69 research outputs found
Non-Abelian Vortices without Dynamical Abelianization
Vortices carrying truly non-Abelian flux moduli, which do not dynamically
reduce to Abelian vortices, are found in the context of softly-broken supersymmetric chromodynamics (SQCD). By tuning the bare quark masses
appropriately we identify the vacuum in which the underlying SU(N) gauge group
is partially broken to SU(n) \times SU(r) \times U(1)/{\mathbbm Z}_{K}, where
is the least common multiple of , and with and
flavors of light quark multiplets. At much lower energies the
gauge group is broken completely by the squark VEVs, and vortices develop which
carry non-Abelian flux moduli . For we argue
that the SU(n) fluctuations become strongly coupled and Abelianize, while
leaving weakly fluctuating flux moduli. This allows us to recognize the
semi-classical origin of the light non-Abelian monopoles found earlier in the
fully quantum-mechanical treatment of 4D SQCD.Comment: 22 pages, 4 figures, One section (Section 2) added, and an extended
discussion added in Section
On the thermodynamic path enabling a room-temperature, laser-assisted graphite to nanodiamond transformation
Nanodiamonds are the subject of active research for their potential applications in nano-magnetometry, quantum optics, bioimaging and water cleaning processes. Here, we present a novel thermodynamic model that describes a graphite-liquid-diamond route for the synthesis of nanodiamonds. Its robustness is proved via the production of nanodiamonds powders at room-temperature and standard atmospheric pressure by pulsed laser ablation of pyrolytic graphite in water. The aqueous environment provides a confinement mechanism that promotes diamond nucleation and growth, and a biologically compatible medium for suspension of nanodiamonds. Moreover, we introduce a facile physico-chemical method that does not require harsh chemical or temperature conditions to remove the graphitic byproducts of the laser ablation process. A full characterization of the nanodiamonds by electron and Raman spectroscopies is reported. Our model is also corroborated by comparison with experimental data from the literature
Malaria in illegal Chinese immigrants, Italy.
A cluster of 22 imported malaria cases, 21 caused by Plasmodium falciparum, was observed among illegal Chinese immigrants in northern Italy in the summer of 2000. The rate of severe disease was high because the patients were not immune and they sought health-care services late in their illness because of their clandestine status. Recognition of the outbreak was delayed because no regional alert system among infectious diseases hospitals was in place
Large N and Bosonization in Three Dimensions
Bosonization is normally thought of as a purely two-dimensional phenomenon,
and generic field theories with fermions in D>2 are not expected be describable
by local bosonic actions, except in some special cases. We point out that 3D
SU(N) gauge theories on R^{1,1} x S^{1}_{L} with adjoint fermions can be
bosonized in the large N limit. The key feature of such theories is that they
enjoy large N volume independence for arbitrary circle size L. A consequence of
this is a large N equivalence between these 3D gauge theories and certain 2D
gauge theories, which matches a set of correlation functions in the 3D theories
to corresponding observables in the 2D theories. As an example, we focus on a
3D SU(N) gauge theory with one flavor of adjoint Majorana fermions and derive
the large-N equivalent 2D gauge theory. The extra dimension is encoded in the
color degrees of freedom of the 2D theory. We then apply the technique of
non-Abelian bosonization to the 2D theory to obtain an equivalent local theory
written purely in terms of bosonic variables. Hence the bosonized version of
the large N three-dimensional theory turns out to live in two dimensions.Comment: 30 pages, 2 tables. v2 minor revisions, references adde
Group Theory of Non-Abelian Vortices
We investigate the structure of the moduli space of multiple BPS non-Abelian
vortices in U(N) gauge theory with N fundamental Higgs fields, focusing our
attention on the action of the exact global (color-flavor diagonal) SU(N)
symmetry on it. The moduli space of a single non-Abelian vortex, CP(N-1), is
spanned by a vector in the fundamental representation of the global SU(N)
symmetry. The moduli space of winding-number k vortices is instead spanned by
vectors in the direct-product representation: they decompose into the sum of
irreducible representations each of which is associated with a Young tableau
made of k boxes, in a way somewhat similar to the standard group composition
rule of SU(N) multiplets. The K\"ahler potential is exactly determined in each
moduli subspace, corresponding to an irreducible SU(N) orbit of the
highest-weight configuration.Comment: LaTeX 46 pages, 4 figure
The SAGEX Review on Scattering Amplitudes
This is an introduction to, and invitation to read, a series of review
articles on scattering amplitudes in gauge theory, gravity, and superstring
theory. Our aim is to provide an overview of the field, from basic aspects to a
selection of current (2022) research and developments.Comment: 15 pages, overview articl
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