115 research outputs found
A twist on multicenter AdS solutions
The multicenter solutions of 4d supergravity contain a subset of
scaling solutions with vanishing total angular momentum. In a near limit those
solutions are asymptotically locally AdS S, but we show that a
higher moment of angular momentum contributes a subtle twist, rotating the
S with time. This provides some potential hair distinguishing the
asymptotics of these scaling solutions from the near horizon geometry of an
extremal BPS black hole.Comment: 9 pages, version accepted for publicatio
Unlocking the Axion-Dilaton in 5D Supergravity
We revisit supersymmetric solutions to five dimensional ungauged N=1
supergravity with dynamic hypermultiplets. In particular we focus on a
truncation to the axion-dilaton contained in the universal hypermultiplet. The
relevant solutions are fibrations over a four-dimensional Kahler base with a
holomorphic axion-dilaton. We focus on solutions with additional symmetries and
classify Killing vectors which preserve the additional structure imposed by
supersymmetry; in particular we extend the existing classification of solutions
with a space-like U(1) isometry to the case where the Killing vector is
rotational. We elaborate on general geometrical aspects which we illustrate in
some simple examples. We especially discuss solutions describing the
backreaction of M2-branes, which for example play a role in the black hole
deconstruction proposal for microstate geometries.Comment: 48 pages + appendices, 5 figure
Dirac actions for D-branes on backgrounds with fluxes
The understanding of the fermionic sector of the worldvolume D-brane dynamics
on a general background with fluxes is crucial in several branches of string
theory, like for example the study of nonperturbative effects or the
construction of realistic models living on D-branes. In this paper we derive a
new simple Dirac-like form for the bilinear fermionic action for any Dp-brane
in any supergravity background, which generalizes the usual Dirac action valid
in absence of fluxes. A nonzero world-volume field strength deforms the usual
Dirac operator in the action to a generalized non-canonical one. We show how
the canonical form can be re-established by a redefinition of the world-volume
geometry.Comment: 25 page
Oddity in nonrelativistic, strong gravity
We consider the presence of odd powers of the speed of light in the
covariant nonrelativistic expansion of General Relativity (GR). The term of
order in the relativistic metric is a vector potential that contributes at
leading order in this expansion and describes strong gravitational effects
outside the (post-)Newtonian regime. The nonrelativistic theory of the leading
order potentials contains the full non-linear dynamics of the stationary sector
of GR.Comment: 24 pages + appendices. Version accepted for publication by EPJC.
Subsection 4.4 on possible phenomenological applications adde
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