4,685 research outputs found
SQCD Vacua and Geometrical Engineering
We consider the geometrical engineering constructions for the N = 1 SQCD
vacua recently proposed by Giveon and Kutasov. After one T-duality, the
geometries with wrapped D5 branes become N = 1 brane configurations with NS
branes and D4 branes. The field theories encoded by the geometries contain
extra massive adjoint fields for the flavor group. After performing a flop, the
geometries contain branes, antibranes and branes wrapped on non-holomorphic
cycles. The various tachyon condensations between pairs of wrapped D5 branes
and anti D5 branes together with deformations of the cycles give rise to a
variety of supersymmetric and metastable non-supersymmetric vacua.Comment: 21 Pages, Latex, 8 Figure
Consistent Interactions between Gauge Fields and Local BRST Cohomology : The Example of Yang-Mills Models
Recent results on the cohomological reformulation of the problem of
consistent interactions between gauge fields are illustrated in the case of the
Yang-Mills models. By evaluating the local BRST cohomology through descent
equation techniques, it is shown (i) that there is a unique local, Poincar\'e
invariant cubic vertex for free gauge vector fields which preserves the number
of gauge symmetries to first order in the coupling constant; and (ii) that
consistency to second order in the coupling constant requires the structure
constants appearing in the cubic vertex to fulfill the Jacobi identity. The
known uniqueness of the Yang-Mills coupling is therefore rederived through
cohomological arguments.Comment: 6 pages in LaTeX, ULB-PMIF/930
Puzzles for Matrix Models of Chiral Field Theories
We summarize the field-theory/matrix model correspondence for a chiral N=1
model with matter in the adjoint, antisymmetric and conjugate symmetric
representations as well as eight fundamentals to cancel the chiral anomaly. The
associated holomorphic matrix model is consistent only for two fundamental
fields, which requires a modification of the original Dijkgraaf-Vafa
conjecture. The modified correspondence holds in spite of this mismatch.Comment: Contribution to the proceedings of the 36th International Symposium
Ahrenshoop, Berlin, August 26-30, 2003; 6 Page
Lumps and P-branes in Open String Field Theory
We describe numerical methods for constructing lump solutions in open string
field theory. According to Sen, these lumps represent lower dimensional
Dp-Branes and numerical evaluation of their energy can be compared with the
expected value for the tension. We take particular care of all higher
derivative terms inherent in Witten's version of open string field theory. The
importance of these terms for off shell phenomena is argued in the text.
Detailed numerical calculations done for the case of general brane show
very good agreement with Sen's conjectured value. This gives credence to the
conjecture itself and establishes further the usefulness of Witten's version of
SFT .Comment: 11 pages, 1 figure, 1 table; v2: small typos correcte
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