The complete spectrum of D = 6, N = 4b supergravity with n tensor multiplets compactified on AdS 3 × S 3 is determined. The D = 6 theory obtained from the K 3 compactification of Type IIB string requires that n = 21, but we let n be arbitrary. The superalgebra that underlies the symmetry of the resulting supergravity theory in AdS 3 coupled to matter is SU (1, 1|2) L × SU (1, 1|2) R . The theory also has an unbroken global SO(4) R × SO(n) symmetry inherited from D = 6. The spectrum of states arranges itself into a tower of spin 2 supermultiplets, a tower of spin 1, SO(n) singlet supermultiplets, a tower of spin 1 supermultiplets in the vector representation of SO(n) and a special spin 1 2 supermultiplet also in the vector representation of SO(n). The SU (2) L × SU (2) R Yang-Mills states reside in the second level of the spin 2 tower and the lowest level of the spin 1, SO(n) singlet tower and the associated field theory exhibits interesting properties.

We couple n copies of N = (2, 0) scalar multiplets to a gauged N = (2, 0) supergravity in 2 + 1 dimensions which admits AdS 3 as a vacuum. The scalar fields are charged under the gauged R-symmetry group U (1) and parametrize certain Kahler manifolds with compact or noncompact isometries. The radii of these manifolds are quantized in the compact case, but arbitrary otherwise. In the compact case, we find half-supersymmetry preserving and asymptotically Minkowskian black string solutions. For a particular value of the scalar manifold radius, the solution coincides with that of Horne and Horowitz found in the context of a string theory in 2 + 1 dimensions. In the non-compact case, we find half-supersymmetry preserving and asymptotically AdS 3 string solutions which have naked singularities. We also obtain two distinct AdS 3 supergravities coupled to n copies of N = (1, 0) scalar multiplets either by the truncation of the (2, 0) model or by a direct construction.

We construct all possible orthogonally intersecting S-brane solutions in 11-dimensions corresponding to standard supersymmetric M-brane intersections. It is found that the solutions can be obtained by multiplying the brane and the transverse directions with appropriate powers of two hyperbolic functions of time. This is the S-brane analog of the "harmonic function rule". The transverse directions can be hyperbolic, flat or spherical. We also discuss some properties of these solutions. 1

We present a cosmological model in 1 + m + p dimensions, where in m-dimensional space there are uniformly distributed p-branes wrapping over the extra p-dimensions. We find that during cosmological evolution m-dimensional space expands with the exact power-law corresponding to pressureless matter while the extra p-dimensions contract. Adding matter, we also obtain solutions having the same property. We show that this might explain in a natural way why the extra dimensions are small compared to the observed three spatial directions. *

We determine the most general form of off-shell N = (1, 1) supergravity field configurations in three dimensions by requiring that at least one off-shell Killing spinor exists. We then impose the field equations of the topologically massive off-shell supergravity and find a class of solutions whose properties crucially depend on the norm of the auxiliary vector field. These are spacelike-squashed and timelike-stretched AdS 3 for the spacelike and timelike norms, respectively. At the transition point where the norm vanishes, the solution is null warped AdS 3 . This occurs when the coefficient of the Lorentz-Chern-Simons term is related to the AdS radius by µ = 2. We find that the spacelike-squashed AdS 3 can be modded out by a suitable discrete subgroup of the isometry group, yielding an extremal black hole solution which avoids closed timelike curves. arXiv:1311.4583v2 [hep-th]