in the Prasad-Sommerfield limit) with a tehta
term. We show that the relation between classical electric and magnetic charges
also holds in noncommutative space. Extending the Noether approach to the case
of a noncommutative gauge theory, we analyze the effect of CP violation at the
quantum level, induced both by the theta term and by noncommutativity and we
prove that the Witten effect formula for the dyon charge remains the same as in
ordinary space.Comment: 17 page
A trust model for spreading gossip in social networks
We introduce here a multi-type bootstrap percolation model, which we call
T-Bootstrap Percolation (T-BP), and apply it to study information propagation
in social networks. In this model, a social network is represented by a graph G
whose vertices have different labels corresponding to the type of role the
person plays in the network (e.g. a student, an educator, etc.). Once an
initial set of vertices of G is randomly selected to be carrying a gossip (e.g.
to be infected), the gossip propagates to a new vertex provided it is
transmitted by a minimum threshold of vertices with different labels. By
considering random graphs, which have been shown to closely represent social
networks, we study different properties of the T-BP model through numerical
simulations, and describe its implications when applied to rumour spread, fake
news, and marketing strategies.Comment: 9 pages, 9 figure
Vortex solutions of an Abelian Higgs model with visible and hidden sectors
We study vortex solutions in a theory with dynamics governed by two weakly
coupled Abelian Higgs models, describing a hidden sector and a visible sector.
We analyze the radial dependence of the axially symmetric solutions constructed
numerically and discuss the stability of vortex configurations for different
values of the model parameters, studying in detail vortex decay into lower
energy configurations. We find that even in a weak coupling regime vortex
solutions strongly depend on the parameters of both the visible and hidden
sectors. We also discuss on qualitative grounds possible implications of the
existence of a hidden sector in connection with superconductivity.Comment: 22 pages, 10 figures, version accepted in JHE
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