arXiv subjects

Tatiana Moskalets

Publications and source records attributed to Tatiana Moskalets.

2 recordsLinked to original sources

arXiv2016

Absorption cross-sections of small quasi-spherical black holes: the massless scalar case

We consider effects of non-uniformity of quasi-spherical small black hole horizons on scattering massless spineless particles in the long-wave approximation. Focusing on 4D flat and AdS neutral black hole backgrounds with conformally spherical geometry of the horizon, we observe the notable differences in compare to the scattering process on the spherically-symmetric black holes. In particular, the absorption cross-section becomes dependent on both, polar and azimuthal, spherical angles, projections of the angular momentum do not keep anymore and the angular momentum operator by itself, though remains quantised, is not quantised in integers. However, within the long-wave approximation, the main conclusion of previously obtained results on scattering on the spherically-symmetric black holes remains the same: the total absorption cross-section is proportional to the area of the black hole. The proportionality coefficient does not depend on the scalar wave frequency in the flat space black hole background, and is dependent on the admissible from the unitarity requirement frequencies in the background of AdS black hole. As a by-product of our studies we establish a quasi-spherical non-static Vaidya-type black hole solutions and outline the relation between real solutions to the elliptic Liouville equation on 2D plane and on two-dimensional sphere.

gr-qc↗

arXiv2015

Liouville mode in Gauge/Gravity Duality

We establish solutions corresponding to AdS4 static charged black holes with inhomogeneous two-dimensional horizon surfaces of constant curvature. Depending on the choice of the 2D constant curvature space, the metric potential of the internal geometry of the horizon satisfies the elliptic wave/elliptic Liouville equations. We calculate the charge diffusion and transport coefficients in the hydrodynamic limit of gauge/gravity duality and observe the exponential suppression in the diffusion coefficient and in the shear viscosity-per-entropy density ratio in the presence of an inhomogeneity on black hole horizons with planar, spherical, and hyperbolic geometry. We discuss the subtleties of the approach developed for a planar black hole with inhomogeneity distribution on the horizon surface in more detail and find, among others, a trial distribution function, which generates values of the shear viscosity-per-entropy density ratio falling within the experimentally relevant range. The solutions obtained are also extended to higher-dimensional AdS space. We observe two different DC conductivities in 4D and higher-dimensional effective strongly coupled dual media and formulate conditions under which the appropriate ratio of different conductivities is qualitatively the same as that observed in an anisotropic strongly coupled fluid. We briefly discuss ways of how the Liouville field could appear in condensed matter physics and outline prospects of further employing the gauge/gravity duality in CMP problems.

hep-th↗