1,721,024 research outputs found
Superlocalization formulas and supersymmetric Yang-Mills theories
Full text linkBy using supermanifold techniques we prove a generalization of the localization formula in equivariant cohomology which is suitable for studying supersymmetric Yang-Mills theories in terms of ADHM data. With these techniques one can compute the reduced partition functions of topological super Yang-Mills theory with 4, 8 or 16 supercharges. More generally, the superlocalization formula can be applied to any topological field theory in any number of dimensions
Non-perturbative two-dimensional quantum gravity, KdV Hierarchy and solutions of the string equations
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D-instanton probes of non-conformal geometries
No full textD-instanton calculus has proved to be able to probe the AdS near horizon geometry for N D-branes systems which, when decoupled from gravity, yield four-dimensional superconformal gauge theories with various matter content. In this work we extend previous analysis to encompass fractional brane models which give rise to non-conformal N = 2 Super Yang-Mills theories. Via D-instanton calculus we study the geometry of such models for finite N and recover the beta function of the gauge coupling constants which is expected in non-conformal gauge theories. We also give a topological matrix theory formulation for the D-instanton action of these theories. Finally, we revisit the related system where the D3-branes wrap a R-4/Z(p) orbifold singularity and the D(-1)-branes are associated to instanton solutions of four-dimensional gauge theories in the blown down ALE space
Multi - instantons, supersymmetry and topological field theories
Full text linkIn this letter we argue that instanton-dominated Green's functions in N=2 Super Yang-Mills theories can be equivalently computed either using the so-called constrained instanton method or making reference to the topological twisted version of the theory. Defining an appropriate BRST operator (as a supersymmetry plus a gauge variation), we also show that the expansion coefficients of the Seiberg-Witten effective action for the low-energy degrees of freedom can be written as integrals of total derivatives over the moduli space of self-dual gauge connections
Quantum Models of Black Hole Evaporation
Full text linkThe discovery of black-hole evaporation represented in many respects a
revolutionary event in scientific world; as such, in giving answers to open
questions, it gave rise to new problems part of which are still not resolved.
Here we want to make a brief review of such problems and examine some possible
solutions. Invited Talk at the "Workshop on String Theory, Quantum Gravity and
the Unification of the Fundamental Interactions" Rome, September 21-26Comment: 9 pages, ROM2F-92/6
D-brane instantons on the T^6 / Z(3) orientifold
No full textWe give a detailed microscopic derivation of gauge and stringy instanton gen erated superpotentials for gauge theories living on D3-branes at Z(3)-orientifold singularities. Gauge instantons are generated by D(-1)-branes and lead to Affleck, Dine and Seiberg (ADS) like superpotentials in the effective N = 1 gauge theories with three generations of bifundamental and anti/symmetricmatter.Stringy instanton effects are generated by Euclidean ED3-branes wrapping four cycles onT(6)/Z(3).They give rise to Majorana masses,Yukawa couplings or non-renormalizable superpotentials depending on the gauge theory.Finally we determine the conditions under which ADS like superpotentials are generated in N = 1gauge theories with adjoints, fundamentals, symmetric and antisymmetric chiral matter
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