Mark B Stern

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We study the existence of D-brane bound states at threshold in Type II string theories. In a number of situations, we can reduce the question of existence to quadrature, and the study of a particular limit of the propagator for the system of D-branes. This involves a derivation of an index theorem for a family of non-Fredholm operators. In support of the(More)
We count the supersymmetric bound states of many distinct BPS monopoles in N = 4 Yang-Mills theories and in pure N = 2 Yang-Mills theories. The novelty here is that we work in generic Coulombic vacua where more than one adjoint Higgs fields are turned on. The number of purely magnetic bound states is again found to be consistent with the electromagnetic(More)
Cheeger, Goresky, and MacPherson conjectured [CGM] an L2-de Rham theorem: that the intersection cohomology of a projective variety V is naturally isomorphic to the L2cohomology of the incomplete manifold V − Sing V , with metric induced by a projective embedding. The early interest in this conjecture was motivated in large part by the hope that one could(More)
BACKGROUND Management of fecal incontinence is a priority in acute and critical care to reduce risk of perineal dermatitis and transmission of nosocomial infections. OBJECTIVE To evaluate the safety of the Flexi-Seal Fecal Management System in hospitalized patients with diarrhea and incontinence. METHODS A prospective, single-arm clinical study with 42(More)
Higher derivative terms in the effective action of certain Yang-Mills theories can be severely constrained by supersymmetry. We show that requiring sixteen supersymmetries in quantum mechanical gauge theory determines the v 6 term in the effective action. Even the numerical coefficient of the v 6 term is fixed in terms of lower derivative terms in the(More)
We study the extent to which the gauge symmetry of abelian Yang-Mills can be deformed under two conditions: first, that the deformation depend on a two-form scale. Second, that the deformation preserve supersymmetry. We show that (up to a single parameter) the only allowed deformation is the one determined by the star product. We then consider the(More)