arXiv subjects
Publications and source records attributed to Ghasem Exirifard.
The linear alpha-prime corrections and the field redefinition ambiguities are studied for half-BPS singular backgrounds representing a wrapped fundamental string. It is showed that there exist schemes in which the inclusion of all the linear alpha-prime corrections converts these singular solutions to black holes with a regular horizon for which the modified Hawking-Bekenstein entropy is in agreement with the statistical entropy.
The quadratic alpha' corrections to the two-dimensional black hole and to its T-dual are calculated. These backgrounds are used to write the covariant form of the quadratic alpha' corrections to the T-duality for general time-dependent backgrounds of dilaton and diagonal metric in the bosonic string theory.
Two and three loop alpha' corrections are calculated for Kasner and Schwarzschild metrics, and their T-duals, in the bosonic string theory. These metrics are used to obtain the two and three loop alpha' corrections to T-duality. It is noted in particular that the inclusion of alpha' corrections and the requirement of consistency with the alpha'-corrected T-duality for the Kasner and Schwarzschild metrics enables one to fix uniquely the covariant form of the T-duality rules at three loops. As a generalization of the T-dual of the Schwarzschild geometry a class of massless geometries is presented.