13,893 research outputs found
Static Gauss-Bonnet Black Holes at Large
We study the static black holes in the large dimensions in the
Gauss-Bonnet gravity with a cosmological constant, coupled to the Maxewell
theory. After integrating the equation of motion with respect to the radial
direction, we obtain the effective equations at large to describe the
nonlinear dynamical deformations of the black holes. From the perturbation
analysis on the effective equations, we get the analytic expressions of the
frequencies for the quasinormal modes of charge and scalar-type perturbations.
We show that for a positive Gauss-Bonnet term, the black hole could become
unstable only if the cosmological constant is positive, otherwise the black
hole is always stable. However, for a negative Gauss-Bonnet term, we find that
the black hole could always be unstable. The instability of the black hole
depends not only on the cosmological constant and the charge, but also
significantly on the Gauss-Bonnet term. Moreover, at the onset of instability
there is a non-trivial static zero-mode perturbation, which suggests the
existence of a new non-spherically symmetric solution branch. We construct the
non-spherical symmetric static solutions of the large effective equations
explicitly.Comment: 27 pages, 34 figures. arXiv admin note: text overlap with
arXiv:1607.0471
Einstein-Gauss-Bonnet Black Strings at Large
We study the black string solutions in the Einstein-Gauss-Bonnet(EGB) theory
at large . By using the expansion in the near horizon region we derive
the effective equations that describe the dynamics of the EGB black strings.
The uniform and non-uniform black strings are obtained as the static solutions
of the effective equations. From the perturbation analysis of the effective
equations, we find that thin EGB black strings suffer from the Gregory-Laflamme
instablity and the GB term weakens the instability when the GB coefficient is
small, however, when the GB coefficient is large the GB term enhances the
instability. Furthermore, we numerically solve the effective equations to study
the non-linear instability. It turns out that the thin black strings are
unstable to developing inhomogeneities along their length, and at late times
they asymptote to the stable non-uniform black strings. The behavior is
qualitatively similar to the case in the Einstein gravity. Compared with the
black string instability in the Einstein gravity at large D, when the GB
coefficient is small the time needed to reach to final state increases, but
when the GB coefficient is large the time to reach to final state decreases.
Starting from the point of view in which the effective equations can be
interpreted as the equations for the dynamical fluid, we evaluate the transport
coefficients and find that the ratio of the shear viscosity and the entropy
density agrees with that obtained previously in the membrane paradigm after
taking the large limit.Comment: 22 pages, 8 figures, some errors corrected, references adde
Super Vust theorem and Schur-Sergeev duality for principal finite -superalgebras
In this paper, we first formulate a super version of Vust theorem associated
with a regular nilpotent element . As an application of
this theorem, we then obtain the Schur-Sergeev duality for principal finite
-superalgebras which is partially a super version of Brundan-Kleshchev's
higher level Schur-Weyl duality.Comment: 35 pages, comments are welcom
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