7 papers
Absorption on horizon-wrapped branes
S. Ansari, G. Panotopoulos, I. Sachs
We compute the absorption cross section of space-time scalars on a static D2 rane, in global coordinates, wrapped on the S^2 of an AdS_2 X S^2 X CY_3 geometry. We discuss its relev…
Quasi Normal Modes
Ivo Sachs
We review different applications of quasinormal modes to black hole physics, string theory and thermalisation in quantum field theory. In particular, we describe the the relation b…
Tachyon Dynamics and the Effective Action Approximation
N. D. Lambert, I. Sachs
Recently effective actions have been extensively used to describe tachyon condensation in string theory. While the various effective actions which have appeared in the literature h…
On Higher Derivative Terms in Tachyon Effective Actions
N. D. Lambert, I. Sachs
We reconstruct the tachyon effective action for unstable D-branes in superstring theory by examining its behaviour near exactly marginal deformations, where the ambigous higher der…
String Loop Corrections to Stable Non-BPS Branes
N. D. Lambert, I. Sachs
We calculate the string loop corrections to the tachyon potential for stable non-BPS Dp-branes on the orbifold T^4/Z_2. We find a non-trivial phase structure and we show that, afte…
Non-Abelian Born-Infeld Action and Solitons for Critical Non-BPS Branes
N. D. Lambert, I. Sachs
The non-abelian flat directions in the tachyon potential of stable non-BPS branes recently found are shown to persist to all orders in alpha' at tree level in the string coupling.…