956 research outputs found
New massive gravity, extended
We consider gravity in three dimensions with an arbitrary number of curvature
corrections. We show that such corrections are always functions of only three
independent curvature invariants. Demanding the existence of a holographic
c-theorem we show how to fix the coefficients in the action for an arbitrarily
high order, recovering the new massive gravity lagrangian at quadratic order.
We calculate the central charge and show that using Cardy's formula it
matches the entropy of black hole solutions, which we construct. We also
consider fluctuations about an AdS background, and find that it is possible to
obtain two derivative equations by imposing a single constraint, thereby
lifting the pathologic massive modes of new massive gravity. If we do not
impose this, there is a set of ghosty massive modes propagating in the bulk.
However, at these become massless and it is expected that these theories
encode the dynamics of the spin two sector of strongly coupled logarithmic
CFT's.Comment: 4 page
Attractors and first order formalism in five dimensions revisited
The attractor mechanism in five dimensional Einstein-Maxwell Chern-Simons
theory is studied. The expression of the five dimensional rotating black object
potential depending on Taub-NUT, electric and magnetic charges as well as on
all the scalar and gauge fields, is investigated. The first order formalism in
d=5 is constructed and analyzed. We derive a general expression defining the
fake superpotential which is valid for all charge configurations. An explicit
expression for the fake superpotential is constructed, for all very special
geometries, in the case of vanishing Taub-NUT charge. We carry out an analogous
construction in the very special geometries corresponding to and
models, for the most general charge configurations. The attractor flows and
horizon values of all fields are given.Comment: 33 pages, PACS numbers: 04.65.+e, 04.50.Gh, 04.70.Bw, 04.70.Dy,
keywords: five dimensional supergravity, black objects, entropy, attractor
flows, first order formalism, fake superpotential. Several typos corrected;
one reference added; section 6 (conclusions) expande
Hyper-Kaehler geometry and dualization
We demonstrate that in N=8 supersymmetric mechanics with linear and nonlinear
chiral supermultiplets one may dualize two auxiliary fields into physical ones
in such a way that the bosonic manifold will be a hyper-Kaehler one. The key
point of our construction is about different dualizations of the two auxiliary
components. One of them is turned into a physical one in the standard way
through its replacement by the total time derivative of some physical field.
The other auxiliary field is dualized through a Lagrange multiplier. We clarify
this choice of dualization by presenting the analogy with a three-dimensional
case.Comment: 9 pages, LaTeX file, PACS numbers: 11.30.Pb, 03.65.-
Superfield Formulation of Nonlinear N=4 Supermultiplets
We propose a unified superfield formulation of N=4 off-shell supermultiplets
in one spacetime dimension using the standard N=4 superspace. The main idea of
our approach is a "gluing" together of two linear supermultiplets along their
fermions. The functions defining such a gluing obey a system of equations. Each
solution of this system provides a new supermultiplet, linear or nonlinear,
modulo equivalence transformations. In such a way we reproduce all known linear
and nonlinear N=4, d=1 supermultiplets and propose some new ones. Particularly
interesting is an explicit construction of nonlinear N=4 hypermultiplets.Comment: 16 pages, no figure
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