Related papers: Classical solutions for exotic instantons?
In a previous paper [hep-th/0012251] we proposed a simple class of actions for string field theory around the tachyon vacuum. In this paper we search for classical solutions describing D-branes of different dimensions using the ansatz that…
Several dimensionful parameters needed for model building can be engineered in a certain class of SU(5) F-theory GUTs by adding extra singlet fields which are localized along pairwise intersections of D7-branes. The values of these…
We comment on the D-brane solutions for the boundary H3+ model that have been proposed so far and point out that many more types of D-branes should be considered possible. We start a systematic derivation of the 1/2- and b^{-2}/2-shift…
We consider winding number transitions in the two dimensional O(3) non-linear sigma model, modified by a suitable conformal symmetry breaking term. We discuss the general properties of the relevant instanton solutions which dominate the…
We derive the precise relation between level matching condition and fractional instanton numbers in six dimensional, abelian and supersymmetric orbifolds of E8 x E8 heterotic string theory. The fractional part of the two E8 instanton…
We consider, in 5 dimensions, the low energy effective action induced by heterotic string theory including the leading stringy correction of order alpha'. In the presence of a single positive tension flat brane, and an infinite extra…
We study the compatibility between the $BPST SU(2)$ instanton and the fuzzy four-sphere algebra. By using the projective module point of view as an intermediate step, we are able to identify a non-commutative solution of the matrix model…
We study N=2 supersymmetric Abelian gauge model with the Fayet-Iliopoulos term and an arbitrary number of chiral matter multiplets in two dimensions. By analyzing the instanton contribution we compute the non-perturbative corrections to the…
We investigate exotic supergravity theories in 6D with maximal (4,0) and (3,1) supersymmetry, which were conjectured by C. Hull to exist and to describe strong coupling limits of ${\cal N}=8$ theories in 5D. These theories involve exotic…
We discuss instantons in dimensions higher than four. A generalized self-dual or anti-self-dual instanton equation in n-dimensions can be defined in terms of a closed (n-4) form $\Omega$ and it was recently employed as a topological gauge…
We discuss non-perturbative corrections to the gauge kinetic functions in a four-dimensional N=2 gauge theory realized with a system of D7/D3-branes in a compactification of type I' theory on T_4/Z_2 x Z_2. The non-perturbative…
We study new solutions of the low-energy equations of motion for the non-abelian D-string. We find a "fuzzy funnel" solution consisting of a noncommutative four-sphere geometry which expands along the length of the D-string. We show that…
The Exotic Model arises from adding a special exotic invariant to the Supersymmetric Standard Model. The Exotic Model has a supersymmetry violating mass spectrum without using spontaneous or explicit breaking of supersymmetry. The splitting…
For d < 5, we describe an elementary construction of nonzero degree, strict contractions between closed, oriented hyperbolic d-oribifolds. Appealing to work of Gueritaud-Kassel and Tholozan, these examples determine exotic quotients of…
The initial-boundary value problem for the two-dimensional regular four-velocity discrete Boltzmann system is analyzed in a rectangle. The existence and uniqueness of a classical global positive solution, bounded with its first partial…
We study classical solutions (ic-instantons) in N=4 SYM in 4D which, in the strong coupling limit, correspond to complex two-dimensional manifolds. Asymptotically in time the latter have boundaries represented by compact real…
We investigate the differential geometry of the moduli space of instantons on S^3 x S^1. Extending previous results, we show that a sigma-model with this target space can be expected to possess a large N=4 superconformal symmetry,…
We construct $(D-3)$-brane and instanton solutions using $N \le 10-D$ one-form field strengths in $D$ dimensions, and show that the equations of motion can be cast into the form of the $SL(N+1,R)$ Toda equations. For generic values of the…
We study the instanton calculus for N=4 super Yang-Mills theory in ten-dimensional Omega-background with the R-symmetry Wilson line gauge field. From the ADHM construction of instantons in the background, we obtain the deformed instanton…
We suggest a dynamical mechanism which explains why in the supersymmetric IKKT matrix model the $SO(9)$ symmetry of the Lagrangian is spontaneously broken to $SO(3) \times SO(6)$, allowing only three large classical spatial dimensions to…