2,160 research outputs found
Holographic Complexity Growth Rate in Horndeski Theory
Based on the context of complexity = action (CA) conjecture, we calculate the
holographic complexity of AdS black holes with planar and spherical topologies
in Horndeski theory. We find that the rate of change of holographic complexity
for neutral AdS black holes saturates the Lloyd's bound. For charged black
holes, we find that there exists only one horizon and thus the corresponding
holographic complexity can't be expressed as the difference of some
thermodynamical potential between two horizons as that of Reissner-Nordstrom
AdS black hole in Einstein-Maxwell theory. However, the Lloyd's bound is not
violated for charged AdS black hole in Horndeski theory.Comment: 20 pages, 6 figures, references added, typos correcte
Horndeski Gravity and the Violation of Reverse Isoperimetric Inequality
We consider Einstein-Horndeski-Maxwell gravity, together with a cosmological
constant and multiple Horndeski axions. We construct charged AdS planar black
holes in general dimensions where the Horndeski anxions span over the planar
directions. We analyse the thermodynamics and obtain the black hole volumes. We
show that the reverse isoperimetric inequality can be violated, implying that
these black holes can store information more efficiently than the Schwarzschild
black hole.Comment: Latex, 25 pages, 1 figure, references adde
Black Hole Entropy and Viscosity Bound in Horndeski Gravity
Horndeski gravities are theories of gravity coupled to a scalar field, in
which the action contains an additional non-minimal quadratic coupling of the
scalar, through its first derivative, to the Einstein tensor or the analogous
higher-derivative tensors coming from the variation of Gauss-Bonnet or Lovelock
terms. In this paper we study the thermodynamics of the static black hole
solutions in dimensions, in the simplest case of a Horndeski coupling to
the Einstein tensor. We apply the Wald formalism to calculate the entropy of
the black holes, and show that there is an additional contribution over and
above those that come from the standard Wald entropy formula. The extra
contribution can be attributed to unusual features in the behaviour of the
scalar field. We also show that a conventional regularisation to calculate the
Euclidean action leads to an expression for the entropy that disagrees with the
Wald results. This seems likely to be due to ambiguities in the subtraction
procedure. We also calculate the viscosity in the dual CFT, and show that the
viscosity/entropy ratio can violate the bound for
appropriate choices of the parameters.Comment: 30 pages, no figure, minor revision
Threshold effects as the origin of , and observed in
We investigate the decay via various rescattering
diagrams. Without introducing genuine exotic resonances, it is shown that the
, and reported by the LHCb collaboration
can be simulated by the , and threshold cusps, respectively. These cusps are enhanced by some nearby
triangle singularities. The with cannot be well simulated
by the threshold effects in our model, which implies that it may be a genuine
resonance.Comment: 7 pages, 6 figures, 2 table
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