226 research outputs found
Symplectic and Killing Symmetries of AdS Gravity: Holographic vs Boundary Gravitons
The set of solutions to the AdS Einstein gravity with Brown-Henneaux
boundary conditions is known to be a family of metrics labeled by two arbitrary
periodic functions, respectively left and right-moving. It turns out that there
exists an appropriate presymplectic form which vanishes on-shell. This promotes
this set of metrics to a phase space in which the Brown-Henneaux asymptotic
symmetries become symplectic symmetries in the bulk of spacetime. Moreover, any
element in the phase space admits two global Killing vectors. We show that the
conserved charges associated with these Killing vectors commute with the
Virasoro symplectic symmetry algebra, extending the Virasoro symmetry algebra
with two generators. We discuss that any element in the phase space
falls into the coadjoint orbits of the Virasoro algebras and that each orbit is
labeled by the Killing charges. Upon setting the right-moving function
to zero and restricting the choice of orbits, one can take a near-horizon
decoupling limit which preserves a chiral half of the symplectic symmetries.
Here we show two distinct but equivalent ways in which the chiral Virasoro
symplectic symmetries in the near-horizon geometry can be obtained as a limit
of the bulk symplectic symmetries.Comment: 39 pages, v2: a reference added, the version to appear in JHE
Solitons in Five Dimensional Minimal Supergravity: Local Charge, Exotic Ergoregions, and Violations of the BPS Bound
We describe a number of striking features of a class of smooth solitons in
gauged and ungauged minimal supergravity in five dimensions. The solitons are
globally asymptotically flat or asymptotically AdS without any Kaluza-Klein
directions but contain a minimal sphere formed when a cycle pinches off in the
interior of the spacetime. The solutions carry a local magnetic charge and many
have rather unusual ergosurfaces. Perhaps most strikingly, many of the solitons
have more electric charge or, in the asymptotically AdS case, more electric
charge and angular momentum than is allowed by the usual BPS bound. We comment
on, but do not resolve, the new puzzle this raises for AdS/CFT.Comment: 60 pages, 12 figures, 3 table
Relaxing the Parity Conditions of Asymptotically Flat Gravity
Four-dimensional asymptotically flat spacetimes at spatial infinity are
defined from first principles without imposing parity conditions or
restrictions on the Weyl tensor. The Einstein-Hilbert action is shown to be a
correct variational principle when it is supplemented by an anomalous
counter-term which breaks asymptotic translation, supertranslation and
logarithmic translation invariance. Poincar\'e transformations as well as
supertranslations and logarithmic translations are associated with finite and
conserved charges which represent the asymptotic symmetry group. Lorentz
charges as well as logarithmic translations transform anomalously under a
change of regulator. Lorentz charges are generally non-linear functionals of
the asymptotic fields but reduce to well-known linear expressions when parity
conditions hold. We also define a covariant phase space of asymptotically flat
spacetimes with parity conditions but without restrictions on the Weyl tensor.
In this phase space, the anomaly plays classically no dynamical role.
Supertranslations are pure gauge and the asymptotic symmetry group is the
expected Poincar\'e group.Comment: Four equations corrected. Two references adde
Non-Einstein geometries in Chiral Gravity
We analyze the asymptotic solutions of Chiral Gravity (Topologically Massive
Gravity at \mu l = 1 with Brown-Henneaux boundary conditions) focusing on
non-Einstein metrics. A class of such solutions admits curvature singularities
in the interior which are reflected as singularities or infinite bulk energy of
the corresponding linear solutions. A non-linear solution is found exactly. The
back-reaction induces a repulsion of geodesics and a shielding of the
singularity by an event horizon but also introduces closed timelike curves.Comment: 11 pages, 3 figures. v2: references and comments on linear stability
(Sect.2) adde
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