Stable Non-Supersymmetric Vacua in the Moduli Space of Non-Critical Superstrings

We study a set of asymmetric deformations of non-critical superstring theories in various dimensions. The deformations arise as Kaehler and complex structure deformations of an orthogonal two-torus comprising of a parallel and a transverse direction in the near-horizon geometry of NS5-branes. The resulting theories have the following intriguing features: Spacetime supersymmetry is broken in a continuous fashion and the masses of the lightest modes are lifted. In particular, no bulk or localized tachyons are generated in the non-supersymmetric vacua. We discuss the effects of these deformations in the context of the holographic duality between non-critical superstrings and Little String Theories and find solutions of rotating fivebranes in supergravity. We also comment on the generation of a one-loop cosmological constant and determine the effects of the one-loop backreaction to leading order.Comment: lanlmac, 41 pages, 1 figure; v2 an erroneous statement corrected in section 6, version published in NP

Brane Dynamics and 3D Seiberg Duality on the Domain Walls of 4D N=1 SYM

We study a three-dimensional U(k) Yang-Mills Chern-Simons theory with adjoint matter preserving two supersymmetries. According to Acharya and Vafa, this theory describes the low-energy worldvolume dynamics of BPS domain walls in four-dimensional N=1 SYM theory. We demonstrate how to obtain the same theory in a brane configuration of type IIB string theory that contains threebranes and fivebranes. A combination of string and field theory techniques allows us to re-formulate some of the well-known properties of N=1 SYM domain walls in a geometric language and to postulate a Seiberg-like duality for the Acharya-Vafa theory. In the process, we obtain new information about the dynamics of branes in setups that preserve two supersymmetries. Using similar methods we also study other N=1 CS theories with extra matter in the adjoint and fundamental representations of the gauge group.Comment: 25 pages, 5 figure

World-Volume Effective Theory for Higher-Dimensional Black Holes

We argue that the main feature behind novel properties of higher-dimensional black holes, compared to four-dimensional ones, is that their horizons can have two characteristic lengths of very different size. We develop a long-distance worldvolume effective theory that captures the black hole dynamics at scales much larger than the short scale. In this limit the black hole is regarded as a blackfold: a black brane (possibly boosted locally) whose worldvolume spans a curved submanifold of the spacetime. This approach reveals black objects with novel horizon geometries and topologies more complex than the black ring, but more generally it provides a new organizing framework for the dynamics of higher-dimensional black holes.Comment: 11 pages. v2: title changed to match published version in PRL; otherwise minor correction

Comments on F-maximization and R-symmetry in 3D SCFTs

We report preliminary results on the recently proposed F-maximization principle in 3D SCFTs. We compute numerically in the large-N limit the free energy on the three-sphere of an N=2 Chern-Simons-Matter theory with a single adjoint chiral superfield which is known to exhibit a pattern of accidental symmetries associated to chiral superfields that hit the unitarity bound and become free. We observe that the F-maximization principle produces a U(1) R-symmetry consistent with previously obtained bounds but inconsistent with a postulated Seiberg-like duality. Potential modifications of the principle associated to the decoupling fields do not appear to be sufficient to account for the observed violations.Comment: 17 pages, 3 figures; v2 a reference has been added, a missing factor of 2 has been corrected in eq (3.3) and the numerical results have been accordingly updated. The new results do not show any obvious signs of violation of previously obtained bounds. A potential disagreement with a postulated Seiberg-like duality is note

The Phase Structure of Higher-Dimensional Black Rings and Black Holes

We construct an approximate solution for an asymptotically flat, neutral, thin rotating black ring in any dimension D>=5 by matching the near-horizon solution for a bent boosted black string, to a linearized gravity solution away from the horizon. The rotating black ring solution has a regular horizon of topology S^1 x S^{D-3} and incorporates the balancing condition of the ring as a zero-tension condition. For D=5 our method reproduces the thin ring limit of the exact black ring solution. For D>=6 we show that the black ring has a higher entropy than the Myers-Perry black hole in the ultra-spinning regime. By exploiting the correspondence between ultra-spinning black holes and black membranes on a two-torus, we take steps towards qualitatively completing the phase diagram of rotating blackfolds with a single angular momentum. We are led to propose a connection between MP black holes and black rings, and between MP black holes and black Saturns, through merger transitions involving two kinds of `pinched' black holes. More generally, the analogy suggests an infinite number of pinched black holes of spherical topology leading to a complicated pattern of connections and mergers between phases.Comment: 61 pages, 6 figures, latex. v2: Added refs., typos corrected, improved section 8. v3: minor changes, version appearing in JHE