Related papers: Duality Symmetries and the Type II String Effectiv…
We derive the T-duality transformations that transform a general d=10 solution of the type-IIA string with one isometry to a solution of the type-IIB string with one isometry and vice versa. In contrast to other superstring theories, the…
It has been shown recently that the toroidally compactified type IIB string effective action possesses an SL(2, R) invariance as a consequence of the corresponding symmetry in ten dimensions when the self-dual five-form field strength is…
We discuss the different discrete duality symmetries in six dimensions that act within and between (i) the 10-dimensional heterotic string compactified on $T^4$, (ii) the 10-dimensional Type IIA string compactified on $K3$ and (iii) the…
We review the construction of a manifestly covariant, supersymmetric and SL(2R) invariant action for IIB supergravity in D=10.
We study the ``ordinary'' Scherk-Schwarz dimensional reduction of the bosonic sector of the low energy effective action of a hypothetical M-theory on $S^1 \times S^1 \cong T^2$. We thus obtain the low energy effective actions of type IIA…
Recent studies suggest that applying the Buscher rules to the dimensional reduction of ten-dimensional, one-loop effective actions generate "purely stringy" couplings in nine dimensions that cannot be lifted to a local, covariant form in…
The SL(2,R) invaraint ten dimensional type IIB superstring effective action is compactified on a torus to D spacetime dimensions. The transformation properties of scalar, vector and tensor fields, appearing after the dimensional reduction,…
Type-IIB supersymmetric theories have an SL(2,Z) invariance, known as U-duality, which controls the non-perturbative behavior of the theory. Under SL(2,Z) the supercharges are doublets, implying that the bosonic charges would be singlets or…
Type II superstring theory with mixed Dirichlet and Neumann boundary conditions admit antisymmetric tensors with varying degrees in the spectrum. We show that there exists a family of dual supergravity lagrangians to the $N=2$ type IIA…
We recast the result of our recent computation of the quartic action of ten-dimensional IIB supergravity in a manifestly SL(2,R)-covariant form. This affords us a critical assessment of an earlier conjecture in the literature.
We use freely acting asymmetric orbifolds of type IIB string theory to construct a class of theories in four dimensions with eight supercharges. Their low energy effective field theories resemble $STU$ models, but have different duality…
The standard eleven-dimensional supergravity action depends on a three-form gauge field and does not allow direct coupling to five-branes. Using previously developed methods, we construct a covariant eleven-dimensional supergravity action…
Duality symmetries in supergravity theories, together with their implications for string theory, are reviewed.
We consider an eleven dimensional supergravity compactified on $K3\times T^2$ and show that the resulting five dimensional theory has identical massless states as that of heterotic string compactified on a specific five torus $T^5$. The…
To the full order in fermions, we construct D=10 type II supersymmetric double field theory. We spell the precise N=2 supersymmetry transformation rules as for 32 supercharges. The constructed action unifies type IIA and IIB supergravities…
We calculate the background field equations for the T-duality symmetric string building on previous work by including the effect of the Dilaton up to two-loops. Inclusion of the Dilaton allows us to obtain the full beta functionals of the…
It is shown in a quantum-mechanically exact manner that a supersymmetric and $\kappa$-symmetric D-string action in a general type IIB supergravity background is transformed to a form of the type IIB Green-Schwarz superstring action with the…
The strong coupling dynamics of string theories in dimension $d\geq 4$ are studied. It is argued, among other things, that eleven-dimensional supergravity arises as a low energy limit of the ten-dimensional Type IIA superstring, and that a…
We reduce the dual version of $D=10$, $N=1$ supergravity coupled to $n$ vector fields to four dimensions, and derive the $SL(2,R)\times O(6,6+n)$ transformations which leave the equations of motion invariant. For $n=0$ $SL(2,R)$ is also a…
This talk is divided into two parts. The first part reviews some of the duality relationships between superstring theories. These relationships are interpreted as providing evidence for the existence of a unique underlying fundamental…