4,521 research outputs found
Normal Bundles, Pfaffians and Anomalies
We deal with the problem of diffeomorphism anomaly in theories with branes.
In particular we thoroughly analyze the problem of the residual chiral anomaly
of a five-brane immersed in M-theory, paying attention to its global
formulation in the five-brane world-volume. We conclude that the anomaly can be
canceled by a {\it local} counterterm in the five-brane world-volume.Comment: 17 pages, Latex, sign convention changed, typos correcte
Abelian 3-form gauge theory: superfield approach
We discuss a D-dimensional Abelian 3-form gauge theory within the framework
of Bonora-Tonin's superfield formalism and derive the off-shell nilpotent and
absolutely anticommuting Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST
symmetry transformations for this theory. To pay our homage to Victor I.
Ogievetsky (1928-1996), who was one of the inventors of Abelian 2-form
(antisymmetric tensor) gauge field, we go a step further and discuss the above
D-dimensional Abelian 3-form gauge theory within the framework of BRST
formalism and establish that the existence of the (anti-)BRST invariant
Curci-Ferrari (CF) type of restrictions is the hallmark of any arbitrary p-form
gauge theory (discussed within the framework of BRST formalism).Comment: LaTeX file, 8 pages, Talk delivered at BLTP, JINR, Dubna, Moscow
Region, Russi
Generalized q-deformed Correlation Functions as Spectral Functions of Hyperbolic Geometry
We analyse the role of vertex operator algebra and 2d amplitudes from the
point of view of the representation theory of infinite dimensional Lie
algebras, MacMahon and Ruelle functions. A p-dimensional MacMahon function is
the generating function of p-dimensional partitions of integers. These
functions can be represented as amplitudes of a two-dimensional c=1 CFT. In
this paper we show that p-dimensional MacMahon functions can be rewritten in
terms of Ruelle spectral functions, whose spectrum is encoded in the
Patterson-Selberg function of three dimensional hyperbolic geometry.Comment: 12 pages, no figure
Supersymmetrization of horizontality condition: nilpotent symmetries for a free spinning relativistic particle
We derive the off-shell nilpotent and absolutely anticommuting
Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for a
supersymmetric system of a free spinning relativistic particle within the
framework of superfield approach to BRST formalism. A novel feature of our
present investigation is the consistent and clear supersymmetric modification
of the celebrated horizontality condition for the precise determination of the
proper (anti-)BRST symmetry transformations for all the bosonic and fermionic
dynamical variables of our theory which is considered on a (1, 2)-dimensional
supermanifold parameterized by an even (bosonic) variable (\tau) and a pair of
odd (fermionic) variables \theta and \bar\theta (with \theta^2 = \bar\theta^2 =
0,\; \theta \bar\theta + \bar\theta \theta = 0) of the Grassmann algebra. One
of the most important features of our present investigation is the derivation
of (anti-)BRST invariant Curci-Ferrari type restriction which turns out to be
responsible for the absolute anticommutativity of the (anti-)BRST symmetry
transformations and existence of the coupled (but equivalent) Lagrangians for
the present theory of a supersymmetric system.Comment: LaTeX file, 24 pages, version to appear in EPJ
Axial gravity: a non-perturbative approach to split anomalies
In a theory of a Dirac fermion field coupled to a metric-axial-tensor (MAT)
background, using a Schwinger-DeWitt heat kernel technique, we compute
non-perturbatively the two (odd parity) trace anomalies. A suitable collapsing
limit of this model corresponds to a theory of chiral fermions coupled to
(ordinary) gravity. Taking this limit on the two computed trace anomalies we
verify that they tend to the same expression, which coincides with the already
found odd parity trace anomaly, with the identical coefficient. This confirms
our previous results on this issue.Comment: 43 pages, some additions in section 6.3 and 6.5 plus minor
correction
Wilson Renormalization Group for Supersymmetric Gauge Theories and Gauge Anomalies
We extend the Wilson renormalization group (RG) to supersymmetric theories.
As this regularization scheme preserves supersymmetry, we exploit the
superspace technique. To set up the formalism we first derive the RG flow for
the massless Wess-Zumino model and deduce its perturbative expansion. We then
consider N=1 supersymmetric Yang-Mills and show that the local gauge symmetry
-broken by the regularization- can be recovered by a suitable choice of the RG
flow boundary conditions. We restrict our analysis to the first loop, the
generalization to higher loops presenting no difficulty due to the iterative
nature of the procedure. Furthermore, adding matter fields, we reproduce the
one-loop supersymmetric chiral anomaly to the second order in the vector field.Comment: 22 pages, 1 Postscript figure, uses amssym
Recovering pyramid WS gain in non-common path aberration correction mode via deformable lens
It is by now well known that pyramid based wavefront sensors, once in closed
loop, have the capability to improve more and more the gain as the reference
natural star image size is getting smaller on the pyramid pin. Especially in
extreme adaptive optics applications, in order to correct the non-common path
aberrations between the scientific and sensing channel, it is common use to
inject a certain amount of offset wavefront deformation into the DM(s),
departing at the same time the pyramid from the optimal working condition. In
this paper we elaborate on the possibility to correct the low order non-common
path aberrations at the pyramid wavefront sensor level by means of an adaptive
refractive lens placed on the optical path before the pyramid itself, allowing
the mitigation of the gain loss
Analyticity Properties of Graham-Witten Anomalies
Analytic properties of Graham-Witten anomalies are considered. Weyl anomalies
according to their analytic properties are of type A (coming from
-singularities in correlators of several energy-momentum tensors) or of
type B (originating in counterterms which depend logarithmically on a mass
scale). It is argued that all Graham-Witten anomalies can be divided into 2
groups: internal and external, and that all external anomalies are of type B,
whereas among internal anomalies there is one term of type A and all the rest
are of type B. This argument is checked explicitly for the case of a free
scalar field in a 6-dimensional space with a 2-dimensional submanifold.Comment: 2 typos correcte
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