735 research outputs found
Sp(2)-Symmetric Lagrangian BRST Quantization
One Lagrangian BRST quantization principle is that of imposing correct
Schwinger-Dyson equations through the BRST Ward identities. In this paper we
show how to derive the analogous -symmetric quantization condition in
flat coordinates from an underlying -symmetric Schwinger-Dyson BRST
symmetry. We also show under what conditions this can be recast in the language
of triplectic quantization.Comment: LaTeX, 19 page
BRST Gauge Fixing and Regularization
In the presence of consistent regulators, the standard procedure of BRST
gauge fixing (or moving from one gauge to another) can require non-trivial
modifications. These modifications occur at the quantum level, and gauges exist
which are only well-defined when quantum mechanical modifications are correctly
taken into account. We illustrate how this phenomenon manifests itself in the
solvable case of two-dimensional bosonization in the path-integral formalism.
As a by-product, we show how to derive smooth bosonization in
Batalin-Vilkovisky Lagrangian BRST quantization.Comment: LaTeX, 12 page
Redefining B-twisted topological sigma models
A recently proposed variation on the usual procedure to perform the
topological B-twist in rigid models is applied to the case of the model on a K\"ahler manifold. This leads to an alternative description of
Witten's topological model, which allows for a proper BRST
interpretation and ghost number assignement. We also show that the auxiliary
fields, which are responsible for the off shell closure of the algebra,
play an important role in our construction.Comment: one reference adde
Recommended from our members
Integrating short-term demand response into long-term investment planning
Planning models have been used for many years to optimize generation investments in electric power systems. More recently, these models have been extended in order to treat demand-side management on an equal footing. This paper stresses the importance of integrating short-term demand response to time-varying prices into those investment models. Three different methodologies are suggested to integrate short-term responsiveness into a long-term model assuming that consumer response can be modelled using price-elastic demand and that generators behave competitively. First, numerical results show that considering operational constraints in an investment model results in less inflexible base load capacity and more mid-range capacity that has higher ramp rates. Then, own-price and cross-price elasticities are included in order to incorporate consumersâ willingness to adjust the demand profile in response to price changes. Whereas own-price elasticities account for immediate response to price signals, cross-price elasticities account for shifting loads to other periods. As energy efficiency programs sponsored by governments or utilities also influence the load profile, the interaction of energy efficiency expenditures and demand response is also modelled. In particular, reduced responsiveness to prices can be a side effect when consumers have become more energy efficient. Comparison of model results for a single year optimization with and without demand response shows the peak reduction and valley filling effects of response to real-time prices for an illustrative example with a large amount of wind power injections. Additionally, increasing demand elasticity increases the optimal amount of installed wind power capacity. This suggests that demand-side management can result in environmental benefits not only through reducing energy use, but also by facilitating integration of renewable energy
The regularized BRST Jacobian of pure Yang-Mills theory
The Jacobian for infinitesimal BRST transformations of path integrals for
pure Yang-Mills theory, viewed as a matrix \unity +\Delta J in the space of
Yang-Mills fields and (anti)ghosts, contains off-diagonal terms. Naively, the
trace of vanishes, being proportional to the trace of the structure
constants. However, the consistent regulator \cR, constructed from a general
method, also contains off-diagonal terms. An explicit computation demonstrates
that the regularized Jacobian Tr\ \Delta J\exp -\cR /M^2 for is the variation of a local counterterm, which we give. This is a
direct proof at the level of path integrals that there is no BRST anomaly.Comment: 12 pages, latex, CERN-TH.6541/92, KUL-TF-92/2
The BPHZ renormalised BV master equation and Two-loop Anomalies in Chiral Gravities
Anomalies and BRST invariance are governed, in the context of Lagrangian
Batalin-Vilkovisky quantization, by the master equation, whose classical limit
is . Using Zimmerman's normal products and the BPHZ renormalisation
method, we obtain a corresponding local quantum operator equation, which is
valid to all orders in perturbation theory. The formulation implies a
calculational method for anomalies to all orders that is useful also outside
the BV context and that remains completely within regularised perturbation
theory. It makes no difference in principle whether the anomaly appears at one
loop or at higher loops. The method is illustrated by computing the one- and
two-loop anomalies in chiral gravity.Comment: 44 pages, LaTex. 4 figures, epsf. Discussion in section 4 extended,
assorted small modifications, 3 references added. As it will be published in
NP
Relative efficacy of psychotherapy and pharmacotherapy in the treatment of depression; a meta-analysis,
Abstract We investigated the efficacy of pharmacotherapy and psychotherapy for depression by searching for RCT's. Studies were classified according to chronicity and severity and a meta-analysis was applied. Ten studies were included. Remission did not differ between psychotherapy (38%) and pharmacotherapy (35%). No differences were found in chronic, or in non-chronic depression, and in mild or in moderate depression. Both treatments performed better in mild than in moderate depression. Dropout was larger in pharmacotherapy (28%) than in psychotherapy (24%). At follow-up relapse in pharmacotherapy (57%) was higher than in psychotherapy (27%). Psychotherapy and pharmacotherapy appear equally efficacious in depression. Both treatments have larger effects in mild than in moderate depression, but similar effects in chronic and non-chronic depression and at follow-up psychotherapy outperforms pharmacotherapy
An alternative BRST operator for topological Landau-Ginzburg models
We propose a new BRST operator for the B-twist of N=2 Landau-Ginzburg (LG) models. It solves the problem of the fractional ghost numbers of Vafa's old BRST operator and shows how the model is obtained by gauge fixing a zero action. An essential role is played by the anti-BRST operator,which is given by one of the supersymmetries of the N=2 algebra. Its presence is needed in proving that the model is indeed a topological field theory. The space of physical observables, defined by taking the anti-BRST cohomology in the BRST cohomology groups, is unchanged
Superspace formulation of general massive gauge theories and geometric interpretation of mass-dependent BRST symmetries
A superspace formulation is proposed for the osp(1,2)-covariant Lagrangian
quantization of general massive gauge theories. The superalgebra os0(1,2) is
considered as subalgebra of sl(1,2); the latter may be considered as the
algebra of generators of the conformal group in a superspace with two
anticommuting coordinates. The mass-dependent (anti)BRST symmetries of proper
solutions of the quantum master equations in the osp(1,2)-covariant formalism
are realized in that superspace as invariance under translations combined with
mass-dependent special conformal transformations. The Sp(2) symmetry - in
particular the ghost number conservation - and the "new ghost number"
conservation are realized as invariance under symplectic rotations and
dilatations, respectively. The transformations of the gauge fields - and of the
full set of necessarily required (anti)ghost and auxiliary fields - under the
superalgebra sl(1,2) are determined both for irreducible and first-stage
reducible theories with closed gauge algebra.Comment: 35 pages, AMSTEX, precision of reference
- âŠ