18 research outputs found
D-branes in Supersymmetric Backgrounds
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 field theories, firstly in the AdS_5xY^{p,q} solutions and then
in their generalisation to the AdS_5xL^{a,b,c} backgrounds. Some checks of the
correspondence between D-brane configurations and chiral operators of the dual
gauge theory are performed. We also analyse the possible supersymmetric
D5-brane configurations dual to defects (of codimension one and two) in N=1 SYM
theory in the framework of the Maldacena-Nunez solution. Beyond the probe
approximation, we develop techniques in order to take into account the
backreaction undergone by the type IIB supergravity solutions (dual to N=1
superconformal field theories and their extensions to cascading theories) due
to the addition of a number of flavour branes of the same order as the number
of colour branes which generate the unflavour background. The dual
interpretation of those flavour branes is given in terms of dynamical fields
transforming in the fundamental representation of the gauge group. Several
gauge theories features are matched, like beta functions, anomalies and the
duality cascade which describes the RG flow of the cascading field theories.Comment: Ph.D. thesis. Advisor: Alfonso V. Ramallo. 211 pages, 9 figures,
LaTe
D-brane probes on L^{abc} Superconformal Field Theories
We study supersymmetric embeddings of D-brane probes of different
dimensionality in the AdS_5xL^{abc} background of type IIB string theory. In
the case of D3-branes, we recover the known three-cycles dual to the dibaryonic
operators of the gauge theory and we also find a new family of supersymmetric
embeddings. Supersymmetric configurations of D5-branes, representing fractional
branes, and of spacetime filling D7-branes (which can be used to add flavor)
are also found. Stable non supersymmetric configurations corresponding to fat
strings and domain walls are found as well.Comment: 20 pages, LaTeX;v2: minor improvements, references adde
On the M-theory description of supersymmetric gluodynamics
We study the stringy description of N=1 supersymmetric SU(N) gauge theory on
R^{1,2} X S^1. Our description is based on the known Klebanov-Strassler and
Maldacena-Nunez solutions, properly modified to account for the compact
dimension. The presence of this circle turns out to be a non trivial
modification and it leads us to consider the up-lifted eleven dimensional
solution. We discuss some of its properties. Perhaps the most interesting one
is that extra BPS M-branes are present. These generate a non-perturbative
superpotential that we explicitly compute. Our findings, besides their interest
in the gauge-string correspondence, may also have applications in the
cosmological KKLT and KKLMMT scenarios.Comment: 24 pages; typos corrected and references adde
Supersymmetric defects in the Maldacena-Nunez background
We find supersymmmetric configurations of a D5-brane probe in the
Maldacena-Nunez background which are extended along one or two of the spatial
directions of the gauge theory. These embeddings are worldvolume solitons which
behave as codimension two or one defects in the gauge theory and preserve two
of the four supersymmetries of the background.Comment: 37 pages, 2 figures, LaTeX; v2: references adde
Supersymmetric Branes on AdS_5 x Y^{p,q} and their Field Theory Duals
We systematically study supersymmetric embeddings of D-brane probes of
different dimensionality in the AdS_5xY^{p,q} background of type IIB string
theory. The main technique employed is the kappa symmetry of the probe's
worldvolume theory. In the case of D3-branes, we recover the known three-cycles
dual to the dibaryonic operators of the gauge theory and we also find a new
family of supersymmetric embeddings. The BPS fluctuations of dibaryons are
analyzed and shown to match the gauge theory results. Supersymmetric
configurations of D5-branes, representing domain walls, and of spacetime
filling D7-branes (which can be used to add flavor) are also found. We also
study the baryon vertex and some other embeddings which break supersymmetry but
are nevertheless stable.Comment: LaTeX, 2 figures, 54 pages; v2: discussions sharpened at several
points, new subsection and references adde
The supergravity dual of 3d supersymmetric gauge theories with unquenched flavors
We obtain the supergravity dual of N=1 supersymmetric gauge theory in 2+1
dimensions with a large number of unquenched massless flavors. The geometries
found are obtained by solving the equations of motion of supergravity coupled
to a suitable continuous distribution of flavor branes. The background obtained
preserves two supersymmetries. We find that when N_c\ge 2N_f the behavior of
the solutions is compatible with having an asymptotically free dual gauge
theory with dynamical quarks. On the contrary, when N_c<2N_f the theory
develops a Landau pole in the UV. We also find a new family of (unflavored)
backgrounds generated by D5-branes that wrap a three-cycle of a cone with G_2
holonomy.Comment: 56 pages, 11 figures; v2: references adde