D. Bazeia

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In this paper we consider a class of systems of two coupled real scalar fields in bidimensional spacetime, with the main motivation of studying classical or linear stability of soliton solutions. Firstly, we present the class of systems and comment on the topological profile of soliton solutions one can find from the first-order equations that solve the(More)
We investigate the population dynamics in generalized Rock-Paper-Scissors models with an arbitrary number of species N. We show, for the first time, that spiral patterns with N-arms may develop both for odd and even N , in particular in models where a bidirectional predation interaction of equal strength between all species is modified to include one(More)
We introduce a family of Rock-Paper-Scissors type models with ZN symmetry (N is the number of species) and we show that it has a very rich structure with many completely different phases. We study realizations which lead to the formation of domains, where individuals of one or more species coexist, separated by interfaces whose (average) dynamics is(More)
In this work we investigate the development of stable dynamical structures along interfaces separating domains belonging to enemy partnerships in the context of cyclic predator-prey models with an even number of species N≥8. We use both stochastic and field theory simulations in one and two spatial dimensions, as well as analytical arguments, to describe(More)
In this work we investigate the role of the symmetry of the Lagrangian on the existence of defects in systems of coupled scalar fields. We focus attention mainly on solutions where defects may nest defects. When space is non-compact we find topological BPS and non-BPS solutions that present internal structure. When space is compact the solutions are(More)
We consider a description of membranes by (2, 1)-dimensional field theory, or alternatively a description of irrotational, isentropic fluid motion by a field theory in any dimension. We show that these Galileo-invariant systems, as well as others related to them, admit a peculiar diffeomorphism symmetry, where the transformation rule for coordinates(More)
We study a variety of supersymmetric systems describing sixth-order interactions between two coupled real superfields in 2 + 1 dimensions. We search for BPS domain ribbon solutions describing minimun energy static field configurations that break one half of the supersymmetries. We then use the super-symmetric system to investigate the behavior of mesons and(More)
We search for regular tachyon kinks in an extended model, which includes the tachyon action recently proposed to describe the tachyon field. The extended model that we propose adds a new contribution to the tachyon action, which allows obtaining stable tachyon kinks of regular profile, which may appropriately lead to the singular kink found by Sen sometime(More)