Greybody Factors and Charges in Kerr/CFT

We compute greybody factors for near extreme Kerr black holes in D=4 and D=5. In D=4 we include four charges so that our solutions can be continuously deformed to the BPS limit. In D=5 we include two independent angular momenta so Left-Right symmetry is incorporated. We discuss the CFT interpretation of our emission amplitudes, including the overall frequency dependence and the dependence on all black hole parameters. We find that all additional parameters can be incorporated Kerr/CFT, with central charge independent of U(1) charges.Comment: 27 pages. v2: typos fixed, references adde

Gravitational couplings of orientifold planes

We reanalyse the gravitational couplings of the perturbative orientifold planes $Op^-$, $Op^+$ (and D-branes). We first compute their $D_{-1}$ instantonic corrections for $p=3$. Then, by using U-dualities, we obtain the Wess-Zumino terms of orientifolds with RR flux for $p \leq 5$. The expressions for the effective actions can be partially checked via M-theory. We point out a previous oversimplification and we show in fact that the difficulty still stands in the way of the full computation of 7 Brane instanton corrections.Comment: 13 pages, 1 figure, 2 tables. 3 references adde

Six-dimensional D_N theory and four-dimensional SO-USp quivers

We realize four-dimensional N=2 superconformal quiver gauge theories with alternating SO and USp gauge groups as compactifications of the six-dimensional D_N theory with defects. The construction can be used to analyze infinitely strongly-coupled limits and S-dualities of such gauge theories, resulting in a new class of isolated four-dimensional N=2 superconformal field theories with SO(2N)^3 flavor symmetry.Comment: 30 pages, 12 figures; v2: published versio

D-branes and orientifolds of SO(3)

We study branes and orientifolds on the group manifold of SO(3). We consider particularly the case of the equatorial branes, which are projective planes. We show that a Dirac-Born-Infeld action can be defined on them, although they are not orientable. We find that there are two orientifold projections with the same spacetime action, which differ by their action on equatorial branes.Comment: 11 pages, no figure, uses JHEP3.cls. V2 : minor correction

D=4, N=1, Type IIA Orientifolds

We study D=4, N=1, type IIA orientifold with orbifold group $Z_N$ and $Z_N \times Z_M$. We calculate one-loop vacuum amplitudes for Klein bottle, cylinder and Mobius strip and extract the tadpole divergences. We find that the tadpole cancellation conditions thus obtained are satisfied by the $Z_4$, $Z_8$, $Z'_8$, $Z'_{12}$ orientifolds while there is no solution for $Z_3$, $Z_7$, $Z_6$, $Z'_6$, $Z_{12}$. The $Z_4 \times Z_4$ type IIA orientifold is also constructed by introducing four different configurations of 6-branes. We argue about perturbative versus non-perturbative orientifold vacua under T- duality between the type IIA and the type IIB $Z_N$ orientifolds in four dimensions.Comment: 32 pages, LaTe

Adjoint Trapping: A New Phenomenon at Strong 't Hooft Coupling

Adding matter of mass m, in the fundamental representation of SU(N), to N=4 supersymmetric Yang-Mills theory, we study ``generalized quarkonium'' containing a (s)quark, an anti(s)quark, and J massless (or very light) adjoint particles. At large 't Hooft coupling $\lambda$ >> 1, the states of spin <= 1 are surprisingly light (Kruczenski et al., hep-th/0304032) and small (hep-th/0312071) with a J-independent size of order $\sqrt{\lambda}/m$. This ``trapping'' of adjoint matter in a region small compared with its Compton wavelength and compared to any confinement scale in the theory is an unfamiliar phenomenon, as it does not occur at small $\lambda$. We explore adjoint trapping further by considering the limit of large J. In particular, for J >> $\sqrt{\lambda}$ >> 1, we expect the trapping phenomenon to become unstable. Using Wilson loop methods, we show that a sharp transition, in which the generalized quarkonium states become unbound (for massless adjoints) occurs at $J \simeq 0.22 \sqrt{\lambda}$. If the adjoint scalars of N=4 are massive and the theory is confining (as, for instance, in N=1* theories) then the transition becomes a cross-over, across which the size of the states changes rapidly from ~$\sqrt{\lambda}/m$ to something of order the confinement scale ~ $\Lambda^{-1}$.Comment: Clarified transition with a better figure and improved presentation; added careful discussion of the small regime of validity of the Born-Oppenheimer computation and adjusted some remarks appropriately; also added two reference

On Large N Gauge Theories from Orientifolds

We consider four dimensional ${\cal N}=1$ supersymmetric gauge theories obtained via orientifolds of Type IIB on Abelian C^3/G orbifolds. We construct all such theories that have well defined world-sheet expansion. The number of such orientifolds is rather limited. We explain this fact in the context of recent developments in four dimensional Type IIB orientifolds. In particular, we elaborate these issues in some examples of theories where world-sheet description is inadequate due to non-perturbative (from the orientifold viewpoint) states arising from D-branes wrapping (collapsed) 2-cycles in the orbifold. We find complete agreement with the corresponding statements recently discussed in the context of Type I compactifications on toroidal orbifolds. This provides a non-trivial check for correctness of the corresponding conclusions. We also find non-trivial agreement with various field theory expectations, and point out their origin in string language. The orientifold gauge theories that do possess well defined world-sheet description have the property that in the large N limit computation of any M-point correlation function in these theories reduces to the corresponding computation in the parent ${\cal N}=4$ oriented theory.Comment: 21 pages, revtex, minor errors and misprints corrected (to appear in Phys. Rev. D

Generalized plane-fronted gravitational waves in any dimension

We study the gravitational waves in spacetimes of arbitrary dimension. They generalize the pp-waves and the Kundt waves, obtained earlier in four dimensions. Explicit solutions of the Einstein and Einstein-Maxwell equations are derived for an arbitrary cosmological constant.Comment: Revtex, 18 pages, no figure

Supergravity Microstates for BPS Black Holes and Black Rings

We demonstrate a solution generating technique, modulo some constraints, for a large class of smooth supergravity solutions with the same asymptotic charges as a five dimensional 3-charge BPS black hole or black ring, dual to a D1/D5/P system. These solutions are characterized by a harmonic function with both positive and negative poles, which induces a geometric transition whereby singular sources have disappeared and all of the net charge at infinity is sourced by fluxes through two-cycles joining the poles of the harmonic function.Comment: 25 pages, 1 figure. Fixed minor typos, references added, extra comment on gauge choic

Three Generations in Type I Compactifications

Generalizing the recent work on three-family Type I compactifications, we classify perturbative Type I vacua obtained via compactifying on the T^6/Z_2 X Z_2 X Z_3 orbifold with all possible Wilson lines. In particular, we concentrate on models with gauge groups containing the Standard Model gauge group SU(3)_c X SU(2)_w X U(1)_Y as a subgroup. All of the vacua we obtain contain D5-branes and are non-perturbative from the heterotic viewpoint. The models we discuss have three-chiral families. We study some of their phenomenological properties, and point out non-trivial problems arising in these models in the phenomenological context.Comment: 16 pages, revtex, minor misprints correcte