The geometry of extended null supersymmetry in M-theory

For supersymmetric spacetimes in eleven dimensions admitting a null Killing spinor, a set of explicit necessary and sufficient conditions for the existence of any number of arbitrary additional Killing spinors is derived. The necessary and sufficient conditions are comprised of algebraic relationships, linear in the spinorial components, between the spinorial components and their first derivatives, and the components of the spin connection and four-form. The integrability conditions for the Killing spinor equation are also analysed in detail, to determine which components of the field equations are implied by arbitrary additional supersymmetries and the four-form Bianchi identity. This provides a complete formalism for the systematic and exhaustive investigation of all spacetimes with extended null supersymmetry in eleven dimensions. The formalism is employed to show that the general bosonic solution of eleven dimensional supergravity admitting a $G_2$ structure defined by four Killing spinors is either locally the direct product of $\mathbb{R}^{1,3}$ with a seven-manifold of $G_2$ holonomy, or locally the Freund-Rubin direct product of $AdS_4$ with a seven-manifold of weak $G_2$ holonomy. In addition, all supersymmetric spacetimes admitting a $(G_2\ltimes\mathbb{R}^7)\times\mathbb{R}^2$ structure are classified.Comment: 36 pages, latex; v2, section classifying all spacetimes admitting a $(G_2\ltimes\mathbb{R}^7)\times\mathbb{R}^2$ structure included; v3, typos corrected. Final version to appear in Phys.Rev.

Nearing Extremal Intersecting Giants and New Decoupled Sectors in N = 4 SYM

We study near-horizon limits of near-extremal charged black hole solutions to five-dimensional $U(1)^3$ gauged supergravity carrying two charges, extending the recent work of Balasubramanian et.al. We show that there are two near-horizon decoupling limits for the near-extremal black holes, one corresponding to the near-BPS case and the other for the far from BPS case. Both of these limits are only defined on the 10d IIB uplift of the 5d black holes, resulting in a decoupled geometry with a six-dimensional part (conformal to) a rotating BTZ X $S^3$. We study various aspects of these decoupling limits both from the gravity side and the dual field theory side. For the latter we argue that there should be two different, but equivalent, dual gauge theory descriptions, one in terms of the 2d CFT's dual to the rotating BTZ and the other as certain large R-charge sectors of d=4,N =4 U(N) SYM theory. We discuss new BMN-type sectors of the N=4 SYM in the $N\to\infty$ limit in which the engineering dimensions scale as $N^{3/2}$ (for the near-BPS case) and as $N^2$ (for the far from BPS case).Comment: 44 pages, references added, minor change

On the smoothness of multi-M2 brane horizons

We calculate the degree of horizon smoothness of multi- $M2$-brane solution with branes along a common axis. We find that the metric is generically only thrice continuously differentiable at any of the horizons. The four-form field strength is found to be only twice continuously differentiable. We work with Gaussian null-like co-ordinates which are obtained by solving geodesic equations for multi-$M2$ brane geometry. We also find different, exact co-ordinate transformations which take the metric from isotropic co-ordinates to co-ordinates in which metric is thrice differentiable at the horizon. Both methods give the same result that the multi-$M2$ brane metric is only thrice continuously differentiable at the horizon.Comment: 24 pages, reference added, modified equation for non-singularity of metri

The complex geometry of holographic flows of quiver gauge theories

We argue that the complete Klebanov-Witten flow solution must be described by a Calabi-Yau metric on the conifold, interpolating between the orbifold at infinity and the cone over T^(1,1) in the interior. We show that the complete flow solution is characterized completely by a single, simple, quasi-linear, second order PDE, or "master equation," in two variables. We show that the Pilch-Warner flow solution is almost Calabi-Yau: It has a complex structure, a hermitian metric, and a holomorphic (3,0)-form that is a square root of the volume form. It is, however, not Kahler. We discuss the relationship between the master equation derived here for Calabi-Yau geometries and such equations encountered elsewhere and that govern supersymmetric backgrounds with multiple, independent fluxes.Comment: 26 pages, harvmac + amssy

Splitting hairs of the three charge black hole

We construct the large radius limit of the metric of three charge supertubes and three charge BPS black rings by using the fact that supertubes preserve the same supersymmetries as their component branes. Our solutions reproduce a few of the properties of three charge supertubes found recently using the Born Infeld description. Moreover, we find that these solutions pass a number of rather nontrivial tests which they should pass if they are to describe some of the hair of three charge black holes and three charge black rings.Comment: 15 pages, LaTeX, v2 minor correction

Are There Any New Vacua of Gauged N=8 Supergravity in Four Dimensions?

We consider the most general SU(3) singlet space of gauged N=8 supergravity in four-dimensions. The SU(3)-invariant six scalar fields in the theory can be viewed in terms of six real four-forms. By exponentiating these four-forms, we eventually obtain the new scalar potential. For the two extreme limits, we reproduce the previous results found by Warner in 1983. In particular, for the N=1 G_2 critical point, we find the constraint surface parametrized by three scalar fields on which the cosmological constant has the same value. We obtain the BPS domain-wall solutions for restricted scalar submanifold. We also describe the three-dimensional mass-deformed superconformal Chern-Simons matter theory dual to the above supersymmetric flows in four-dimensions.Comment: 44p; the main text and appendices improved for compact presentation;the acknowledgments added and to appear in IJMP

Symplectic potentials and resolved Ricci-flat ACG metrics

We pursue the symplectic description of toric Kahler manifolds. There exists a general local classification of metrics on toric Kahler manifolds equipped with Hamiltonian two-forms due to Apostolov, Calderbank and Gauduchon(ACG). We derive the symplectic potential for these metrics. Using a method due to Abreu, we relate the symplectic potential to the canonical potential written by Guillemin. This enables us to recover the moment polytope associated with metrics and we thus obtain global information about the metric. We illustrate these general considerations by focusing on six-dimensional Ricci flat metrics and obtain Ricci flat metrics associated with real cones over L^{pqr} and Y^{pq} manifolds. The metrics associated with cones over Y^{pq} manifolds turn out to be partially resolved with two blowup parameters taking special (non-zero)values. For a fixed Y^{pq} manifold, we find explicit metrics for several inequivalent blow-ups parametrised by a natural number k in the range 0<k<p. We also show that all known examples of resolved metrics such as the resolved conifold and the resolution of C^3/Z_3 also fit the ACG classification.Comment: LaTeX, 34 pages, 4 figures (v2)presentation improved, typos corrected and references added (v3)matches published versio

N=8 Gauged Supergravity Theory and N=6 Superconformal Chern-Simons Matter Theory

By studying the previously known holographic N=4 supersymmetric renormalization group flow(Gowdigere-Warner) in four dimensions, we find the mass deformed Chern-Simons matter theory which has N=4 supersymmetry by adding the four mass terms among eight adjoint fields. The geometric superpotential from the eleven dimensions is found and provides the M2-brane probe analysis. As second example, we consider known holographic N=8 supersymmetric renormalization group flow(Pope-Warner) in four dimensions. The eight mass terms are added and similar geometric superpotential is obtained.Comment: 39 pp; The footnotes 3 and 4 and the ref. added; improved the page 2 and to appear in IJMP

Consistent truncation of d = 11 supergravity on AdS_4 x S^7

We study the system of equations derived twenty five years ago by B. de Wit and the first author [Nucl. Phys. B281 (1987) 211] as conditions for the consistent truncation of eleven-dimensional supergravity on AdS_4 x S^7 to gauged N = 8 supergravity in four dimensions. By exploiting the E_7(7) symmetry, we determine the most general solution to this system at each point on the coset space E_7(7)/SU(8). We show that invariants of the general solution are given by the fluxes in eleven-dimensional supergravity. This allows us to both clarify the explicit non-linear ansatze for the fluxes given previously and to fill a gap in the original proof of the consistent truncation. These results are illustrated with several examples.Comment: 41 pages, typos corrected, published versio

Deformations of flows from type IIB supergravity

We consider supersymmetric SL(3,R) deformations of various type IIB supergravity backgrounds which exhibit flows away from an asymptotically locally AdS_5 x S^5 fixed point. This includes the gravity dual of the Coulomb branch of N=1 super Yang Mills theory, for which the deformed superpotential is known. We also consider the gravity duals of field theories which live on various curved backgrounds, such as Minkowski_2 x H^2, AdS_3 x S^1 and R x S^3. Some of the deformed theories flow from a four-dimensional N=1 superconformal UV fixed point to a two-dimensional (2,2) superconformal IR fixed point. We study nonsupersymmetric generalizations of the deformations of the above Coulomb branch flows.Comment: 29 pages, additional references and comment