Pedro J. Silva

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In this article we derive the full interacting effective actions for supersym-metric D-branes in arbitrary bosonic type II supergravity backgrounds. The actions are presented in terms of component fields up to second order in fermions. As one expects, the actions are built from the supercovariant derivative operator and the κ-symmetry projector. The results(More)
In this letter, using the effective action of non-BPS tachyonic D-branes, we construct the kink D1-brane super D-helix solution and its T-dual the D2-brane supertube. In the limit of zero angular momentum, both types of solutions collapse to zero radius, giving rise respectively to a degenerate string configuration corresponding to a particle travelling(More)
We find the effective action for any D-brane in a general bosonic background of supergravity. The results are explicit in component fields up to second order in the fermions and are obtained in a covariant manner. No interaction terms between fermions and the field f = b + F , characteristic of the bosonic actions, are considered. These are reserved for(More)
In this article we study giant gravitons in the framework of AdS/CFT correspondence. First, we show how to describe these configurations in the CFT side using a matrix model. In this picture, giant gravitons are realized as single excitations high above a Fermi sea, or as deep holes into it. Then, we give a prescription to define quasi-classical states and(More)
In this article we study the relation between the bubbling construction and the Mathur's microscopic solutions for the D1/D5 system. We have found that the regular near horizon D1/D5 system (after appropriated constraints are imposed) contains all the bubbling regular solutions. Then, we show that the features of this system are rather different from the(More)
In this work we consider the full interacting effective actions for fundamental strings and D-branes in arbitrary bosonic type II supergravity backgrounds. The explicit form of these actions is given in terms of component fields, up to second order in the fermions. The results take a compact form exhibiting κ-symmetry, as well as supersymmetry in a(More)
Hydrophobic cluster analysis (HCA) has long been used as a tool to detect distant homologies between protein sequences, and to classify them into different folds. However, it relies on expert human intervention, and is sensitive to subjective interpretations of pattern similarities. In this study, we describe a novel algorithm to assess the similarity of(More)