In this paper we consider new solutions for pulsating strings. For this purpose we use the idea of the generalized ansatz for folded and circular strings in hep-th/0311004. We find the solutions to the resulting Neumann-Rosochatius integralbe system and the corrections to the energy. To do that we use the approach developed by Minahan in hep-th/0209047 and find that the corrections are quite different from those obtained in that paper and in hep-th/0310188. We conclude with comments on our solutions and the obtained corrections to the energy, expanded to the leading order in lambda. 1

In this paper we investigate the recently found γ-deformed Maldacena-Nunez background by studying the behavior of different semiclassical string configurations. This background is conjectured to be dual to dipole deformations of N = 1 SYM. We compare our results to those in the pure Maldacena-Nunez background and show that the energies of our string configurations are higher than in the undeformed background. Thinking in the lines of (hep-th/0505100) we argue that this is an evidence for better decoupling of the Kaluza-Klein modes from the pure SYM theory excitations. Moreover we are able to find a limit of the background in which the string energy is independent of γ, these strings are interpreted as corresponding to pure gauge theory effects. 1

Recently a significant progress in matching the anomalous dimensions of certain class of operators in N=4 SYM and rotating strings was made. The correspondence was established mainly by using of Bethe ansatz technique applied to the spin s Heisenberg chain model. In a recent paper Kruczenski (hep-th/0311203) suggested to solve the Heisenberg model by using of sigma model approach. In this paper we generalize the solutions obtained by Kruczenski and comment on the dual string theory. It turns out that our solution is related to a generalized ansatz for rotating strings which can be reduced to the so called Neumann-Rosochatius integrable system. We comment on the spin chain sigma model and string solutions and the possibilities for a more precise formulation of on string/gauge theory correspondence.

Some of the recent important developments in understanding string/gauge dualities are based on the idea of the highly symmetric motion of ''string solitons'' in the AdS 5 ϫS 5 geometry originally suggested by Gubser, Klebanov, and Polyakov. In this paper we study the symmetric motion of certain string configurations in the so-called Pilch-Warner geometry. The two-form field A 2 breaks down the supersymmetry to Nϭ1 but for the string configurations considered in this paper the classical values of the energy and the spin are the same as for string in AdSϫS 5 . Although trivial at the classical level, the presence of the NS-NS antisymmetric field couples the fluctuation modes that indicates changes in the quantum corrections to the energy spectrum. We compare our results with those obtained in the case of the pp-wave limit.

In this work we obtain the non-abelian T-dual geometry of the well-known Pilch-Warner supergravity solution in its infrared point. We derive the dual metric and the NS two-form by gauging the isometry group of the initial theory and integrating out the introduced auxiliary gauge fields. Then we use the Fourier-Mukai transform from algebraic geometry to find the transformation rules of the R-R fields. The dual background preserves the N = 1 supersymmetry of the original one due to the fact that the Killing spinor does not depend on the directions on which the N-AT-D is performed. Finally, we consider two different pp-wave limits of the T-dual geometry by performing Penrose limits for two light-like geodesics. Fortschritte der Physik Progress of Physics H. Dimov et al.: Non-abelian T-duality of Pilch-Warner backgroundIn the above formulas the sum over all repeating indices is implied for a, b, c = 1, 2, 3.