535 research outputs found
Symmetries of noncommutative scalar field theory
We investigate symmetries of the scalar field theory with harmonic term on
the Moyal space with euclidean scalar product and general symplectic form. The
classical action is invariant under the orthogonal group if this group acts
also on the symplectic structure. We find that the invariance under the
orthogonal group can be restored also at the quantum level by restricting the
symplectic structures to a particular orbit.Comment: 12 pages, revised versio
Connes distance by examples: Homothetic spectral metric spaces
We study metric properties stemming from the Connes spectral distance on
three types of non compact noncommutative spaces which have received attention
recently from various viewpoints in the physics literature. These are the
noncommutative Moyal plane, a family of harmonic Moyal spectral triples for
which the Dirac operator squares to the harmonic oscillator Hamiltonian and a
family of spectral triples with Dirac operator related to the Landau operator.
We show that these triples are homothetic spectral metric spaces, having an
infinite number of distinct pathwise connected components. The homothetic
factors linking the distances are related to determinants of effective Clifford
metrics. We obtain as a by product new examples of explicit spectral distance
formulas. The results are discussed.Comment: 23 pages. Misprints corrected, references updated, one remark added
at the end of the section 3. To appear in Review in Mathematical Physic
Anyonic Excitations in Fast Rotating Bose Gases Revisited
The role of anyonic excitations in fast rotating harmonically trapped Bose
gases in a fractional Quantum Hall state is examined. Standard Chern-Simons
anyons as well as "non standard" anyons obtained from a statistical interaction
having Maxwell-Chern-Simons dynamics and suitable non minimal coupling to
matter are considered. Their respective ability to stabilize attractive Bose
gases under fast rotation in the thermodynamical limit is studied. Stability
can be obtained for standard anyons while for non standard anyons, stability
requires that the range of the corresponding statistical interaction does not
exceed the typical wavelenght of the atoms.Comment: 5 pages. Improved version to be published in Phys. Rev. A, including
a physical discussion on relevant interactions and scattering regime together
with implication on the nature of statistical interactio
On Auxiliary Fields in BF Theories
We discuss the structure of auxiliary fields for non-Abelian BF theories in
arbitrary dimensions. By modifying the classical BRST operator, we build the
on-shell invariant complete quantum action. Therefore, we introduce the
auxiliary fields which close the BRST algebra and lead to the invariant
extension of the classical action.Comment: 7 pages, minor changes, typos in equations corrected and
acknowledgements adde
MerTK mediates immune homeostasis: effects upon dendritic cell function and Type 1 diabetes
The receptor tyrosine kinase Mer (MerTK) is expressed by dendritic cells (DC) in mice. The heretofore undefined role of MerTK in DC was investigated in two major studies. First, the role of MerTK in the inhibition of DC activation by apoptotic cells was investigated. It was found that apoptotic cells inhibited DC activation by bacterial lipopolysaccharide or CD40 crosslinking via MerTK. Inhibition of DC was characterized by blockade of IL-12p70 secretion, co-stimulatory molecule expression and stimulation of CD4+ and CD8+ T cells. The MerTK ligand growth arrest specific factor-6 (Gas6) was expressed on the surface of apoptotic cells, and Gas6 was essential for the inhibitory effects of apoptotic cells upon DC. Non-obese diabetic (NOD) mice, lacking MerTK expression (NOD.MerTKKD/KD), demonstrated aberrant expansion of type 1 CD4+ and CD8+ T cell effectors in response to apoptotic cell death in vivo. Furthermore, NOD.MerTKKD/KD mice expressing a diabetogenic T cell receptor transgene, developed diabetes at an accelerated rate and a greater frequency than mice expressing MerTK. These findings support a role for MerTK in peripheral immune homeostasis. Secondly, the impact of MerTK-deficiency in NOD mice was investigated. NOD.MerTKKD/KD mice were protected from diabetes onset and protection was due to lack of self-specific type 1 CD4+ and CD8+ T cell effectors. Thymic selection was enhanced in NOD.MerTKKD/KD mice resulting in deletion of pathogenic, autoreactive T cells. The change in thymic selection efficiency was mediated by bone marrow-derived cells and was likely due to dysregulation of thymic DC. These data indicate that MerTK mediates immunoregulation of DC in both the periphery and the thymus
Using mixed data in the inverse scattering problem
Consider the fixed- inverse scattering problem. We show that the zeros
of the regular solution of the Schr\"odinger equation, , which are
monotonic functions of the energy, determine a unique potential when the domain
of the energy is such that the range from zero to infinity. This
suggests that the use of the mixed data of phase-shifts
, for which the zeros of the regular solution are monotonic in both domains,
and range from zero to infinity, offers the possibility of determining the
potential in a unique way.Comment: 9 pages, 2 figures. Talk given at the Conference of Inverse Quantum
Scattering Theory, Hungary, August 200
Chimeric protein and nano-construct for tissue-retained enzyme to locally suppress inflammation
There is considerable need for new retention strategies of immunomodulatory biologics for localized suppression of inflammation. We developed a chimeric protein as a well as a self-assembled nano-construct incorporating novel approaches for both retention and suppression to induce potent, confined metabolic programming. Immunosuppressive indoleamine 2,3 dioxygenase (IDO), which depletes tryptophan through the kynurenine pathway, was fused to Galectin 3 (Gal3), which binds extracellular glycans and provides tissue anchoring. Using a luciferase-Gal3 fusion reporter, tissue retention was prolonged to ~6 d whereas native luciferase is not retained and undetectable by 24 h. IDO-Gal3 injected subcutaneously controlled local LPS-challenged tissue inflammation. Furthermore, subgingival injection suppressed periodontal disease (PD) in a polymicrobial challenged mouse model. Multiplex analysis of gingival tissue revealed decreased inflammatory (IL-1β, IL-12p70, KC, IP10, MCP1, MIP2) and increased anti-inflammatory (IL-10, TGFβ3) proteins, indicating a shift toward homeostasis. Animals treated with IDO-Gal3 also showed significant decrease in bone loss commonly associated with PD, as determined by µCT analysis
Vortex in Maxwell-Chern-Simons models coupled to external backgrounds
We consider Maxwell-Chern-Simons models involving different non-minimal
coupling terms to a non relativistic massive scalar and further coupled to an
external uniform background charge. We study how these models can be
constrained to support static radially symmetric vortex configurations
saturating the lower bound for the energy. Models involving Zeeman-type
coupling support such vortices provided the potential has a "symmetry breaking"
form and a relation between parameters holds. In models where minimal coupling
is supplemented by magnetic and electric field dependant coupling terms, non
trivial vortex configurations minimizing the energy occur only when a non
linear potential is introduced. The corresponding vortices are studied
numericallyComment: LaTeX file, 2 figure
Examples of derivation-based differential calculi related to noncommutative gauge theories
Some derivation-based differential calculi which have been used to construct
models of noncommutative gauge theories are presented and commented. Some
comparisons between them are made.Comment: 22 pages, conference given at the "International Workshop in honour
of Michel Dubois-Violette, Differential Geometry, Noncommutative Geometry,
Homology and Fundamental Interactions". To appear in a special issue of
International Journal of Geometric Methods in Modern Physic
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