492 research outputs found
Supersymmetric string vacua on AdS_3 x N
String backgrounds of the form AdS_3 x N that give rise to two dimensional
spacetime superconformal symmetry are constructed.Comment: harvmac, 9 pages (minor changes for submission to journal
A Gravitational Effective Action on a Finite Triangulation as a Discrete Model of Continuous Concepts
We recall how the Gauss-Bonnet theorem can be interpreted as a finite dimen-
sional index theorem. We describe the construction given in hep-th/0512293 of a
function that can be interpreted as a gravitational effective action on a
triangulation. The variation of this function under local rescalings of the
edge lengths sharing a vertex is the Euler density, and we use it to illustrate
how continuous concepts can have natural discrete analogs.Comment: 7 pages, 1 figure; Presented at the 26th Winter School GEOMETRY AND
PHYSICS at Srn
Hyperkahler Cones and Orthogonal Wolf Spaces
We construct the hyperkahler cones corresponding to the Quaternion-Kahler
orthogonal Wolf spaces SO(n+4)/(SO(n)xSO(4)) and their non-compact versions,
which appear in hypermultiplet couplings to N=2 supergravity. The geometry is
completely encoded by a single function, the hyperkahler potential, which we
compute from an SU(2) hyperkahler quotient of flat space. We derive the Killing
vectors and moment maps for the SO(n+4) isometry group on the hyperkahler cone.
For the non-compact case, the isometry group SO(n,4) contains n+2 abelian
isometries which can be used to find a dual description in terms of n tensor
multiplets and one double-tensor multiplet. Finally, using a representation of
the hyperkahler quotient via quiver diagrams, we deduce the existence of a new
eight dimensional ALE space.Comment: 19 pages, Latex, 2 figures (references added
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