Related papers: D2-D8 system with massive strings and the Lifshitz…
We consider massive type IIA compactifications down to 4 dimensions in presence of O6 planes and D6 branes parallel to them, in order to preserve half-maximal supersymmetry in 4D. The dynamics of open strings living on the spacetime filling…
In this paper we study $T^2$ compactification of 6-dimensional massive type IIA supergravity in presence of Ramond-Ramond background fluxes. The resulting theory in four dimensions is shown to possess $SL(2,R)\times SL(2,R)\times O(4,20)$…
We present two new solutions of Romans' massive type IIA supergravity characterized by the two non-trivial massive potentials of Romans' theory: the NSNS 2-form and the RR 7-form. They can be interpreted respectively as the intersection of…
We study $T^2$ compactification of massive type IIA supergravity in presence of possible Ramond-Ramond (RR) background fluxes. The resulting theory in D=8 is shown to possess full $SL(2,R)\times SL(2,R)$ T-duality symmetry similar to the…
The massive IIA string theory whose low energy limit is the massive supergravity theory constructed by Romans is obtained from M-theory compactified on a 2-torus bundle over a circle in a limit in which the volume of the bundle shrinks to…
We study type IIA string theory compactified on Calabi-Yau fourfolds and heterotic string theory compactified on Calabi-Yau threefolds times a two-torus. We derive the resulting effective theories which have two space-time dimensions and…
In this paper we perform a detailed investigation of the Dirichlet eight-brane of the Type IIA string theory, when the effects of gravity are included. In particular, consider what happens when one allows the ten-form field strength…
Type-IIB supergravity in ten dimensions admits two consistent $Z_2$ truncations. After the insertion of D9-branes, one of them leads to the low-energy action of type-I string theory, and it can be performed in two different ways, in…
We construct, following \cite{mpgm14,mpgm17}, a massive M2-brane (supermembrane) as the limit of a genus two M2-brane that becomes a twice punctured Riemann surface with particular boundary conditions on the fields defined on the punctures.…
We show that all supersymmetric Type IIA D-branes can be constructed as bound states of a certain number of unstable non-supersymmetric Type IIA D9-branes. This string-theoretical construction demonstrates that D-brane charges in Type IIA…
We construct dual Type I' string descriptions to five dimensional supersymmetric fixed points with $E_{N_f+1}$ global symmetry. The background is obtained as the near horizon geometry of the D4-D8 brane system in massive Type IIA…
Motivated by the M-theory compactification physics, we study a type IIA superstring quiver model with an open string axion field associated with the U(1)_{PQ} Peccei-Quinn global symmetry using D6-brane physics. This realization extends the…
We study the D8-branes of the Romans massive IIA supergravity theory using the coupled supergravity and worldvolume actions. D8 branes can be regarded as domain walls with the jump in the extrinsic curvature at the brane given by the Israel…
We find novel bound states of NS5, D6 and D8-branes in massive Type IIA string theory. As the NS gauge transformations can change the Chern class of the RR field these configurations should be thought of as nonlocal objects called gerbes.…
Matrix string theory is equivalent to type IIA superstring theory in the light-cone gauge, together with extra degrees of freedom representing D-brane states. It is therefore the appropriate framework in which to study systems of multiple…
Looking for string vacua with fixed moduli, we study compactifications of type IIA string theory on Calabi-Yau fourfolds in the presence of generic Ramond-Ramond fields. We explicitly derive the (super)potential induced by Ramond-Ramond…
We discuss a generalized form of IIA/IIB supergravity depending on all R-R potentials C^(p) (p=0,1,...,9) as the effective field theory of Type IIA/IIB superstring theory. For the IIA case we explicitly break this R-R democracy to either…
We review the prospect of obtaining tree-level de Sitter (dS) vacua and slow-roll inflation models in string compactifications. Restricting ourselves to the closed string sector and assuming the absence of NSNS-sources, we classify the…
We propose a unified framework within Type IIA string theory, based on a globally consistent intersecting D6-brane model compactified on a $T^6/(\mathbb{Z}_2 \times \mathbb{Z}_2)$ orientifold. The model realizes the MSSM-like spectrum…
In this paper, we study the implementation of brane worlds in type II string theory. Starting with the NS/NS sector of type II string, we first compactify the $(D+d_{+} + d_{-})$-dimensional spacetime, and reduce the corresponding action to…