We analyze the one-dimensional Dirac oscillator in a thermal bath. We found that the heat capacity is two times greater than the heat capacity of the one-dimensional harmonic oscillator for higher temperatures.Comment: 4 pages, 3 figures, to appear in Physics Letters

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The thermal properties of the three-dimensional Dirac oscillator are considered. The canonical partition function is determined, and the high-temperature limit is assessed. The degeneracy of energy levels and their physical implications on the main thermodynamic functions are analyzed, revealing that these functions assume values greater than the one-dimensional case. So that at high temperatures, the limit value of the specific heat is three times bigger.

In this paper we present two different solutions to the problem of zero mode localization of ELKO spinor. In a recent paper the present authors reopened this problem since the solution presented before did not satisfy the boundary condition at the origin. The first solution is given by the introduction of a mass term and by coupling the spinor with the brane through a delta function. The second solution is reached by a Yukawa geometrical coupling with the Ricci scalar. This two models changes consistently the the boundary condition at infinity and at the origin. For the case of Geometrical coupling we are able to show that the zero mode is localized for any smooth version of the RS model. *

The discussion of vacuum energy is currently a subject of great theoretical importance, specially concerning the cosmological constant problem in General Relativity. From Quantum Field Theory, it is stated that vacuum states subject to boundary conditions may generate tensions on these boundaries related to a measurable non-zero renormalized vacuum energy: the Casimir Effect. As such, investigating how these vacuum states and energy behave in curved backgrounds is just natural and might provide important results in the near future. In this paper we revisit a model of the Casimir Effect in weak gravitational field background, which has been proposed and further generalized in the literature. A trick originally used to simplify calculations is shown to lead to a wrong value for the energy shift, and by performing explicit mode expansion we arrive at an unexpected result: null gravitational correction even at order (M/R) 2 , in opposition to earlier results. 1

In this article we study the issue of localization of the three-form field in a Randall-Sundrum-like scenario. We simulate our membrane by kinks embedded in D=5, describing the usual case (not deformed) and new models coming from a specific deformation procedure. The gravitational background regarded includes the dilaton contribution. We show that we can only localize the zero-mode of this field for a specific range of the dilaton coupling, even in the deformed case.A study about resonances is presented. We use a numerical approach for calculations of the transmission coefficients associated to the quantum mechanical problem. This gives a clear description of the physics involved in the model. We find in this way that the appearance of resonances is strongly dependent on the coupling constant. We study the cases p = 1, 3 and 5 for α = −1.75 and α = −20. The first value of α give us one resonance peak for p = 1 and no resonances for p = 3, 5. The second value of α give us a very rich structure of resonances, with number deppending on the value of p.

Abstract. -In this work we consider the issue of localization of antisymmetric tensor fields of arbitrary rank in a D dimensional Space-time with a codimension two membrane. A string-like defect is used to simulate the membrane. The localization of massless and massive fields is found. The mass spectrum is infinitely degenerate for each mass level and this is solved by coupling the q−form to fermions.Introduction. -Higher dimensional theories are source of several ideas from the mathematical and physical point of view. Its diversity comes from the number of fields that naturally appears in their descriptions. If our universe is multidimensional then, in D = 4, all of these fields should present some signal in the accelerators. This is enough to situate the study of localization of all sort of fields as an important aspect in physics of extra dimensions. These scenarios are those in which membranes or small compactified extra dimensions plays crucial role. They are naturally embedded in the formalism of superstring Theories.As is well known, the quantum superstrings present in its spectrum a bunch of bosonic and fermionic tensorial fields: in fact, an infinite tower of them [1,2]. The understanding of the superstrings low energy limit is based on its massless excitations, and the low tension limit involves all the fields contained in its spectrum (in this case, all fields are massless) [3]. From this viewpoint, they are of great interest because they may have the status of fields describing particles other than the usual ones. As an example we can cite the space-time torsion [4] and the axion field [5,6] that have separated descriptions by the two-form. Other applications of these kind of fields are its relation with the AdS/CFT conjecture [7].The spectrum of the superstring is classified in various sectors. For example, the bosonic massless fields of the Ramond-Ramond sector in type IIA superstring is different from that in type IIB superstring. In type IIA we get a 1-form and a 3-form, while in type IIB we get a 0-form, a 2-form and a 4-form. The existence of these fields is related to the existence of stable D−branes in type II theories. These D−branes are electrically or magnetically

In this paper we discuss in detail a numerical method to study resonances in membranes generated by domain walls in Randall-Sundrum-like scenarios. It is based on similar works to understand the quantum mechanics of electrons subject to the potential barriers that exist in heterostructures in semiconductors. This method was used recently to study resonances of a three form field and lately generalized to arbitrary forms. We apply it to a lot of important models, namely those that contain the Gauge, Gravity and Spinor fields. In many cases we find a rich structure of resonances which depends on the parameters involved.