26 research outputs found
String-Like BTZ on Codimension-2 Braneworlds in the Thin Brane Limit
We consider five-dimensional gravity with a Gauss-Bonnet term in the bulk and
an induced gravity term on a 2-brane of codimension-2. We show that this system
admits BTZ black holes on the 2-brane which are extended into the bulk with
regular horizons.Comment: Title changed, reference added, shortened to match the published
version in Physical Review Letter
Holographic thermalization with a chemical potential from Born-Infeld electrodynamics
The problem of holographic thermalization in the framework of Einstein
gravity coupled to Born-Infeld nonlinear electrodynamics is investigated. We
use equal time two-point correlation functions and expectation values of Wilson
loop operators in the boundary quantum field theory as probes of
thermalization, which have dual gravity descriptions in terms of geodesic
lengths and minimal area surfaces in the bulk spacetime. The full range of
values of the chemical potential per temperature ratio on the boundary is
explored. The numerical results show that the effect of the charge on the
thermalization time is similar to the one obtained with Maxwell
electrodynamics, namely the larger the charge the later thermalization occurs.
The inverse Born-Infeld parameter, on the other hand, has the opposite effect:
the more nonlinear the theory is, the sooner it thermalizes. We also study the
thermalization velocity and how the parameters affect the phase transition
point separating the thermalization process into an accelerating phase and a
decelerating phase.Comment: 29 pages, 11 figures; V2: references added, version published in JHE
Stability Analysis and Area Spectrum of 3-Dimensional Lifshitz Black Holes
In this work, we probe the stability of a three-dimensional Lifshitz
black hole by using scalar and spinorial perturbations. We found an analytical
expression for the quasinormal frequencies of the scalar probe field, which
perfectly agree with the behavior of the quasinormal modes obtained
numerically. The results for the numerical analysis of the spinorial
perturbations reinforce the conclusion of the scalar analysis, i.e., the model
is stable under scalar and spinor perturbations. As an application we found the
area spectrum of the Lifshitz black hole, which turns out to be equally spaced.Comment: 23 pages, 6 figures. References added. Version to appear in Phys.
Rev.
Information transport by sine-Gordon solitons in microtubules
We study the problem of information propagation in brain microtubules. After
considering the propagation of electromagnetic waves in a fluid of permanent
electric dipoles, the problem reduces to the sine-Gordon wave equation in one
space and one time dimensions. The problem of propagation of information is
thus set.Comment: 3 page
Shortcuts in a Nonlinear Dynamical Braneworld in Six Dimensions
We consider a dynamical brane world in a six-dimensional spacetime containing
a singularity. Using the Israel conditions we study the motion of a 4-brane
embedded in this setup. We analyse the brane behaviour when its position is
perturbed about a fixed point and solve the full nonlinear dynamics in the
several possible scenarios. We also investigate the possible gravitational
shortcuts and calculate the delay between graviton and photon signals and the
ratio of the corresponding subtended horizons.Comment: 26 pages, 9 figures. References and discussion added. Title changed
to match the version accepted in Class. and Quant. Gra
Perturbations of Gauss-Bonnet Black Strings in Codimension-2 Braneworlds
We derive the Lichnerowicz equation in the presence of the Gauss-Bonnet term.
Using the modified Lichnerowicz equation we study the metric perturbations of
Gauss-Bonnet black strings in Codimension-2 Braneworlds.Comment: 26 pages, no figures, clarifying comments and one reference added, to
be published in JHE