22 research outputs found
Generalized Supersymmetries and Composite Structure in M-Theory
We describe generalized D=11 Poincar\'{e} and conformal supersymmetries. The
corresponding generalization of twistor and supertwistor framework is outlined
with superspinors describing BPS preons. The BPS
states as composed out of preons are introduced, and basic ideas
concerning BPS preon dynamics is presented. The lecture is based on results
obtained by J.A. de Azcarraga, I. Bandos, J.M. Izquierdo and the author.Comment: LaTeX, 7pages. Talk presented at the XVI-th Max Born Symposium
,,Supersymmetries and Quantum Symmetries `01" (21-25.09.2001, Karpacz,
Poland) and International Nankai Symposium (8-11.10.2001, Tianjin, China). To
be published in the Proceedings of Nankai Symposium, Ed. Ge Mo-Lin and J.
Park, Int. J. Mod. Phys.
Two-Component Dust in Spherically Symmetric Motion
Two components of spherically symmetric, inhomogeneous dust penetrating each
other are introduced as a generalization of the well-known Tolman-Bondi dust
solution. The field equations of this model are formulated and general
properties are discussed. inhomogeneous Special solutions with additional
symmetries - an extra Killing- or homothetic vector - and their matching to the
corresponding Tolman-Bondi solution are investigated.Comment: 16 pages, LaTeX, 5 figures, accepted for publication in Class.
Quantum Gra
Stringy Probe Particle and Force Balance
We directly derive the classical equation of motion, which governs the centre
of mass of a test string, from the string action. In a certain case, the
equation is basically same as one derived by Papapetrou, Dixon and Wald for a
test extended body. We also discuss the force balance using a stringy probe
particle for an exact spinning multi-soliton solution of
Einstein-Maxwell-Dilaton-Axion theory. It is well known that the force balance
condition yields the saturation of the Bogomol'nyi type bound in the lowest
order. In the present formulation the gyromagnetic ratio of the stringy probe
particle is automatically determined to be which is the same value as the
background soliton. As a result we can confirm the force balance via the
gravitational spin-spin interaction.Comment: 8 pages, references added, comments added, Phys. Rev. D accepte
3D heterotic string theory: new approach and extremal solutions
We develop a new formalism for the bosonic sector of low-energy heterotic
string theory toroidally compactified to three dimensions. This formalism is
based on the use of some single non-quadratic real matrix potential which
transforms linearly under the action of subgroup of the three-dimensional
charging symmetries. We formulate a new charging symmetry invariant approach
for the symmetry generation and straightforward construction of asymptotically
flat solutions. Finally, using the developed approach and the established
formal analogy between the heterotic and Einstein-Maxwell theories, we
construct a general class of the heterotic string theory extremal solutions of
the Israel-Wilson-Perjes type. This class is asymptotically flat and charging
symmetry complete; it includes the extremal solutions constructed before and
possesses the non-trivial bosonic string theory limit.Comment: 20 pages in Late
Rotating Black Holes which Saturate a Bogomol'nyi Bound
We construct and study the electrically charged, rotating black hole solution
in heterotic string theory compactified on a dimensional torus. This
black hole is characterized by its mass, angular momentum, and a
dimensional electric charge vector. One of the novel features of this solution
is that for , its extremal limit saturates the Bogomol'nyi bound. This is
in contrast with the case where the rotating black hole solution develops
a naked singularity before the Bogomol'nyi bound is reached. The extremal black
holes can be superposed, and by taking a periodic array in , one obtains
effectively four dimensional solutions without naked singularities.Comment: 13 pages, no figure
Balanced electric-magnetic dihole in Kaluza-Klein theory
We present a four-dimensional double-black-hole (or dihole) solution in
Kaluza-Klein theory, describing a superposition of an electrically charged and
a magnetically charged black hole. This system can be balanced for
appropriately chosen parameters, and the resulting space-time is completely
regular on and outside the event horizons. This solution was constructed using
the inverse-scattering method in five-dimensional vacuum gravity, in which it
describes a rotating black ring surrounding a static black hole on a Taub-NUT
background space. Various properties of this solution are studied, from both a
four- and five-dimensional perspective.Comment: 33 pages, 6 figures; v2: expanded discussion of phase space,
published versio
All the timelike supersymmetric solutions of all ungauged d=4 supergravities
We determine the form of all timelike supersymmetric solutions of all N
greater or equal than 2, d=4 ungauged supergravities, for N less or equal than
4 coupled to vector supermultiplets, using the $Usp(n+1,n+1)-symmetric
formulation of Andrianopoli, D'Auria and Ferrara and the spinor-bilinears
method, while preserving the global symmetries of the theories all the way. As
previously conjectured in the literature, the supersymmetric solutions are
always associated to a truncation to an N=2 theory that may include
hypermultiplets, although fields which are eliminated in the truncations can
have non-trivial values, as is required by the preservation of the global
symmetry of the theories. The solutions are determined by a number of
independent functions, harmonic in transverse space, which is twice the number
of vector fields of the theory (n+1). The transverse space is flat if an only
if the would-be hyperscalars of the associated N=2 truncation are trivial.Comment: v3: Some changes in the introduction. Version to be published in JHE
Stationary Black Holes: Uniqueness and Beyond
The spectrum of known black-hole solutions to the stationary Einstein
equations has been steadily increasing, sometimes in unexpected ways. In
particular, it has turned out that not all black-hole-equilibrium
configurations are characterized by their mass, angular momentum and global
charges. Moreover, the high degree of symmetry displayed by vacuum and
electro-vacuum black-hole spacetimes ceases to exist in self-gravitating
non-linear field theories. This text aims to review some developments in the
subject and to discuss them in light of the uniqueness theorem for the
Einstein-Maxwell system.Comment: Major update of the original version by Markus Heusler from 1998.
Piotr T. Chru\'sciel and Jo\~ao Lopes Costa succeeded to this review's
authorship. Significantly restructured and updated all sections; changes are
too numerous to be usefully described here. The number of references
increased from 186 to 32