7 research outputs found
Non-extremal D-instantons
We construct the most general non-extremal deformation of the D-instanton
solution with maximal rotational symmetry. The general non-supersymmetric
solution carries electric charges of the SL(2,R) symmetry, which correspond to
each of the three conjugacy classes of SL(2,R). Our calculations naturally
generalise to arbitrary dimensions and arbitrary dilaton couplings.
We show that for specific values of the dilaton coupling parameter, the
non-extremal instanton solutions can be viewed as wormholes of non-extremal
Reissner-Nordstr\"om black holes in one higher dimension. We extend this result
by showing that for other values of the dilaton coupling parameter, the
non-extremal instanton solutions can be uplifted to non-extremal non-dilatonic
p-branes in p+1 dimensions higher.
Finally, we attempt to consider the solutions as instantons of (compactified)
type IIB superstring theory. In particular, we derive an elegant formula for
the instanton action. We conjecture that the non-extremal D-instantons can
contribute to the R^8-terms in the type IIB string effective action.Comment: 31 pages, 4 figures. v3: minor correction and reference adde
Spinning particles in the vacuum C metric
The motion of a spinning test particle given by the Mathisson-Papapetrou
equations is studied on an exterior vacuum C metric background spacetime
describing the accelerated motion of a spherically symmetric gravitational
source. We consider circular orbits of the particle around the direction of
acceleration of the source. The symmetries of this configuration lead to the
reduction of the differential equations of motion to algebraic relations. The
spin supplementary conditions as well as the coupling between the spin of the
particle and the acceleration of the source are discussed.Comment: IOP macros used, eps figures n.
Non-extremal D-instantons
We construct the most general non-extremal deformation of the D-instanton solution
with maximal rotational symmetry. The general non-supersymmetric solution carries electric
charges of the SL(2,R) symmetry, which correspond to each of the three conjugacy classes
of SL(2,R). Our calculations naturally generalise to arbitrary dimensions and arbitrary
dilaton couplings.
We show that for specific values of the dilaton coupling parameter, the non-extremal
instanton solutions can be viewed as wormholes of non-extremal Reissner-Nordstr¨om black
holes in one higher dimension. We extend this result by showing that for other values of
the dilaton coupling parameter, the non-extremal instanton solutions can be uplifted to
non-extremal non-dilatonic p-branes in p + 1 dimensions higher.
Finally, we attempt to consider the solutions as instantons of (compactified) type IIB
superstring theory. In particular, we derive an elegant formula for the instanton action. We
conjecture that the non-extremal D-instantons can contribute to the R8-terms in the type
IIB string effective action
Brane Solutions of Gravity–Dilaton–Axion Systems
We consider general properties of brane solutions of gravity-dilaton-axion systems. We focus on the case of 7-branes and instantons. In both cases we show that besides the standard solutions there are new deformed solutions whose charges take value in any of the three conjugacy classes of SL(2,R). In the case of 7-branes we find that for each conjugacy class the 7-brane solutions are 1/2 BPS. Next, we discuss the relation of the 7-branes with the DW/QFT correspondence. In particular, we show that the two (inequivalent) 7-brane solutions in the SO(2) conjugacy class have a nice interpretation as a distribution of (the so-called near horizon limit of) branes. This suggests a way to define the near-horizon limit of a 7-brane.
In the case of instantons only the solutions corresponding to the R conjugacy class are 1/2 BPS. The solutions corresponding to the other two conjugacy classess correspond to non-extremal deformations. We first discuss an alternative description of these solutions as the geodesic motion of a particle in a two-dimensional AdS2 space. Next, we discuss the instanton-soliton correspondence. In particular, we show that for two of the conjugacy classes the instanton action in D dimensions is given by the mass of the corresponding soliton which is a (non-extremal) black hole solution in D+1 dimension. We speculate on the role of the non-extremal instantons in calculating higher-derivative corrections to the string effective action and, after a generalization from a flat to a curved AdS5 background, on their role in the AdS/CFT corresopondence.
Brane Solutions of Gravity–Dilaton–Axion Systems
We consider general properties of brane solutions of gravity-dilaton-axion systems. We focus on the case of 7-branes and instantons. In both cases we show that besides the standard solutions there are new deformed solutions whose charges take value in any of the three conjugacy classes of SL(2,R). In the case of 7-branes we find that for each conjugacy class the 7-brane solutions are 1/2 BPS. Next, we discuss the relation of the 7-branes with the DW/QFT correspondence. In particular, we show that the two (inequivalent) 7-brane solutions in the SO(2) conjugacy class have a nice interpretation as a distribution of (the so-called near horizon limit of) branes. This suggests a way to define the near-horizon limit of a 7-brane. In the case of instantons only the solutions corresponding to the R conjugacy class are 1/2 BPS. The solutions corresponding to the other two conjugacy classess correspond to non-extremal deformations. We first discuss an alternative description of these solutions as the geodesic motion of a particle in a two-dimensional AdS2 space. Next, we discuss the instanton-soliton correspondence. In particular, we show that for two of the conjugacy classes the instanton action in D dimensions is given by the mass of the corresponding soliton which is a (non-extremal) black hole solution in D+1 dimension. We speculate on the role of the non-extremal instantons in calculating higher-derivative corrections to the string effective action and, after a generalization from a flat to a curved AdS5 background, on their role in the AdS/CFT corresopondence