We introduce a method to obtain deformed defects starting from a given scalar field theory which possesses defect solutions. The procedure allows the construction of infinitely many new theories that support defect solutions, analytically expressed in terms of the defects of the original theory. The method is general, valid for both topological and non-topological defects, and we show how it extends to quantum mechanics, and how it works when the scalar field couples to fermions. We illustrate the general procedure with several examples, which support kink-like or lump-like defects. PACS numbers: 11.27.+d, 11.30.Er, 11.30.Pb Defects play important role in modern developments of several branches of physics. They may have topological or non-topological profile, and in Field Theory the topological defects usually appear in models that support spontaneous symmetry breaking, with the best known examples being kinks and domain walls, vortices and strings, and monopoles [1]. Domain walls, for example, are used to describe phenomena having rather distinct energy scales, as in high energy physics [1,2] and in condensed matter [3].The defects that we investigate in this letter are topological or kink-like defects, and nontopological or lumplike defects. They appear in models involving a single real scalar field, and are characterized by their amplitude and width, the width being related to the region in space where the defect solution appreciably deviates from vacuum states of the system. Interesting models that support kink-like defects involve polynomial potentials like the φ 4 model, periodic potentials like the sineGordon model, and even the vacuumless potential recently considered in [4,5]. We shall investigate defects by examining their solutions and the corresponding energy densities, to provide quantitative profile for both topological and nontopological defects.We introduce a general procedure to create deformed defects, starting from a known solvable model in one spatial dimension. We start with topological defects, and we show below that the proposed scheme generates, for each given model having topological solutions, infinitely many new solvable models possessing deformed topological defects. We examine stability of kink-like defects, to extend the procedure to quantum mechanics. We also investigate lump-like defects, to generalize the procedure to both topological and non-topological defects. Finally, we couple the scalar field to fermions, to show how the procedure works for the Yukawa coupling.The interest in kink-like defects is directly related to the role of symmetry restoration in cosmology [1,2] and in condensed matter [3]. Also, they are particularly important in other scenarios, where they may induce interesting effects. A significant example concerns the behavior of fermions in the background of kink-like structures [6]. The main point here is that symmetry breaking induces an effective mass term for fermions. In the background of the kink-like structure the fermionic mass varies from negative to...

We investigate a system described by two real scalar fields coupled with gravity in (4, 1) dimensions in warped spacetime involving one extra dimension. The results show that the parameter which controls the way the two scalar fields interact induces the appearence of thick brane which engenders internal structure, driving the energy density to localize inside the brane in a very specific way.

We present a method to obtain soliton solutions to relativistic system of coupled scalar fields. This is done by examining the energy associated to static field configurations. In this case we derive a set of first-order differential equations that solve the equations of motion when the energy saturates its lower bound. To illustrate the general results, we investigate some systems described by polynomial interactions in the coupled fields.Comment: RevTex4, 5 page

We investigate the presence of defects in systems described by real scalar field in (D,1) spacetime dimensions. We show that when the potential assumes specific form, there are models which support stable global defects for D arbitrary. We also show how to find first-order differential equations that solve the equations of motion, and how to solve models in D dimensions via soluble problems in D=1. We illustrate the procedure examining specific models and finding explicit solutions.PACS numbers: 11.10. Lm, 11.27.+d, 98.80.Cq The search for defect structures of topological nature is of direct interest to high energy physics, in particular to gravity in warped spacetimes involving D spatial extra dimensions. Very recently, a great deal of attention has been given to scalar fields coupled to gravity in (4, 1) dimensions [1,2,3,4,5]. Our interest here is related to Ref. [6], which deals with critical behavior of thick branes induced at high temperature, and to Refs. [7,8,9], which study the coupling of scalar and other fields to gravity in warped spacetimes involving two or more extra dimensions.These specific investigations have motivated us to study defect solutions in models involving scalar field in (D, 1) spacetime dimensions. To do this, however, we have to circumvent a theorem [10,11,12], which states that models described by a single real scalar field cannot support topological defects, unless we work in (1, 1) space-time dimensions. To evade this problem, in the present letter we consider models described by the La-, and φ is a real scalar field. The metric is (+, −, . . . , −), withis a smooth function of φ, and W φ = dW/dφ. We suppose thatφ is a critical point of V , such that V (φ) = 0. This generalization is different from the extensions one usually considers to evade the aforementined problem, which include for instance constraints in the scalar fields and/or the presence of fields with nonzero spin -see, e.g., Ref. [13], and other specific works on the subject [14,15]. Potentials of the above form appear for instance in the Gross-Pitaevski equation, which finds applications in several branches of physics -see, e.g., Ref. [16]. Other recent examples in (1, 1) dimensions include Ref. [17], which deals with the dynamics of embedded kinks, and Refs. [18], which describe scalar field in distinct backgrounds.In higher dimensions, the factor 1/r N that we introduce in Eq. (1) gives rise to an effective model, which comes from a more fundamental theory. To make this point clear, we consider the modelµν , which is a simplified Abelian version of the color dielectric model [19] in the absence of fermionssee, e.g., Ref. [20]. This model describes coupling between the real scalar field and the gauge field A µ , through the dielectric function f (φ). Here F µν = ∂ µ A ν − ∂ ν A µ is the gauge field strenght. This model shows that for spherically symmetric static configurations in the electric sector, the equation of motion for the matter field is ∇φ + (df /dφ)E 2 r = 0, where E = (E r , 0, ..., 0) is the electr...

We investigate the presence of defect structures in generalized models described by real scalar field in (1, 1) space-time dimensions. We work with two distinct generalizations, one in the form of a product of functions of the field and its derivative, and the other as a sum. We search for static solutions and study the corresponding linear stability on general grounds. We illustrate the results with several examples, where we find stable defect structures of modified profile. In particular, we show how the new defect solutions may give rise to evolutions not present in the standard scenario in higher spatial dimensions.