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F. S. Gama

Publications and source records attributed to F. S. Gama.

At least 19 recordsLinked to original sources

Higher-derivative $\mathcal{N}=1$ and $\mathcal{N}=2$ supersymmetric Maxwell-Chern-Simons theories at one loop in superspace

We define a higher-derivative generalization of Maxwell-Chern-Simons theory in $\mathcal{N}=1$ and $\mathcal{N}=2$ superspaces. In particular, the chosen higher-derivative operator is a polynomial function of the d'Alembertian of arbitrary degree, and it is introduced exclusively in the gauge sector. The main goal is to explicitly compute the one-loop quantum corrections to the superfield effective potential for these theories. This is carried out by means of background field quantization in a higher-derivative $R_ξ$ gauge. The effective potential is obtained in closed form and expressed in terms of the roots of polynomial functions.

hep-th

Nonlocal spinor superfield theory

In this work, we propose a new three-dimensional nonlocal spinor superfield model. This theory is constructed by introducing form factors in the local spinor superfield action. Then, we couple it minimally to a scalar superfield, for which we calculate the one-loop effective potential as a first constructive example of perturbative calculations in this new theory.

hep-th

Dual equivalence between the Maxwell-Chern-Simons theory and two self-dual massive models interacting with matter in $\mathcal{N}=2$, $d=3$ superspace

We investigate the $\mathcal{N} = 2$ supersymmetric generalization of the dual equivalence between the Maxwell-Chern-Simons model and two massive self-dual models. One of the self-dual models is described by a real scalar superfield, while the other is described by a chiral spinor superfield. The equivalence is analyzed in the presence of dynamical matter chiral superfields. Initially, we establish the duality by demonstrating the existence of master actions that interpolate between the models. We then show that the field equations are identical when the proper identifications are made. Finally, we confirm the dual equivalence by defining a master generating functional, which, after changing the variables, provides the generating functionals of the Maxwell-Chern-Simons model and the two massive self-dual models coupled to matter.

hep-th

Two-loop superfield effective potential for a $\mathcal{N}=2$, $d=3$ supersymmetric quantum electrodynamics with higher derivatives

In the $\mathcal{N}=2$, $d=3$ superspace, we consider a higher-derivative generalization of the supersymmetric quantum electrodynamics, where the higher-derivative operator is a polynomial function of the d'Alembertian with arbitrary degree. For this theory, we use the background field quantization in a higher-derivative $R_ξ$ gauge to explicitly calculate the superfield effective potential up to two loops in the Källerian approximation. This superfield effective potential is obtained in a closed form and in terms of elementary functions.

hep-th

Effective Potential in the 3D Massive 2-form Gauge Superfield Theory

In the $\mathcal{N}=1$, $d=3$ superspace, we propose a massive superfield theory formulated in terms of a spinor gauge superfield, whose component content includes a two-form field, and a real scalar matter superfield. For this model, we explicitly calculate the one-loop correction to the superfield effective potential. In particular, we show that the one-loop effective potential is independent the gauge-fixing parameters.

hep-th

Spontaneous Symmetry Breaking in the Nonlocal Scalar QED

We investigate the spontaneous symmetry breaking in a nonlocal version of the scalar QED. When the mass parameter $m^2$ satisfies the requirement $m^2>0$, we find that all fields, including the Nambu-Goldstone field, acquire a non-zero mass dependent on the nonlocal scales. On the other hand, when $m^2=0$, we find that the nonlocal corrections to the masses are very small and can be neglected.

hep-th

Gödel-type solutions within the f(R,Q) gravity

In this paper, we deal with the $f(R,Q)$ gravity whose action depends, besides of the scalar curvature $R$, on the higher-derivative invariant $Q=R_{μν}R^{μν}$. In order to compare this theory with the usual General Relativity (GR), we verify the consistency of Gödel-type solutions within the $f(R,Q)$ gravity and discuss the related causality issues. Explicitly, we show that in the $f(R,Q)$ gravity there are new Gödel-type completely causal solutions having no analogue in the general relativity. In particular, a remarkable Gödel-type solution corresponding to the conformally flat space and maximally symmetric for physically well-motivated matter sources, with no necessity of cosmological constant, has been considered. We demonstrate that, in contrast to GR framework, $f(R,Q)$ gravity supports new vacuum solutions with the requirement for the cosmological constant to be non-zero. Finally, causal solutions are obtained for a particular choice $f(R,Q)=R+αR^2+ βQ$.

hep-th

On the one-loop effective potential in nonlocal supersymmetric theories

Within the superfield approach, we consider the nonlocal generalization of the Wess-Zumino model and calculate the one-loop low-energy contributions to the effective action. Four different nonlocal models are considered, among which only the first model does not reduce to the standard Wess-Zumino model when we take the parameter of nonlocality of the model, $Λ$, much greater than any energy scale; in addition, this model also depends on an extra parameter, $ξ$. As to the other three models, the result looks like the renormalized effective potential for the usual Wess-Zumino model, where the normalization scale $μ$ is replaced by the $Λ$. Moreover, the fourth model displays a divergence which can be eliminated through the appropriate wave function renormalization.

hep-th

On the alternative formulation of the three-dimensional noncommutative superspace

In this paper we propose a new version for the noncommutative superspace in 3D. This version is shown to be convenient for performing quantum calculations. In the paper, we use the theory of the chiral superfield as a prototype for possible generalizations, calculating the one-loop two-point function of a chiral supefield and the one-loop low-energy effective action in this theory.

hep-th

On the generic higher-derivative N=2, d=3 gauge theory

We formulate a generic $\mathcal{N}=2$ three-dimensional superfield higher-derivative gauge theory coupled to the matter, which, in certain cases reduces to the $\mathcal{N}=2$ three-dimensional scalar super-QED, or supersymmetric Maxwell-Chern-Simons or Chern-Simons theories with matter. For this theory, we explicitly calculate the one-loop effective potential.

hep-th

On the one-loop effective potential in the higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic term

We explicitly calculate the one-loop effective potential for a higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic term. We consider the cases of minimal and nonminimal general Lagrangians. In particular, we find that in the minimal case the divergent part of the one-loop effective potential vanishes by reason of the chirality.

hep-th