17 research outputs found
The complex geometry of holographic flows of quiver gauge theories
We argue that the complete Klebanov-Witten flow solution must be described by
a Calabi-Yau metric on the conifold, interpolating between the orbifold at
infinity and the cone over T^(1,1) in the interior. We show that the complete
flow solution is characterized completely by a single, simple, quasi-linear,
second order PDE, or "master equation," in two variables. We show that the
Pilch-Warner flow solution is almost Calabi-Yau: It has a complex structure, a
hermitian metric, and a holomorphic (3,0)-form that is a square root of the
volume form. It is, however, not Kahler. We discuss the relationship between
the master equation derived here for Calabi-Yau geometries and such equations
encountered elsewhere and that govern supersymmetric backgrounds with multiple,
independent fluxes.Comment: 26 pages, harvmac + amssy
Counting chiral primaries in N=1 d=4 superconformal field theories
I derive a procedure to count chiral primary states in N=1 superconformal
field theories in four dimensions. The chiral primaries are counted by putting
the N=1 field theory on S^3 X R. I also define an index that counts semi-short
multiplets of the superconformal theory. I construct N=1 supersymmetric
Lagrangians on S^3 X R for theories which are believed to flow to a conformal
fixed point in the IR. For ungauged theories I reduce the field theory to a
supersymmetric quantum mechanics, whereas for gauge theories I use chiral ring
arguments. I count chiral primaries for SU(2) SYM with three flavors and its
Seiberg dual. Those two results agree provided a new chiral ring relation
holds.Comment: 34 pages, significant revisio
D-Branes and Bundles on Elliptic Fibrations
We study the D-brane spectrum on a two-parameter Calabi-Yau model. The
analysis is based on different tools in distinct regions of the moduli space:
wrapped brane configurations on elliptic fibrations near the large radius
limit, and SCFT boundary states at the Gepner point. We develop an explicit
correspondence between these two classes of objects, suggesting that boundary
states are natural quantum generalizations of bundles. We also find interesting
D-brane dynamics in deep stringy regimes. The most striking example is,
perhaps, that nonsupersymmetric D6-D0 and D4-D2 large radius configurations
become stable BPS states at the Gepner point.Comment: 22 page
Bubbling Defect CFT's
We study the gravitational description of conformal half-BPS domain wall
operators in N=4 SYM, which are described by defect CFT's. These defect CFT's
arise in the low energy limit of a Hanany-Witten like brane setup and are
described in a probe brane approximation by a Karch-Randall brane
configuration. The gravitational backreaction takes the five-branes in
AdS_5xS^5 through a geometric transition and turns them into appropriate fluxes
which are supported on non-trivial three-spheres.Comment: 32 pages, latex, 4 figures, 2 references adde
Stability and BPS branes
We define the concept of Pi-stability, a generalization of mu-stability of
vector bundles, and argue that it characterizes N=1 supersymmetric brane
configurations and BPS states in very general string theory compactifications
with N=2 supersymmetry in four dimensions.Comment: harvmac, 18 p
The spectrum of BPS branes on a noncompact Calabi-Yau
We begin the study of the spectrum of BPS branes and its variation on lines
of marginal stability on O_P^2(-3), a Calabi-Yau ALE space asymptotic to
C^3/Z_3. We show how to get the complete spectrum near the large volume limit
and near the orbifold point, and find a striking similarity between the
descriptions of holomorphic bundles and BPS branes in these two limits. We use
these results to develop a general picture of the spectrum. We also suggest a
generalization of some of the ideas to the quintic Calabi-Yau.Comment: harvmac, 45 pp. (v2: added references