64 research outputs found
Abelian Hypermultiplet Gaugings and BPS Vacua in N = 2 Supergravity
We analyze the gauging of Abelian isometries on the hypermultiplet scalar
manifolds of N = 2 supergravity in four dimensions. This involves a study of
symmetric special quaternionic-K\"ahler manifolds, building on the work of de
Wit and Van Proeyen. In particular we compute the general set of Killing
prepotentials and associated compensators for these manifolds manifolds. This
allows us to glean new insights about AdS 4 vacua which preserve the full N = 2
supersymmetry as well as BPS static black hole horizons.Comment: 22 p. (+ 14 app.); v2: published version, fix minor typos and Killing
prepotential expression
Supergravity, complex parameters and the Janis-Newman algorithm
The Demia\'nski-Janis-Newman algorithm is an original solution generating
technique. For a long time it has been limited to producing rotating solutions,
restricting to the case of a metric and real scalar fields, despite the fact
that Demia\'nski extended it to include more parameters such as a NUT charge.
Recently two independent prescriptions have been given for extending the
algorithm to gauge fields and thus electrically charged configurations. In this
paper we aim to end setting up the algorithm by providing a missing but
important piece, which is how the transformation is applied to complex scalar
fields. We illustrate our proposal through several examples taken from N=2
supergravity, including the stationary BPS solutions from Behrndt et al. and
Sen's axion-dilaton rotating black hole. Moreover we discuss solutions that
include pairs of complex parameters, such as the mass and the NUT charge, or
the electric and magnetic charges, and we explain how to perform the algorithm
in this context (with the example of Kerr-Newman-Taub-NUT and dyonic
Kerr-Newman black holes). The final formulation of the DJN algorithm can
possibly handle solutions with five of the six Pleba\'nski-Demia\'nski
parameters along with any type of bosonic fields with spin less than two
(exemplified with the SWIP solutions). This provides all the necessary tools
for applications to general matter-coupled gravity and to (gauged)
supergravity.Comment: 18 page
Quarter-BPS Black Holes in AdS-NUT from Gauged Supergravity
We study gauged supergravity with gauge group coupled to
vector multiplets and find quite general analytic solutions for quarter-BPS
black holes with mass, NUT and dyonic Maxwell charges. The solutions we find
have running scalar fields and flow in the IR region to a horizon geometry of
the form AdS.Comment: 33 pages; v2: published version, fix minor typos, add reference
Five-dimensional Janis-Newman algorithm
The Janis-Newman algorithm has been shown to be successful in finding new
sta- tionary solutions of four-dimensional gravity. Attempts for a
generalization to higher dimensions have already been found for the restricted
cases with only one angular mo- mentum. In this paper we propose an extension
of this algorithm to five dimensions with two angular momenta - using the
prescription of G. Giampieri - through two specific examples, that are the
Myers-Perry and BMPV black holes. We also discuss possible enlargements of our
prescriptions to other dimensions and maximal number of angular momenta, and
show how dimensions higher than six appear to be much more challenging to treat
within this framework. Nonetheless this general algorithm provides a
unification of the formulation in d = 3, 4, 5 of the Janis-Newman algorithm,
from which which expose several examples including the BTZ black hole.Comment: 27 page
A short note on dynamics and degrees of freedom in classical gravity
We comment on some peculiarities of matter with and without Weyl invariance
coupled to classical Einstein-Hilbert gravity for several models, in
particular, related to the counting of degrees of freedom and on the dynamics.
We find that theories where the matter action is Weyl invariant has generically
more degrees of freedom than action without the invariance. This follows from
the Weyl invariance of the metric equations of motion independently of the
invariance of the action. Then, we study another set of models with scalar
fields and show that solutions to the equations of motion are either trivial or
inconsistent. To our knowledge, these aspects of classical gravity have
not been put forward and can be interesting to be remembered when using it as a
toy model for gravity. The goal of this note is also as a pedagogical
exercise: our results follow from standard methods, but we emphasize more
direct computations.Comment: 10 pages; v2: 13 pages, add clarification
Janis-Newman algorithm: generating rotating and NUT charged black holes
In this review we present the most general form of the Janis--Newman
algorithm. This extension allows to generate configurations which contain all
bosonic fields with spin less than or equal to two (real and complex scalar
fields, gauge fields, metric field) and with five of the six parameters of the
Pleba\'nski-Demia\'nski metric (mass, electric charge, magnetic charge, NUT
charge and angular momentum). Several examples are included to illustrate the
algorithm. We also discuss the extension of the algorithm to other dimensions.Comment: 68 pages, invited review for Universe; v2: sec. 1-4, 6 and app. B
match published version, sec. 5, 7, 8 and app. A, C are specific to arxiv
versio
Deciphering and generalizing Demianski-Janis-Newman algorithm
In the case of vanishing cosmological constant, Demia\'nski has shown that
the Janis-Newman algorithm can be generalized in order to include a NUT charge
and another parameter , in addition to the angular momentum. Moreover it was
proved that only a NUT charge can be added for non-vanishing cosmological
constant. However despite the fact that the form of the coordinate
transformations was obtained, it was not explained how to perform the
complexification on the metric function, and the procedure does not follow
directly from the usual Janis-Newman rules. The goal of our paper is threefold:
explain the hidden assumptions of Demia\'nski's analysis, generalize the
computations to topological horizons (spherical and hyperbolic) and to charged
solutions, and explain how to perform the complexification of the function. In
particular we present a new solution which is an extension of the Demia\'nski
metric to hyperbolic horizons. These different results open the door to
applications in (gauged) supergravity since they allow for a systematic
application of the Demia\'nski-Janis-Newman algorithm.Comment: 14 pp. (+ 4 app.); v2: modifications to improve clarity, match
published version, available at Springer via
http://dx.doi.org/10.1007/s10714-016-2054-
Quantum Gravity from Timelike Liouville theory
A proper definition of the path integral of quantum gravity has been a
long-standing puzzle because the Weyl factor of the Euclidean metric has a
wrong-sign kinetic term. We propose a definition of two-dimensional Liouville
quantum gravity with cosmological constant using conformal bootstrap for the
timelike Liouville theory coupled to supercritical matter. We prove a no-ghost
theorem for the states in the BRST cohomology. We show that the four-point
function constructed by gluing the timelike Liouville three-point functions is
well defined and crossing symmetric (numerically) for external Liouville
energies corresponding to \textit{all} physical states in the BRST cohomology
with the choice of the Ribault-Santachiara contour for the internal energy.Comment: 42 page
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