Viscosity bound, causality violation and instability with stringy correction and charge

We study several aspects of charged dilaton black holes with planar symmetry in (d+2)-dimensional spacetime, generalizing the four-dimensional results investigated in arXiv:0911.3586 [hep-th]. We revisit the exact solutions with both zero and finite temperature and discuss the thermodynamics of the near-extremal black holes. We calculate the AC conductivity in the zero-temperature background by solving the corresponding Schrödinger equation and find that the AC conductivity behaves like ω δ , where the exponent δ is determined by the dilaton coupling α and the spacetime dimension parameter d. Moreover, we also study the Gauss-Bonnet corrections to η/s in a five-dimensional finite-temperature background.

Section: Gauss-bonnet Corrections To η/S At Finite Temperaturementioning

confidence: 54%

Holography of charged dilaton black holes in general dimensions

Chen

Pang

2010

“…10 See [5,[130][131][132][133][134][135][136][137] for related work. 11 We would like to thank U. Gürsoy for discussion on this point.…”

Section: First-order Hydrodynamicsmentioning

confidence: 99%

Higher-derivative scalar-vector-tensor theories: black holes, Galileons, singularity cloaking and holography

Charmousis

Goutéraux

Kiritsis

2012

We consider a general Kaluza-Klein reduction of a truncated Lovelock theory. We find necessary geometric conditions for the reduction to be consistent. The resulting lower-dimensional theory is a higher derivative scalar-tensor theory, depends on a single real parameter and yields second-order field equations. Due to the presence of higherderivative terms, the theory has multiple applications in modifications of Einstein gravity (Galileon/Horndesky theory) and holography (Einstein-Maxwell-Dilaton theories). We find and analyze charged black hole solutions with planar or curved horizons, both in the 'Einstein' and 'Galileon' frame, with or without cosmological constant. Naked singularities are dressed by a geometric event horizon originating from the higher-derivative terms. The near-horizon region of the near-extremal black hole is unaffected by the presence of the higher derivatives, whether scale invariant or hyperscaling violating. In the latter case, the area law for the entanglement entropy is violated logarithmically, as expected in the presence of a Fermi surface. For negative cosmological constant and planar horizons, thermodynamics and first-order hydrodynamics are derived: the shear viscosity to entropy density ratio does not depend on temperature, as expected from the higher-dimensional scale invariance.

“…The causality gives strong constraint on the Gauss-Bonnet coupling [41][42][43][44][45][46][47][48][49] to be in the range − …”

Section: Equations Of Motion In the Bulkmentioning

confidence: 99%

Dipole coupling effect of holographic fermion in the background of charged Gauss-Bonnet AdS black hole

Kuang

Wang

2012

We investigate the holographic fermions in the charged Gauss-Bonnet AdS d black hole background with the dipole coupling between fermion and gauge field in the bulk. We show that in addition to the strength of the dipole coupling, the spacetime dimension and the higher curvature correction in the gravity background also influence the onset of the Fermi gap and the gap distance. We find that the higher curvature effect modifies the fermion spectral density and influences the value of the Fermi momentum for the appearance of the Fermi surface. There are richer physics in the boundary fermion system due to the modification in the bulk gravity.