26 research outputs found
First order flow equations for nonextremal black holes in AdS (super)gravity
We consider electrically charged static nonextremal black holes in
-dimensional Einstein-Maxwell-(A)dS gravity, whose horizon is a generic
Einstein space in dimensions. It is shown that for this system the
Hamilton-Jacobi equation is exactly solvable and admits two branches of
solutions. One of them exhibits a non-simply connected domain of integration
constants and does not reduce to the well-known solution for the BPS
case. The principal functions generate two first order flows that are
analytically different, but support the same general solution. One of the two
sets of flow equations corresponds to those found by L\"u, Pope and
V\'azquez-Poritz in hep-th/0307001 and (for and ) by Miller,
Schalm and Weinberg in hep-th/0612308. This clarifies also the reason for the
very existence of first order equations for nonextremal black holes, namely,
they are just the expressions for the conjugate momenta in terms of derivatives
of the principal function in a Hamilton-Jacobi formalism. In the last part of
our paper we analyze how much of these integrability properties generalizes to
matter-coupled , gauged supergravity.Comment: 17 pages. v2: Refs. added. v3: Final version to appear in JHE
On the integrability of Einstein-Maxwell-(A)dS gravity in presence of Killing vectors
We study some symmetry and integrability properties of four-dimensional
Einstein-Maxwell gravity with nonvanishing cosmological constant in the
presence of Killing vectors. First of all, we consider stationary spacetimes,
which lead, after a timelike Kaluza-Klein reduction followed by a dualization
of the two vector fields, to a three-dimensional nonlinear sigma model coupled
to gravity, whose target space is a noncompact version of
with SU(2,1) isometry group. It is shown that the
potential for the scalars, that arises from the cosmological constant in four
dimensions, breaks three of the eight SU(2,1) symmetries, corresponding to the
generalized Ehlers and the two Harrison transformations. This leaves a
semidirect product of a one-dimensional Heisenberg group and a translation
group as residual symmetry. We show that, under the additional
assumptions that the three-dimensional manifold is conformal to a product space
, and all fields depend only on the coordinate along
, the equations of motion are integrable. This generalizes the
results of Leigh et al. in arXiv:1403.6511 to the case where also
electromagnetic fields are present. In the second part of the paper we consider
the purely gravitational spacetime admitting a second Killing vector that
commutes with the timelike one. We write down the resulting two-dimensional
action and discuss its symmetries. If the fields depend only on one of the two
coordinates, the equations of motion are again integrable, and the solution
turns out to be one constructed by Krasinski many years ago.Comment: 24 pages, uses jheppub.sty. v2: Final version to be published in CQ
Duality invariance in Fayet-Iliopoulos gauged supergravity
We propose a geometric method to study the residual symmetries in ,
Fayet-Iliopoulos (FI) gauged supergravity. It essentially
involves the stabilization of the symplectic vector of gauge couplings (FI
parameters) under the action of the U-duality symmetry of the ungauged theory.
In particular we are interested in those transformations that act non-trivially
on the solutions and produce scalar hair and dyonic black holes from a given
seed. We illustrate the procedure for finding this group in general and then
show how it works in some specific models. For the prepotential ,
we use our method to add one more parameter to the rotating Chow-Comp\`ere
solution, representing scalar hair.Comment: 31 pages, uses jheppub.sty. Final version to appear on JHE
Black string first order flow in N = 2, d = 5 abelian gauged supergravity
We derive both BPS and non-BPS first-order flow equations for magnetically
charged black strings in five-dimensional N=2 abelian gauged supergravity,
using the Hamilton-Jacobi formalism. This is first done for the coupling to
vector multiplets only and U(1) Fayet-Iliopoulos (FI) gauging, and then
generalized to the case where also hypermultiplets are present, and abelian
symmetries of the quaternionic hyperscalar target space are gauged. We then use
these results to derive the attractor equations for near-horizon geometries of
extremal black strings, and solve them explicitely for the case where the
constants appearing in the Chern-Simons term of the supergravity action satisfy
an adjoint identity. This allows to compute in generality the central charge of
the two-dimensional conformal field theory that describes the black strings in
the infrared, in terms of the magnetic charges, the CY intersection numbers and
the FI constants. Finally, we extend the r-map to gauged supergravity and use
it to relate our flow equations to those in four dimensions.Comment: 21 pages, uses jheppub.sty. v2: Minor errors corrected, refs. added.
v3: Minor error corrected in app. B, small discussion of string theory
realization added in final remark
âHigh performanceâ work practices, decentralization, and profitability: evidence from panel data -super-â
The aim of this article is to test the effects on firm profitability of the adoption of both âhigh performanceâ work practices (HPWPs) and changes in organizational design relating to the depth of the corporate hierarchy and the allocation of decision authority. For this purpose, we resort to panel estimates based on a longitudinal data set that includes information relating to 109 Italian manufacturing single-plant firms observed in the 1990s during 7 years. The econometric results show that the adoption of HPWPs leads to better performances, especially when it is associated with the delegation of decision authority downward the corporate hierarchy. Copyright 2007 , Oxford University Press.
Nonlinear symmetries of black hole entropy in gauged supergravity
Abstract Freudenthal duality in N = 2, D = 4 ungauged supergravity is generated by an anti-involutive operator that acts on the electromagnetic fluxes, and results to be a symmetry of the Bekenstein-Hawking entropy. We show that, with a suitable extension, this duality can be generalized to the abelian gauged case as well, even in presence of hypermultiplets. By defining Freudenthal duality along the scalar flow, one can prove that two configurations of charges and gaugings linked by the Freudenthal operator share the same set of values of the scalar fields at the black hole horizon. Consequently, Freudenthal duality is promoted to a nonlinear symmetry of the black hole entropy. We explicitly show this invariance for the model with prepotential F = âiX 0 X 1 and Fayet-Iliopoulos gauging
Maxillary extrafollicular adenomatoid odontogenic tumor: root resorption and involvement of the maxillary sinus and nasal cavity
Adenomatoid odontogenic tumor (AOT) is a benign, slow-growing lesion and it is considered the fourth most common odontogenic tumor. AOT affects more frequently the young subjects with a predilection for the second and third decades of life. We present here the case of a 36-year-old man affected by large extrafollicular AOT which caused roots resorption of multiple teeth. The lesion involved the entire right maxillary bone and extended into the right maxillary sinus up to the orbital floor and the nasal cavity. Intra-oral surgical excision of the AOT and functional endoscopic sinus surgery led to complete clinical healing in absence of local recurrences