Related papers: Absorption of Scalars by Extended Objects
We examine the spectrum of a massive scalar particle interacting with the strong gravitational field of a static, spherically symmetric object which is not quite massive enough to be a black hole. As was found in the case of massless…
In Phys.Rev.D89, 104053 (2014) we studied the absorption cross section of a scalar field of mass $m$ impinging on a static black hole of mass $M$ and charge $Q$. We presented numerical results using the partial-wave method, and analytical…
This note discusses some results on the non-BPS excitations of D-branes. We show that the excitation spectrum of a bound state of D-strings changes character when the length of the wrapping circle becomes less than $\sim g^{-1}\LS$. We…
The ratio of the low-energy absorption cross section for Dirac fermion to that for minimally coupled scalar is computed when the spacetimes are various types of the higher-dimensional Reissner-Nordstr\"{o}m black holes. It is found that the…
The calculation of absorption cross sections for minimal scalars in supergravity backgrounds is an important aspect of the investigation of AdS/CFT correspondence and requires a matching of appropriate wave functions. The low energy case…
The process of adsorption on a planar repulsive, "marginal" and attractive wall of long-flexible polymer chains with excluded volume interactions is investigated. The performed scaling analysis is based on formal analogy between the polymer…
The absorption cross section is studied in the low-frequency region for a propagating scalar field under the warped AdS$_3$ black hole background in the topologically massive gravity. It can be shown that the absorption cross section is…
The semi-classical cross-sections for arbitrary partial waves of ordinary scalars to fall into certain five-dimensional black holes have a form that seems capable of explanation in terms of the effective string model. The kinematics of…
We theoretically and numerically prove that under an electromagnetic plane wave with linear polarization incident normally to cylindrical passive scatterers, a single energy diagram can integrate absorption, scattering, and extinction cross…
We present concrete solutions with accelerated expansion in string theory, requiring a small, tractable list of stress energy sources. We explain how this construction (and others in progress) evades previous no go theorems for simple…
In this paper we compute the low energy absorption cross-section for minimally coupled massles scalars and spin-$1/2$ particles, into a general spherically symmetric black hole in arbitrary dimensions. The scalars have a cross section equal…
We show that the minimally coupled massless scalar wave equation in the background of an six-dimensional extremal dyonic string (or D1-D5 brane intersection) is exactly solvable, in terms of Mathieu functions. Using this fact, we calculate…
We calculate the absorption amplitudes of a closed string state at arbitrary mass level leading to two open string states on the D-brane at high energies. As in the case of Domain-wall scattering we studied previously, this process contains…
We study scalar field perturbations on the background of non-supersymmetric black rings and of supersymmetric black rings. In the infinite-radius limit of these geometries, we are able to separate the wave equation, and to study wave…
An expression for the spacetime absorption coefficient of a scalar field in a five dimensional, near extremal black hole background is derived, which has the same form as that presented by Maldacena and Strominger, but is valid over a…
In recent years, interesting curved-space extensions of nonrelativistic (NR) string theory have been very actively pursued, where the background has a structure that is a stringy generalization of Newton-Cartan geometry. Here we show that…
We review the classical thermodynamics and the greybody factors of general (rotating) non-extreme black holes and discuss universal features of their near-horizon geometry. We motivate a microscopic interpretation of general black holes…
Obtaining black hole solutions in alternative theories of gravity can be a difficult task due to cumbersome field equations that arise in many of such theories. In order to study the strong field regime in a model-free approach, one can…
Inclusive absorption cross section of fundamental IIB string to D-string is calculated perturbatively. The leading order result agrees with estimate based on stringy Higgs mechanism via Cremmer-Scherk coupling. It is argued that the…
We investigate the transition between singular and non-singular geometries from the vantage point of perturbative field dynamics. In particular, we obtain the closed-form absorption probability for minimally-coupled massless scalars…