相关论文: Closed string tachyons, flips and conifolds

We find an interesting connection between perturbative large N gauge theory and closed superstrings. The gauge theory in question is found on N D3-branes placed at the tip of the cone R^6/Gamma. In our previous work we showed that, when the…

Motivated by the smallness of the cosmological constant we investigate whether it is possible to have vanishing one-loop heterotic string partition functions for six-dimensional non-supersymmetric toroidal orbifolds. A straightforward way…

We study the localized tachyon condensation in their mirror Landau-Ginzburg picture. We completely determine the decay mode of an unstable orbifold $C^r/Z_n$, $r=1,2,3$ under the condensation of a tachyon with definite R-charge and mass by…

In this short note we present a mathematical interpretation of tachyon condensation on (three dimensional) orbifolds within the framework of boundary string field theory (BSFT). We explicitly show that important parts of decay modes in…

We provide the first holographic evidence for the existence of a non-supersymmetric conformal manifold arising from exactly marginal but supersymmetry-breaking deformations of a superconformal three-dimensional field theory. In particular,…

We study a topological obstruction of a very stringy nature concerned with deforming the target space of an $N=2$ non-linear \sm. This target space has a singularity which may be smoothed away according to the conventional rules of geometry…

We study closed string tachyon condensation using the RG flow of the worldsheet theory. In many cases the worldsheet theory enjoys N=2 supersymmetry, which provides analytic control over the flow, due to non-renormalization theorems.…

The worldsheet renormalization group approach to tachyon condensation in string theory is reviewed. The open string case is summarized with examples, and closed string tachyon condensation on nonsupersymmetric orbifolds is examined in…

In this paper we explicitly show that the various noncompact abelian orbifolds are realized as special limits of parameters in type II (NSNS) Melvin background and its higher dimensional generalizations. As a result the supersymmetric ALE…

We investigate deformations of $\mathbb{Z}_2$ orbifold singularities on the toroidal orbifold $T^6/(\mathbb{Z}_2\times\mathbb{Z}_6)$ with discrete torsion in the framework of Type IIA orientifold model building with intersecting D6-branes…

We study $E_8 \times E_8$-heterotic string on asymmetric orbifolds associated with semi-simple simply-laced Lie algebras. Using the fact that $E_6$-model allows different twists, we present a new N=1 space-time supersymmetric model whose…

We construct a nonperturbative regularization for Euclidean noncommutative supersymmetric Yang-Mills theories with four (N= (2,2)), eight (N= (4,4)) and sixteen (N= (8,8)) supercharges in two dimensions. The construction relies on orbifolds…

We review several mechanisms for supersymmetry breaking in orientifold models. In particular, we focus on non-supersymmetric open-string realisations that correspond to consistent flat-space solutions of the classical equations of motion.…

We provide a detailed study of the phenomenology of orbifold compactifications of the heterotic string within the context of supergravity effective theories. Our investigation focuses on those models where the soft Lagrangian is dominated…

Multiply-connected Calabi-Yau threefolds are of particular interest for both string theorists and mathematicians. Recently it was pointed out that one of the generic degenerations of these spaces (occurring at codimension one in moduli…

We investigate how the marginal deformations of N=4 supersymmetric Yang-Mills theory (analysed in particular by Leigh and Strassler) arise within B-model topological string theory on supertwistor space CP(3|4). This is achieved by turning…

When supersymmetry is spontaneously broken at tree level, the spectrum of the heterotic string compactified on orbifolds of tori contains an infinite number of potentially tachyonic modes. We show that this implies instabilities of…

I argue that the ten dimensional non--supersymmetric tachyonic superstrings may serve as good starting points for the construction of viable phenomenological vacua. Thus, enlarging the space of possible solutions that may address some of…

We study Ricci-flat deformations of orbifolds in type II theory. We obtain a simple formula for mass corrections to the twisted modes due to the deformations, and apply it to originally tachyonic and massless states in several examples. In…

We conjecture a topology changing transition in M-theory on a non-compact asymptotically conical Spin(7) manifold, where a 5-sphere collapses and a CP(2) bolt grows. We argue that the transition may be understood as the condensation of…