5 research outputs found
Construction of BRST invariant states in WZNW models.
We study the cohomology arising in the BRST formulation of G/H gauged WZNW
models, i.e. in which the states of the gauged theory are projected out from
the ungauged one by means of a BRST condition. We will derive for a general
simple group with arbitrary level, conditions for which the cohomology is
non-trivial. We show, by introducing a small perturbation due to Jantzen, in
the highest weights of the representations, how states in the cohomology,
"singlet pairs", arise from unphysical states, "Kugo-Ojima quartets", as the
perturbation is set to zero. This will enable us to identify and construct
states in the cohomology. The ghost numbers that will occur are , with
uniquely determined by the representations of the algebras involved. Our
construction is given in terms of the current modes and relies on the explicit
form of highest weight null-states given by Malikov, Feigen and Fuchs.Comment: 12 pages, late
The Canonical Structure of Wess-Zumino-Witten Models
The phase space of the Wess-Zumino-Witten model on a circle with target space
a compact, connected, semisimple Lie group is defined and the corresponding
symplectic form is given. We present a careful derivation of the Poisson
brackets of the Wess-Zumino-Witten model. We also study the canonical structure
of the supersymmetric and the gauged Wess-Zumino-Witten models.Comment: 16pp (revised version - two new sections added and relation with
other recent work discussed
Exact Bosonic and Supersymmetric String Black Hole Solutions
We show that Witten's two-dimensional string black hole metric is exactly
conformally invariant in the supersymmetric case. We also demonstrate that this
metric, together with a recently proposed exact metric for the bosonic case,
are respectively consistent with the supersymmetric and bosonic -model
conformal invariance conditions up to four-loop order.Comment: 14
The BRST formulation of G/H WZNW models
We consider a BRST approach to G/H coset WZNW models, {\it i.e.} a
formulation in which the coset is defined by a BRST condition. We will give the
precise ingrediences needed for this formulation. Then we will prove the
equivalence of this approach to the conventional coset formulation by solving
the the BRST cohomology. This will reveal a remarkable connection between
integrable representations and a class of non-integrable representations for
negative levels. The latter representations are also connected to string
theories based on non-compact WZNW models. The partition functions of G/H
cosets are also considered. The BRST approach enables a covariant construction
of these, which does not rely on the decomposition of G as . We
show that for the well-studied examples of
and , we exactly reproduce the previously known results.Comment: 23 pages latex file. G\"oteborg ITP 93-01 ( Not encoded version