1,146 research outputs found
The Renormalization Group for Flag Manifolds
The renormalization group equations for a class of non--relativistic quantum
--models targeted on flag manifolds are given. These models emerge in a
continuum limit of generalized Heisenberg antiferromagnets. The case of the
manifold is studied in greater detail. We show
that at zero temperature there is a fixed point of the RG transformations in
--dimensions where the theory becomes relativistic. We study
the linearized RG transformations in the vicinity of this fixed point and show
that half of the couplings are irrelevant. We also show that at this fixed
point there is an enlargement of the global isometries of the target manifold.
We construct a discrete non--abelian enlargement of this kind.Comment: 22 page
Continuous Local Symmetry in Ising-type Models
A class of generalized Ising models is examined with a view to extracting a
low energy sector comprising
Dirac fermions coupled to Yang-Mills vectors. The main feature of this
approach is a set of gap equations, covariant with respect to one of the
-dimensional crystallographic space groups.Comment: 7 pages, latex, IC/94/2
Loss of strumpellin in the melanocytic lineage impairs the WASH Complex but does not affect coat colour
The five-subunit WASH complex generates actin networks that participate in endocytic trafficking, migration and invasion in various cell types. Loss of one of the two subunits WASH or strumpellin in mice is lethal, but little is known about their role in mammals in vivo. We explored the role of strumpellin, which has previously been linked to hereditary spastic paraplegia, in the mouse melanocytic lineage. Strumpellin knockout in melanocytes revealed abnormal endocytic vesicle morphology but no impairment of migration in vitro or in vivo and no change in coat colour. Unexpectedly, WASH and filamentous actin could still localize to vesicles in the absence of strumpellin, although the shape and size of vesicles was altered. Blue native PAGE revealed the presence of two distinct WASH complexes, even in strumpellin knockout cells, revealing that the WASH complex can assemble and localize to endocytic compartments in cells in the absence of strumpellin
Dissociative Autoionization in (1+2)-photon Above Threshold Excitation of H2 Molecules
We have theoretically studied the effect of dissociative autoionization on
the photoelectron energy spectrum in (1+2)-photon above threshold
ionization(ATI) of H2 molecules. We have considered excitation from the ground
state X-singlet-Sigma-g+(v=0,j) to the doubly excited autoionizing states of
singlet-Sigma-u+ and singlet-Pi-u+ symmetry, via the intermediate resonant
B-singlet-Sigma-u+(v=5,j) states. We have shown that the photoelectron energy
spectrum is oscillatory in nature and shows three distinct peaks above the
photoelectron energy 0.7 eV. This feature has been observed in a recent
experiment by Rottke et al, J. Phys. B, Vol. 30, p-4049 (1997).Comment: 11 pages and 4 figure
Topology, Quantum Gravity and Particle Physics
It is argued that quantum gravity has an interpretation as a topological
field theory provided a certain constraint from the path intergral measure is
respected. The constraint forces us to couple gauge and matter fields to
gravity for space - time dimensions different from 3. We then discuss possible
models which may be relevant to our universe.Comment: 18 pages, LaTeX. Replaced version corrects typos and has additional
reference
Consistent and covriant anomalies in the overlap formulation of chiral gauge theories
In this letter we show how the covariant anomaly emerges in the overlap
scheme. We also prove that the overlap scheme correctly reproduces the anomaly
in the flavour currents such as in vector like theories like QCD.Comment: 10 pages, Late
BLACK HOLE MULTIPLETS AND SPONTANEOUS BREAKING OF LOCAL SUPERSYMMETRY
We classify states saturating a double or a single supersymmetric positivity
bound of a four-dimensional N=4 supersymmetry. The massive four-dimensional
double-bound states (Bogomolny states) are shown to form a light-like
representation of ten-dimensional supersymmetry. The single-bound states form a
massive representation (centrino multiplet) of a four-dimensional
supersymmetry. The first component of the centrino multiplet is identified with
extreme black holes with regular horizon which have one quarter of unbroken
supersymmetry. The centrino multiplet includes a massive spin 3/2 state, the
centrino, as a highest spin state.
Existence of massive black hole supermultiplets may affect the massless
sector of the theory. Assuming that gluino condensate is formed one can study
its properties. The bilinear combination of covariantly constant Killing
spinors supplies the possible form for a gluino condensate. The condensate has
null properties, does not introduce a cosmological constant, and may lead to a
spontaneous breaking of local supersymmetry. This suggests that centrino may
provide a consistent super-Higgs mechanism.Comment: 15 pages, LaTe
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