No Arabic abstract
We analyze the exact perturbative solution of N=2 Born-Infeld theory which is believed to be defined by Ketovs equation. This equation can be considered as a truncation of an infinite system of coupled differential equations defining Born-Infeld action with one manifest N=2 and one hidden N=2 supersymmetries. We explicitly demonstrate that infinitely many new structures appear in the higher orders of the perturbative solution to Ketovs equation. Thus, the full solution cannot be represented as a function depending on {it a finite number} of its arguments. We propose a mechanism for generating the new structures in the solution and show how it works up to 18-th order. Finally, we discuss two new superfield actions containing an infinite number of terms and sharing some common features with N=2 supersymmetric Born-Infeld action.
We derive new types of $U(1)^n$ Born-Infeld actions based on N=2 special geometry in four dimensions. As in the single vector multiplet (n=1) case, the non--linear actions originate, in a particular limit, from quadratic expressions in the Maxwell fields. The dynamics is encoded in a set of coefficients $d_{ABC}$ related to the third derivative of the holomorphic prepotential and in an SU(2) triplet of N=2 Fayet-Iliopoulos charges, which must be suitably chosen to preserve a residual N=1 supersymmetry.
We study the Dirac-Born-Infeld (DBI) action with one linear and one non-linear supersymmetry in the presence of a constant Fayet-Iliopoulos (FI) D-term added explicitly or through a deformation of supersymmetry transformations. The linear supersymmetry appears to be spontaneously broken since the D auxiliary field gets a non-vanishing vacuum expectation value and an extra term proportional to the FI parameter involving fermions emerges in the non-linear formulation of the action written recently. However in this note, we show that on-shell this action is equivalent to a standard supersymmetric DBI action ${it without}$ FI term but with redefined tension, at least up to order of mass-dimension 12 effective interactions.
We consider the N=4 supersymmetric Yang-Mills theory in four dimensions. We compute the one-loop contributions to the effective action with five external vector fields and compare them with corresponding results in open superstring theory. Our calculation determines the structure of the F^5 terms that appear in the nonabelian generalization of the Born Infeld action. The trace operation on the gauge group indices receives contributions from the symmetric as well as the antisymmetric part. We find that in order to study corrections to the symmetrized trace prescription one has to consistently take into account derivative contributions not only with antisymmetrized products abla_{[mu} abla_{ u]} but also with symmetrized ones abla_{(mu} abla_{ u)}.
The Hawking-Moss tunneling rate for a field described by the Dirac-Born-Infeld action is calculated using a stochastic approach. We find that the effect of the non-trivial kinetic term is to enhance the tunneling rate, which can be exponentially significant. This result should be compared to the DBI enhancement found in the Coleman-de Luccia case.
We discuss recent results on one-loop contributions to the effective action in {cal N}=4 supersymmetric Yang-Mills theory in four dimensions. Contributions with five external vector fields are compared with corresponding ones in open superstring theory in order to understand the relation with the F^5 terms that appear in the nonabelian generalization of the Born-Infeld action.