1,276 research outputs found
The Antighost Equation in N=1 Super-Yang-Mills Theories
The antighost equation valid for usual gauge theories in the Landau gauge, is
generalized to the case of supersymmetric gauge theories in a
supersymmetric version of the Landau gauge. This equation, which expresses the
nonrenormalization of the Faddeev-Popov ghost field, plays an important role in
the proof of the nonrenormalization theorems for the chiral anomalies.Comment: 8 pages, for the sake of clarity expressions (3.1) and (3.2) have
been modified. Due to an E-mail error, the old file was empt
Quantization of the Jackiw-Teitelboim model
We study the phase space structure of the Jackiw-Teitelboim model in its
connection variables formulation where the gauge group of the field theory is
given by local SL(2,R) (or SU(2) for the Euclidean model), i.e. the de Sitter
group in two dimensions. In order to make the connection with two dimensional
gravity explicit, a partial gauge fixing of the de Sitter symmetry can be
introduced that reduces it to spacetime diffeomorphisms. This can be done in
different ways. Having no local physical degrees of freedom, the reduced phase
space of the model is finite dimensional. The simplicity of this gauge field
theory allows for studying different avenues for quantization, which may use
various (partial) gauge fixings. We show that reduction and quantization are
noncommuting operations: the representation of basic variables as operators in
a Hilbert space depend on the order chosen for the latter. Moreover, a
representation that is natural in one case may not even be available in the
other leading to inequivalent quantum theories.Comment: Published version, a short note (not present in the published
version) on the quantization of the null sector has been adde
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
On the finiteness of the BRS modulo-d cocycles
Ladders of field polynomial differential forms obeying systems of descent
equations and corresponding to observables and anomalies of gauge theories are
renormalized. They obey renormalized descent equations. Moreover they are shown
to have vanishing anomalous dimensions. As an application a simple proof of the
nonrenormalization theorem for the nonabelian gauge anomaly is given.Comment: 21 p., UGVA-DPT 1992/03-759, Publ. in Nucl Phys. B381 (1992) 37
Algebraic Properties of BRST Coupled Doublets
We characterize the dependence on doublets of the cohomology of an arbitrary
nilpotent differential s (including BRST differentials and classical linearized
Slavnov-Taylor (ST) operators) in terms of the cohomology of the
doublets-independent component of s. All cohomologies are computed in the space
of local integrated formal power series. We drop the usual assumption that the
counting operator for the doublets commutes with s (decoupled doublets) and
discuss the general case where the counting operator does not commute with s
(coupled doublets). The results are purely algebraic and do not rely on
power-counting arguments.Comment: Some explanations enlarged, references adde
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
Collaborative effects in polymer translocation and the appearance of fictitious free-energy barriers
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