887 research outputs found
Black holes in N=2 supergravity theories and harmonic functions
We present dyonic BPS static black hole solutions for general d=4, N=2
supergravity theories coupled to vector and hypermultiplets. These solutions
are generalisations of the spherically symmetric Majumdar-Papapetrou black hole
solutions of Einstein-Maxwell gravity and are completely characterised by a set
of constrained harmonic functions. In terms of the underlying special geometry,
these harmonic functions are identified with the imaginary part of the
holomorphic sections defining the special K\"ahler manifold and the metric is
expressed in terms of the symplectic invariant K\"ahler potential. The
relations of the holomorphic sections to the harmonic functions constitute the
generalised stabilisation equations for the moduli fields. In addition to
asymptotic flatness, the harmonic functions are also constrained by the
requirement that the K\"ahler connection of the underlying Hodge-K\"ahler
manifold has to vanish in order to obtain static solutions. The behaviour of
these solutions near the horizon is also explained.Comment: 20 pages, LaTeX, an important reference is adde
Special Geometry and Space-time Signature
We construct N=2 four and five-dimensional supergravity theories coupled to
vector multiplets in various space-time signatures (t,s), where t and s refer,
respectively, to the number of time and spatial dimensions. The
five-dimensional supergravity theories, t+s=5, are constructed by investigating
the integrability conditions arising from Killing spinor equations. The
five-dimensional supergravity theories can also be obtained by reducing Hull's
eleven-dimensional supergravities on a Calabi-Yau threefold. The dimensional
reductions of the five-dimensional supergravities on space and time-like
circles produce N=2 four-dimensional supergravity theories with signatures
(t-1,s) and (t,s-1) exhibiting projective special (para)-K\"ahler geometry.Comment: 13 page
Classical Entropy of N=2 Black Holes: The minimal coupling case
We discuss the entropy and the transformation properties of classical
extremal N=2 black hole solutions in supergravity theories associated with the
minimal coupling models CP(n-1,1). The entropy is given by a manifestly
invariant quantity under the embedding of the duality group SU(1,n) into
Sp(2n+2) which is a symmetry of the classical BPS mass formula.Comment: 8 pages, Late
Phantom Metrics With Killing Spinors
We study metric solutions of Einstein-anti-Maxwell theory admitting Killing
spinors. The analogue of the IWP metric which admits a space-like Killing
vector is found and is expressed in terms of a complex function satisfying the
wave equation in flat (2+1)-dimensional space-time. As examples, electric and
magnetic Kasner spaces are constructed by allowing the solution to depend only
on the time coordinate. Euclidean solutions are also presented.Comment: 13 page
Metrics Admitting Killing Spinors In Five Dimensions
BPS black hole configurations which break half of supersymmetry in the theory
of N=2, d=5 supergravity coupled to an arbitrary number of abelian vector
multiplets are discussed. A general class of solutions comprising all known BPS
rotating black hole solutions is obtained.Comment: 15 pages, Late
Euclidean Supergravity in Five Dimensions
We construct a 5D, N = 2 Euclidean theory of supergravity coupled to vector
multiplets. Upon reducing this theory over a circle we recover the action of
4D, N = 2 Euclidean supergravity coupled to vector multiplets.Comment: 13 page
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