586 research outputs found
N=2 Super Yang Mills Action and BRST Cohomology
The extended BRST cohomology of N=2 super Yang-Mills theory is discussed in
the framework of Algebraic Renormalization. In particular, N=2 supersymmetric
descent equations are derived from the cohomological analysis of linearized
Slavnov-Taylor operator \B. It is then shown that both off- and on-shell N=2
super Yang-Mills actions are related to a lower-dimensional gauge invariant
field polynomial Tr\f^2 by solving these descent equations. Moreover, it is
found that these off- and on-shell solutions differ only by a \B-exact term,
which can be interprated as a consequence of the fact that the cohomology of
both cases are the same.Comment: Latex, 1+13 page
Realization of within the differntial algebra on
We realize the Hopf algebra as an algebra of differential
operators on the quantum Euclidean space . The generators are
suitable q-deformed analogs of the angular momentum components on ordinary
. The algebra of functions on
splits into a direct sum of irreducible vector representations of
; the latter are explicitly constructed as highest weight
representations.Comment: 26 pages, 1 figur
Unitarity bounds and RG flows in time dependent quantum field theory
We generalize unitarity bounds on operator dimensions in conformal field
theory to field theories with spacetime dependent couplings. Below the energy
scale of spacetime variation of the couplings, their evolution can strongly
affect the physics, effectively shifting the infrared operator scaling and
unitarity bounds determined from correlation functions in the theory. We
analyze this explicitly for large- double-trace flows, and connect these to
UV complete field theories. One motivating class of examples comes from our
previous work on FRW holography, where this effect explains the range of
flavors allowed in the dual, time dependent, field theory.Comment: 38 page
Twisted Covariant Noncommutative Self-dual Gravity
A twisted covariant formulation of noncommutative self-dual gravity is
presented. The formulation for constructing twisted noncommutative Yang-Mills
theories is used. It is shown that the noncommutative torsion is solved at any
order of the -expansion in terms of the tetrad and some extra fields of
the theory. In the process the first order expansion in for the
Pleba\'nski action is explicitly obtained.Comment: 23+1 pages, no figures, corrected typos, references and Appendix B is
adde
Cancellation of the Chiral Anomaly in a Model with Spontaneous Symmetry Breaking
A perturbatively renormalized Abelian Higgs-Kibble model with a chirally
coupled fermion is considered. The Slavnov identity is fulfilled to all orders
of perturbation theory, which is crucial for renormalizability in models with
vector bosons. BRS invariance, i.e. the validity of the identity, forces the
chiral anomaly to be cancelled by Wess-Zumino counterterms. This procedure
preserves the renormalizability in the one-loop approximation but it violates
the Froissart bounds for partial wave amplitudes above some energy and destroys
renormalizability from the second order in h bar onwards due to the
counterterms. (The paper has 3 figs. in postscript which are not included; send
request to the author's e-mailbox with subject: figures . The author is willing
to mail hard copies of the paper.)Comment: 13 pages, plain TeX, SI 92-1
Superfield Realizations of Lorentz and CPT Violation
Superfield realizations of Lorentz-violating extensions of the Wess-Zumino
model are presented. These models retain supersymmetry but include terms that
explicitly break the Lorentz symmetry. The models can be understood as arising
from superspace transformations that are modifications of the familiar one in
the Lorentz-symmetric case.Comment: 10 page
The Three Dimensional Dual of 4D Chirality
Chiral gauge theories can be defined in four-dimensional Anti de Sitter
space, but AdS boundary conditions explicitly break the chiral symmetry in a
specific, well defined manner, which in turns results in an anomalous Ward
identity. When the 4D theory admits a dual description in terms of a 3D CFT,
the 3D dual of the broken chiral symmetry is a certain double-trace deformation
of the CFT, which produces the same anomalous chiral Ward identities that
obtains in the 4D bulk theory.Comment: 10 pages, small misprints corrected, reference [16] updated. Version
to appear in JHE
Unbraiding the braided tensor product
We show that the braided tensor product algebra
of two module algebras of a quasitriangular Hopf algebra is
equal to the ordinary tensor product algebra of with a subalgebra of
isomorphic to , provided there exists a
realization of within . In other words, under this assumption we
construct a transformation of generators which `decouples' (i.e.
makes them commuting). We apply the theorem to the braided tensor product
algebras of two or more quantum group covariant quantum spaces, deformed
Heisenberg algebras and q-deformed fuzzy spheres.Comment: LaTex file, 29 page
Duality invariance of non-anticommutative N=1/2 supersymmetric U(1) gauge theory
A parent action is introduced to formulate (S-) dual of non-anticommutative
N=1\2 supersymmetric U(1) gauge theory. Partition function for parent action in
phase space is utilized to establish the equivalence of partition functions of
the theories which this parent action produces. Thus, duality invariance of
non-anticommutative N=1\2 supersymmetric U(1) gauge theory follows. The results
which we obtained are valid at tree level or equivalently at the first order in
the nonanticommutativity parameter C_{\mu\nu}.Comment: 12 pages, some comments and references are added. To appear in JHE
Constructive algebraic renormalization of the abelian Higgs-Kibble model
We propose an algorithm, based on Algebraic Renormalization, that allows the
restoration of Slavnov-Taylor invariance at every order of perturbation
expansion for an anomaly-free BRS invariant gauge theory. The counterterms are
explicitly constructed in terms of a set of one-particle-irreducible Feynman
amplitudes evaluated at zero momentum (and derivatives of them). The approach
is here discussed in the case of the abelian Higgs-Kibble model, where the zero
momentum limit can be safely performed. The normalization conditions are
imposed by means of the Slavnov-Taylor invariants and are chosen in order to
simplify the calculation of the counterterms. In particular within this model
all counterterms involving BRS external sources (anti-fields) can be put to
zero with the exception of the fermion sector.Comment: Jul, 1998, 31 page
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