arXiv subjects

L. Ibiapina Bevilaqua

Publications and source records attributed to L. Ibiapina Bevilaqua.

10 recordsLinked to original sources

arXiv2023

Gravitational corrections to the Einstein-Scalar-QCD model

This study employs the effective field theory approach to quantum gravity to investigate a non-Abelian gauge theory involving scalar particles coupled to gravity. The study demonstrates explicitly that the Slavnov-Taylor identities are maintained at one-loop order, which indicates that the universality of the color charge is preserved. Additionally, the graviton corrections to the two-loop gluon self-energy and its renormalization are computed.

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arXiv2022

Gravitational corrections to a non-Abelian gauge theory

This paper is part of a series of papers exploring the renormalization of field theories coupled to gravity using the effective field theory framework. In previous works we studied the universality of the electric charge and the two-loops beta function in the Einstein-QED system. Now, we use this framework to study the non-Abelian gauge theory with fermions coupled to gravity. We show that even though some of the counterterms are dependent on the gravitational coupling, the renormalized coupling constant, and therefore the beta function, do not receive any gravitational correction at one-loop order. Also, we explicitly show that, at this order, the Slavnov-Taylor identities are respected. Finally, we end the paper putting into perspective the results of the present and the past papers.

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arXiv2021

Universality of gauge coupling constant in the Einstein-QED system

In this paper we discuss the universality of the renormalization of the gauge coupling constant in the quantum electrodynamics coupled to the Einstein's gravity in the framework of effective field theory in an arbitrary gauge. We observe that the renormalization of the three-point functions with different particles receive different contributions from the gravitational sector. Despite that, the universality of the gauge coupling constants is guaranteed by the Ward identity that makes the renormalized electric charge receive no contribution from the gravitational sector at one-loop order.

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arXiv2021

Gravitational corrections to two-loop beta function in quantum electrodynamics

In this work, we use the framework of effective field theory to couple Einstein's gravity to quantum electrodynamics (QED) and determine the gravitational corrections to the two-loop beta function of the electric charge in arbitrary electrodynamics (Lorentz-like) and arbitrary (de Donder like) gravitational gauges. Our results indicate that gravitational corrections do not alter the running behavior of the electric charge; on the contrary, we observe that it gives a positive contribution to the beta function, making the electric charge grow even faster.

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arXiv2020

Renormalization group improvement of the effective potential in six dimensions

Using the renormalization group improvement technique, we study the effective potential of a model consisting of $N$ scalar fields $ϕ^i$ transforming in the fundamental representation of $O(N)$ group coupled to an additional scalar field $σ$ via cubic interactions, defined in a six-dimensional spacetime. We find that the model presents a metastable vacuum, that can be long-lived, where the particles become massive. The existence of attractive and repulsive interactions plays a crucial role in such phenomena.

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arXiv2018

Soft supersymmetry breaking in the nonlinear sigma model

In this work we discuss the dynamical generation of mass in a deformed ${\cal N}=1$ supersymmetric nonlinear sigma model in a two-dimensional ($D=1+1$) space-time. We introduce the deformation by imposing a constraint that softly breaks supersymmetry. Through the tadpole method, we compute the effective potential at leading order in $1/N$ expansion showing that the model exhibit a dynamical generation of mass to the matter fields. Supersymmetry is recovered in the limit of the deformation parameter going to zero.

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arXiv2016

Effective field theory of quantum gravity coupled to scalar electrodynamics

In this work we use the framework of effective field theory to couple Einstein's gravity to scalar electrodynamics and determine the renormalization of the model through the study of physical processes below Planck scale, a realm where quantum mechanics and general relativity are perfectly compatible. We consider the effective field theory up to dimension six operators, corresponding to processes involving one graviton exchange. Studying the renormalization group functions we see that the beta function of the electric charge is positive and possesses no contribution coming from gravitational interaction. Our result indicates that gravitational corrections do not alter the running behavior of the gauge coupling constants, even if massive particles are present.

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arXiv2014

AdS pure spinor superstring in constant backgrounds

In this paper we study the pure spinor formulation of the superstring in $AdS_5\times S^5$ around point particle solutions of the classical equations of motion. As a particular example we quantize the pure spinor string in the BMN background.

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arXiv2014

Noncommutative ${\cal N}=2$ Chern-Simons-matter model

In this work we study the three-dimensional ${\cal N}=2$ supersymmetric Chern-Simons-matter model in a noncommutative space-time. We construct the action of the noncommutative $U(N)$ non-Abelian model in terms of explicit ${\cal N}=2$ supervariables by dimensionally reducing a four-dimensional ${\cal N}=1$ supermultiplet. We also obtain the on-shell ${\cal N}=2$ supersymmetric model writing it in terms of ${\cal N}=1$ superfields. In the noncommutative Abelian case, we show that linear UV divergences are cancelled in Feynman diagrams and logarithmic divergences are absent up to one-loop order, stating that our model is free of UV/IR mixing.

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arXiv2012

On semiclassical analysis of pure spinor superstring in an AdS_5 x S^5 background

Relation between semiclassical analyses of Green-Schwarz and pure spinor formalisms in an AdS_5 x S^5 background is clarified. It is shown that the two formalisms have identical semiclassical partition functions for a simple family of classical solutions. It is also shown that, when the classical string is furthermore rigid, this in turn implies that the two formalisms predict the same one-loop corrections to spacetime energies.

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