Glueball Inflation and Gauge/Gravity Duality

We summarize our work on building glueball inflation models with the methods of the gauge/gravity duality. We review the relevant five-dimensional consistent truncation of type IIB supergravity. We consider solutions of this effective theory, whose metric has the form of a $dS_4$ foliation over a radial direction. By turning on small (in an appropriate sense) time-dependent deformations around these solutions, one can build models of glueball inflation. We discuss a particular deformed solution, describing an ultra-slow roll inflationary regime.Comment: 9 pages, contribution to the proceedings of the 11th international workshop "Lie Theory and its Applications in Physics", Varna, 201

Flux Vacua Attractors and Generalized Compactifications

We investigate whether there are attractor equations for N=1 flux vacua in generalized compactifications. We fill a gap in the existing literature by verifying analytically that the recently proposed susy attractors, for type IIB CY(3) orientifold compactifications with flux, do give supersymmetric minima of the relevant scalar potential. Furthermore, our considerations clarify various confusions about existing proposals for generalization of the flux vacua attractors to non-K\"{a}hler compactifications. We explore different possibilities for generalization and find attractor equations for N=1 Minkowski vacua only both for the heterotic string on SU(3) structure manifolds and for type IIA/B on SU(3)xSU(3) structure spaces.Comment: 39 pages; small improvements and clarifications, references added, journal versio

A Gravity Dual of Ultra-slow Roll Inflation

We study time-dependent deformations of a certain class of backgrounds in type IIB supergravity. These backgrounds are solutions of a five-dimensional consistent truncation, relevant for gauge/gravity duality, which have the form of dS_4 foliations over a fifth (radial) direction. We investigate time-dependent deformations of those solutions in the search for gravitational duals of models of glueball inflation. A particular starting ansatz enables us to find a class of analytical solutions, corresponding to an ultra-slow roll inflationary regime. This regime may play a role in understanding the low l anomaly in the power spectrum of the CMB.Comment: 27 pages; explanations and references added, journal versio

Flux Superpotential in Heterotic M-theory

We derive the most general flux-induced superpotential for N=1 M-theory compactifications on seven-dimensional manifolds with SU(3) structure. Imposing the appropriate boundary conditions, this result applies for heterotic M-theory. It is crucial for the latter to consider SU(3) and not G_2 group structure on the seven-dimensional internal space. For a particular background that differs from CY(3) x S^1/Z_2 only by warp factors, we investigate the flux-generated scalar potential as a function of the orbifold length. We find a positive cosmological constant minimum, however at an undesirably large value of this length. Hence the flux superpotential alone is not enough to stabilize the orbifold length at a de Sitter vacuum. But it does modify substantially the interplay between the previously studied non-perturbative effects, possibly reducing the significance of open membrane instantons while underlining the importance of gaugino condensation.Comment: 33 pages; minor clarifications, reference adde

Hyperkahler Cones and Orthogonal Wolf Spaces

We construct the hyperkahler cones corresponding to the Quaternion-Kahler orthogonal Wolf spaces SO(n+4)/(SO(n)xSO(4)) and their non-compact versions, which appear in hypermultiplet couplings to N=2 supergravity. The geometry is completely encoded by a single function, the hyperkahler potential, which we compute from an SU(2) hyperkahler quotient of flat space. We derive the Killing vectors and moment maps for the SO(n+4) isometry group on the hyperkahler cone. For the non-compact case, the isometry group SO(n,4) contains n+2 abelian isometries which can be used to find a dual description in terms of n tensor multiplets and one double-tensor multiplet. Finally, using a representation of the hyperkahler quotient via quiver diagrams, we deduce the existence of a new eight dimensional ALE space.Comment: 19 pages, Latex, 2 figures (references added

The Leading Quantum Corrections to Stringy Kahler Potentials

The structure of stringy quantum corrections to four-dimensional effective theories is particularly interesting for string phenomenology and attempts to stabilize moduli. We consider the heterotic string compactified on a Calabi-Yau space. For this case, we compute the leading corrections to the kinetic terms of moduli fields. The structure of these corrections is largely dictated by the underlying higher-dimensional extended supersymmetry. We find corrections generically of order (alpha')^2 rather than of order (alpha')^3 found in type II compactifications or heterotic compactifications with the standard embedding. We explore the implications of these corrections for breaking no-scale structure.Comment: 33 pages, LaTeX; modified section

Stability of D-brane embeddings in nontrivial backgrounds

We propose a new analytical method for determining whether nonsupersymmetric probe branes embedded in nontrivial backgrounds are perturbatively stable or not. The method is based on a relationship between zero mass solutions of the relevant DBI equations of motion and tachyonic solutions. Furthermore, due to the above relation, the question, of whether a classical solution is stable or not, can be answered simply by studying the derivatives of that solution with respect to its integration constants. Finally, we illustrate the efficiency of this method by applying it to several interesting examples.Comment: 18 pages; introductory material added in Section 2, journal versio