August 3, 2022
According to the covariant open superstring description of 1/2-BPS D-branes in the AdS$_5\times$S$^5$ background, there are two kinds of purely instantonic D-branes. One is the well known D(-1)-brane or D-instanton, and another is the D1-brane spanning a two dimensional subspace inside S$^5$. We identify the actual 1/2-BPS instantonic D1-brane configurations and their supersymmetry structures. From the results, it is concluded that any spherical D1-instanton with the radius e...
May 12, 2006
We examine a non-relativistic limit of D-branes in AdS_5xS^5 and M-branes in AdS_{4/7}xS^{7/4}. First, Newton-Hooke superalgebras for the AdS branes are derived from AdSxS superalgebras as Inonu-Wigner contractions. It is shown that the directions along which the AdS-brane worldvolume extends are restricted by requiring that the isometry on the AdS-brane worldvolume and the Lorentz symmetry in the transverse space naturally extend to the super-isometry. We also derive Newton-...
November 3, 2005
We consider pure D3-brane configurations of IIB string theory which lead to supersymmetric solutions containing an AdS$_3$ factor. They can provide new examples of AdS$_3$/CFT$_2$ examples on D3-branes whose worldvolume is partially compactified. When the internal 7 dimensional space is non-compact, they can be identified as supersymmetric fluctuations of higher dimensional AdS solutions and are in general dual to 1/8-BPS operators thereof. We find that supersymmetry requires...
October 30, 2007
We study D-branes in N=1 flux compactifications to AdS_4. We derive their supersymmetry conditions and express them in terms of background generalized calibrations. Basically because AdS has a boundary, the analysis of stability is more subtle and qualitatively different from the usual case of Minkowski compactifications. For instance, stable D-branes filling AdS_4 may wrap trivial internal cycles. Our analysis gives a geometric realization of the four-dimensional field theor...
December 1, 2008
We review the spinor moving frame formulations and generalized action principle for super-p-branes, describe in detail the superembedding approach to superstring in general type IIB supergravity background and present the complete superembedding description of type IIB superstring in the AdS(5)xS*5 superspace.
November 12, 1999
AdS/CFT-correspondence establishes a relationship between supersymmetric gravity (SUGRA) on Anti-de-Sitter (AdS) space and supersymmetric Yang-Mills (SYM) theory which is conformaly invariant (CFT). The AdS space is the solution of the Einstein-Hilbert equations with a constant negative curvature. Why is this relationship important? What kind of relationship is this? How does one find it? The purpose of this text is to answer these questions. We try to present the main ideas ...
August 2, 2021
Employing the method applied to construct $AdS_5$ solutions from M5-branes recently by Bah, Bonetti, Minasian and Nardoni, we construct supersymmetric $AdS_3$ solutions from D3-branes and M5-branes wrapped on a disc with non-trivial holonomies at the boundary. In five-dimensional $U(1)^3$-gauged $\mathcal{N}=2$ supergravity, we find $\mathcal{N}=(2,2)$ and $\mathcal{N}=(4,4)$ supersymmetric $AdS_3$ solutions. We uplift the solutions to type IIB supergravity and obtain D3-bran...
January 9, 2007
We discuss confining k strings in four dimensional gauge theories using D5 branes in AdS5xS5, and D3 branes in Klebanov-Strassler and Maldacena-Nunez backgrounds. We present two results: The first that confining k string tensions in N=4 can be calculated using D5 branes in AdS5xS5 with a cut-off in the bulk AdS. Using an embedding of R2 times S4 in S5, we show that the D5 brane replicates a string of rank k in the antisymmetric representation. The second result shows that the...
April 30, 2008
In this Ph. D. Thesis we concentrate on the study of the extension of the AdS/CFT correspondence to theories with less supersymmetry. In particular, we search for the possibility of adding supersymmetric D-branes in type IIB supergravity solutions which are dual to N=1 supersymmetric gauge theories in four dimensions. In the probe approximation we perform a systematic analysis of the possible supersymmetric D-brane configurations in backgrounds dual to N=1 superconformal fiel...
October 23, 1998
Recently, Douglas and Taylor proposed to identify the Higgs vev of the Coulomb branch of the 4 dimensional N=4 super Yang-Mills theory with the positions of D3 branes in the AdS_5 x S^5 string theory. We extend this identification to more general configurations that preserve less supersymmetry. We show that a single D3 brane in AdS_5 x S^5 string theory can break the spacetime supersymmetry to 1/4 or even 1/8. Such configurations, interpretated as backgrounds of the SYM, also...