Open string attractors

We present a simple example of a supersymmetric attractor mechanism in thepurely open string context of D-branes embedded in curved space-time. Ourexample involves a class of D3-branes embedded in the 2-charge D1-D5 backgroundof type IIB whose worldvolume contains a 2-sphere. Turning on worldvolumefluxes, these branes carry induced (p,q) string charges. Supersymmetricconfigurations display a flow of the open string moduli towards an attractorsolution independent of their asymptotics. The equations governing thismechanism closely resemble the attractor flow equations for supersymmetricblack holes in closed string theory. The BPS equations take the form of agradient flow and describe worldvolume solitons interpolating between an AdS_2geometry where the two-sphere has collapsed, and an attractor solution withAdS_2 x S^2 geometry. In these limiting solutions, the preserved supersymmetryis enhanced from 4 to 8 supercharges. We also discuss the interpretation of oursolutions as intersecting brane configurations placed in the D1-D5 background,as well as the S-duality transformation to the F1-NS5 background.Comment: 37 pages, 6 figures. v2: small corrections, figure and references adde