arXiv subjects
Publications and source records attributed to Pablo M. Llatas.
Under the assumption of axial symmetry we introduce a map from dilatonic gravity to a string-like action. This map allows one to introduce, in a rather simple way, the equivalent of string theory T-duality in dilatonic gravity. Here we choose the duality group to be an $SO(2,1)$ group and, for a particular rotation, we recover a symmetry of dilatonic gravity discussed previously in the literature.
We show that the most general stationary electrically charged black-hole solutions of the heterotic string compactified on a (10-D)-torus (where D > 3) can be obtained by using the solution generating transformations of Sen acting on the Myers and Perry metric. The conserved charges labeling these black-hole solutions are the mass, the angular momentum in all allowed commuting planes, and 36-2D electric charges. General properties of these black-holes are also studied.
A simple field theoretical approach to Mathai-Quillen topological field theories of maps $X: M_I \to M_T$ from an internal space to a target space is presented. As an example of applications of our formalism we compute by applying our formulas the action and Q-variations of the fields of two well known topological systems: Topological Quantum Mechanics and type-A topological Sigma Model.
It is shown that two dimensional (2d) topological gravity in the conformal gauge has a larger symmetry than has been hitherto recognized; in the formulation of Labastida, Pernici and Witten it contains a twisted ``small'' N=4 superconformal symmetry. There are in fact two distinct twisted N=2 structures within this N=4, one of which is shown to be isomorphic to the algebra discussed by the Verlindes and the other corresponds, through bosonization, to $c_M\leq 1$ string theory discussed by Bershadsky et.al. As a byproduct, we find a twisted N=4 structure in $c_M\leq 1$ string theory. We also study the ``mirror'' of this twisted N=4 algebra and find that it corresponds, through another bosonization, to a constrained topological sigma model in complex dimension one.
It has been argued by Ishikawa and Kato that by making use of a specific bosonization, $c_M=1$ string theory can be regarded as a constrained topological sigma model. We generalize their construction for any $(p,q)$ minimal model coupled to two dimensional (2d) gravity and show that the energy--momentum tensor and the topological charge of a constrained topological sigma model can be mapped to the energy--momentum tensor and the BRST charge of $c_M<1$ string theory at zero cosmological constant. We systematically study the physical state spectrum of this topological sigma model and recover the spectrum in the absolute cohomology of $c_M<1$ string theory. This procedure provides us a manifestly topological representation of the continuum Liouville formulation of $c_M<1$ string theory.
In a recent work it has been shown that the bosonic strings could be embedded into a special class of $N=1$ fermionic strings. We argue that the superpartners of any physical state in the spectrum of this fermionic string is non-physical. So, there is no supersymmetry in the space of physical states and the embedding is, in this sense, ``trivial''. We here propose two different constructions as possible candidates of non-trivial embeddings of the non-critical bosonic strings into some special class of $N=1$ fermionic strings of which one is the non-critical NSR string. The BRST charge of the $N=1$ fermionic strings in both cases decompose as $Q_{N=1} = Q_B + {\tilde Q}$, where $Q_B$ is the BRST charge of the bosonic string.