Scalar Quartic Effective Action on AdS5AdS_5

We review the recent results concerning the computation of cubic and quartic couplings of scalar fields in type IIB supergravity on AdS_5\times S^5 background that are dual to (extended) chiral primary operators in N=4 SYM_4. We discuss the vanishing of certain cubic and quartic couplings and non-renormalization property of corresponding correlators in the conformal field theoryComment: 6 pages, Latex, JHEP style; based on the talk by G. Arutyunov at the TMR Meeting "Quantum Aspects of Gauge Theories, Supersymmetry and Unification" held in Paris, September 199

Integrable Hamiltonian for Classical Strings on AdS_5 x S^5

We find the Hamiltonian for physical excitations of the classical bosonic string propagating in the AdS_5 x S^5 space-time. The Hamiltonian is obtained in a so-called uniform gauge which is related to the static gauge by a 2d duality transformation. The Hamiltonian is of the Nambu type and depends on two parameters: a single S^5 angular momentum J and the string tension \lambda. In the general case both parameters can be finite. The space of string states consists of short and long strings. In the sector of short strings the large J expansion with \lambda'=\lambda/J^2 fixed recovers the plane-wave Hamiltonian and higher-order corrections recently studied in the literature. In the strong coupling limit \lambda\to \infty, J fixed, the energy of short strings scales as \sqrt[4]{\lambda} while the energy of long strings scales as \sqrt{\lambda}. We further show that the gauge-fixed Hamiltonian is integrable by constructing the corresponding Lax representation. We discuss some general properties of the monodromy matrix, and verify that the asymptotic behavior of the quasi-momentum perfectly agrees with the one obtained earlier for some specific cases.Comment: 30 pages, LaTex; v2: a few comments added, misprints corrected, references adde

A note on gravity-scalar fluctuations in holographic RG flow geometries

We study five-dimensional gravity models with non-vanishing background scalar fields which are dual to non-conformal boundary field theories. We develop a procedure to decouple the graviton fluctuations from the scalar ones and apply it to the simplest case of one scalar field. The quadratic action for the decoupled scalar fluctuations has a very simple form and can be used to compute two-point functions. We perform this computation for the two examples of background RG flow recently considered by DeWolfe and Freedman and find physically reasonable results.Comment: 13 pages, latex, no figure

Stationary strings near a higher-dimensional rotating black hole

We study stationary string configurations in a space-time of a higher-dimensional rotating black hole. We demonstrate that the Nambu-Goto equations for a stationary string in the 5D Myers-Perry metric allow a separation of variables. We present these equations in the first-order form and study their properties. We prove that the only stationary string configuration which crosses the infinite red-shift surface and remains regular there is a principal Killing string. A worldsheet of such a string is generated by a principal null geodesic and a timelike at infinity Killing vector field. We obtain principal Killing string solutions in the Myers-Perry metrics with an arbitrary number of dimensions. It is shown that due to the interaction of a string with a rotating black hole there is an angular momentum transfer from the black hole to the string. We calculate the rate of this transfer in a spacetime with an arbitrary number of dimensions. This effect slows down the rotation of the black hole. We discuss possible final stationary configurations of a rotating black hole interacting with a string.Comment: 13 pages, contains additianal material at the end of Section 8, also small misprints are correcte

Perturbative and instanton corrections to the OPE of CPOs in N=4 SYM_4

We study perturbative and instanton corrections to the Operator Product Expansion of the lowest weight Chiral Primary Operators of N=4 SYM_4. We confirm the recently observed non-renormalization of various operators (notably of the double-trace operator with dimension 4 in the 20 irrep of SU(4)), that appear to be unprotected by unitarity restrictions. We demonstrate the splitting of the free-field theory stress tensor and R-symmetry current in supermultiplets acquiring different anomalous dimensions in perturbation theory and argue that certain double-trace operators also undergo a perturbative splitting into operators dual to string and two-particle gravity states respectively. The instanton contributions affect only those double-trace operators that acquire finite anomalous dimensions at strong coupling. For the leading operators of this kind, we show that the ratio of their anomalous dimensions at strong coupling to the anomalous dimensions due to instantons is the same number.Comment: Latex, 26p, typos are removed, a strong-coupling anomalous dimension of one of the double-trace operators is correcte

Rotating non-asymptotically flat black rings in charged dilaton gravity

We derive new rotating, non-asymptotically flat black ring solutions in five-dimensional Einstein-Maxwell-dilaton gravity with dilaton coupling constant $\alpha=\sqrt{8/3}$ which arises from a six-dimensional Kaluza-Klein theory. As a limiting case we also find new rotating, non-asymptotically flat five-dimensional black holes. The solutions are analyzed and the mass, angular momentum and charge are computed. A Smarr-like relation is found. It is shown that the first law of black hole thermodynamics is satisfied.Comment: 21 pages, LaTeX; v2 a reference added, typos correcte