Browsing by Author "Poghossian, Rubik"

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    Instanton counting on Hirzebruch surfaces
    (2008-09-05T18:06:43Z) Bruzzo, Ugo; Poghossian, Rubik; Tanzini, Alessandro; Mathematics; Mathematical Physics
    We perform a study of the moduli space of framed torsion free sheaves on Hirzebruch surfaces by using localization techniques. After discussing general properties of this moduli space, we classify its fixed points under the appropriate toric action and compute its Poincare' polynomial. From the physical viewpoint, our results provide the partition function of N=4 Vafa-Witten theory on Hirzebruch surfaces, which is relevant in black hole entropy counting problems according to a conjecture due to Ooguri, Strominger and Vafa.
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    N=1 superpotentials from multi-instanton calculus
    (2005) Fucito, Francesco; Morales, Jose F.; Poghossian, Rubik; Tanzini, Alessandro; Mathematics; Mathematical Physics
    In this paper we compute gaugino and scalar condensates in N = 1 supersymmetric gauge theories with and without massive adjoint matter, using localization formulae over the multi-instanton moduli space. Furthermore we compute the chiral ring relations among the correlators of the N = 1* theory and check this result against the multi-instanton computation finding agreement.