arXiv subjects

Octavio C. Junqueira

Publications and source records attributed to Octavio C. Junqueira.

11 recordsLinked to original sources

arXiv2026

Phase transitions at high and low densities for a rotating QCD matter from holography

We applied the exact Andreev soft-wall holographic model to investigate phase transitions in rotating strongly interacting matter at high and low densities. Using the dual description of hadronic matter and quark-gluon plasma via thermal and charged black holes in five-dimensional AdS space with cylindrical symmetry, we find that for relativistic rotations exceeding 16\% of the speed of light, crossover transitions emerge in the low-density regime up to a critical baryon chemical potential $μ_{CPB}$. These smooth transitions, governed by the negative QCD $β$-function, describe a mixed phase of confined and deconfined matter with different angular momenta evolving into a pure plasma at very high temperatures. For $μ\geq μ_{CPB}$, first-order transitions dominate, following the critical-temperature curve of non-rotating matter. The critical point separating the low-density crossovers from high-density first-order transitions is numerically estimated as $(μ_{CPB}, T_{CP}) = (363.554, 58.507)\,\text{MeV}$.

nucl-th↗

arXiv2026

Spontaneous symmetry breaking in a non-Abelian topological gauge theory

We study the spontaneous symmetry breaking mechanism in a non-Abelian topological gauge field theory, built from the twisted $\mathcal{N} = 2$ super-Yang-Mills theory in the presence of a Fujikawa-type potential. Specifically, by employing Fujikawa's Becchi-Rouet-Stora-Tyutin method, local degrees of freedom are released from the introduction of a potential in the trivial sector of equivariant cohomology. Such a potential displays a nontrivial vacuum solution, which induces the spontaneous symmetry breaking of the gauge symmetry together with the original fermionic scalar supersymmetry of the topological action. In this case, not only massive vector bosons emerge, but also fermionic fields with massive poles. This result shows that the introduction of a topological phase in non-Abelian gauge theories could provide a mechanism of mass generation for fermions with their masses correlated to the mass of Higgs gauge bosons ($m_B$). For the SSB in the topological case, three different vacuum directions are required. Otherwise, the supersymmetry could not be broken, and mass generation for fermions will not occur. Starting with a theory with symmetry $G = SU(N)$, to obtain a gauge theory at the end of the process, we must have $N \geq 3$. We study a maximal symmetry breaking of the type $SU(3) \rightarrow U(1) \times U(1)$, and obtain their fermionic propagators with mass poles $m^2_F = m^2_B = v^2$ after SSB, being $v^2 $ the energy scale introduced by the Fujikawa-type potential.

hep-th↗

arXiv2025

Confinement/deconfinement at low temperatures and rotation in the exact soft wall model

We study the effects of rotation on the confinement/deconfinement phase transition of strongly interacting matter, at low temperatures, in the soft wall AdS/QCD model at finite density. To achieve it, we apply the Hawking-Page approach to the exact Andreev's solution of a charged rotating black hole in five-dimensional AdS space. We observe that there is a critical angular velocity ($ω_0$) of hadronic matter that depends on the baryon density, representing a strong constraint on the rotation in hadronic matter. We obtain the curve $ω_0(μ)$, which shows that the critical rotational velocity allowed for hadronic matter decreases as the chemical potential ($μ$) increases. When $μ$ approaches the most critical quark chemical potential, identified as the density of a phase transition at zero temperature for a non-rotating plasma, the rotational velocity allowed for the hadrons tends to zero. If $ω\geq ω_0 $, there is no phase transition and the QCD matter remains in the deconfined plasma phase. The QCD phase diagram is also obtained for the exact solution, and the critical temperatures are compared with the ones obtained from the Reissner-Nordström approximation. The results are interpreted as a consequence of contributions from regions relatively distant from the AdS boundary, which cause a non-negligible reduction in the deconfinement temperatures.

hep-th↗

arXiv2025

Holographic QCD phase diagram for a rotating plasma in the Hawking-Page approach

We investigate the combined effect of rotation and finite chemical potential in the confinement/deconfinement transition of strongly interacting matter. The holographic description consists of a five-dimensional geometry that contains a black hole (BH) in the deconfined (plasma) phase. The geometry is equipped with some cut-off that introduces an infrared energy scale. We consider two possibilities: the so-called hard wall and soft wall AdS/QCD models. The transition between the plasma and hadronic phases is represented holographically as a Hawking-Page transition between geometries with and without a black hole. The gravitational dual of the rotating plasma at finite density is given by a Reissner-Nordström (RN) charged anti-de Sitter (AdS) BH with non-zero angular momentum. This analysis provides the critical temperature of deconfinement as a function of the quark chemical potential and the plasma rotational velocity. For the case of very low temperatures, the dependence of the critical values of the chemical potential for the transition to occur at $ T \to 0 $ on the rotation is found.

hep-th↗

arXiv2024

Hawking-Page transition in holographic QCD at finite density

We study the confinement/deconfinement transition of QCD matter for a quark-gluon plasma at finite density using AdS/QCD duality. In order to determine the critical temperature and its dependence on the quark chemical potential, the semi-classical Hawking-Page approach is considered for a charged AdS black hole. The result obtained is consistent with the QCD phase diagram, with the critical temperature decreasing as the chemical potential increases. Using the soft wall holographic model, the value of quark density in which the phase transition occurs at zero temperature is estimated. For higher densities the QCD matter is deconfined, independent of the temperature.

hep-th↗

arXiv2023

Inhomogeneity of a rotating quark-gluon plasma from holography

Rotation affects the transition temperature between confined (hadronic) and deconfined (quark-gluon plasma) phases of the strongly interacting matter produced in non-central heavy ion collisions. A holographic description of this effect was presented recently, considering an AdS black hole with cylindrical symmetry in rotation. Here we extend this approach in order to analyse the more realistic case of strongly interacting matter that, rather than living in a cylindrical shell, spreads over a region around the rotational axis. In this case, the confined and deconfined phases may coexist. The holographic description of the plasma behaviour under rotation is shown to be consistent with the concept of local temperature for rotating frames developed by Tolman and Ehrenfest.

hep-th↗

arXiv2023

Configuration entropy of a rotating quark-gluon plasma from holography

The configuration entropy (CE) provides a measure of the stability of physical systems that are spatially localized. An increase in the CE is associated with an increase in the instability of the system. In this work we apply a recently developed holographic description of a rotating plasma, in order to investigate the behaviour of the CE when the plasma has angular momentum. Considering the holographic dual to the plasma, namely a rotating AdS black hole, the CE is computed at different rotational speeds and temperatures. The result obtained shows not only an increase with the rotational speed $ v$ but, in particular, a divergence of the CE as $v$ approaches the speed of light: $\, v \to 1 $. We discuss the results obtained showing that they are consistent with the change in the geometry of the black hole caused by the rotation and the corresponding variation of the volume of the dual plasma. We also connect the results found here with those obtained in a recent work, where it was shown that the complete dissociation of heavy mesons in a plasma is represented by a positive singularity in the CE.

hep-th↗

arXiv2022

Confinement/Deconfinement temperature for a rotating quark-gluon plasma

Non-central heavy ion collisions lead to the production of a quark gluon plasma with angular momentum. We investigate, using holographic AdS/QCD models, how does rotation of the medium affects the confinement/deconfinement transition temperature $T_c$. In holographic models, this transition is represented by a Hawking-Page process involving two asymptotically anti-de Sitter spaces. The plasma is represented here by extending the holographic approach to anti-de Sitter spaces with cylindrical symmetry. Then, the rotation of the medium is introduced through a Lorentz boost. We consider hard and soft wall AdS/QCD models. In both cases we find it out that, as the rotational velocity $v$ increases, $T_c$ decreases, following the expression $T_c(v) = T_c(0)/γ(v)$, where $γ(v)$ is the Lorentz factor.

hep-th↗

arXiv2021

Configuration entropy in the soft wall AdS/QCD model and the Wien law

The soft wall AdS/QCD holographic model provides simple estimates for the spectra of light mesons and glueballs satisfying linear Regge trajectories. It is also an interesting tool to represent the confinement/deconfinement transition of a gauge theory, that is pictured as a Hawking-Page transition from a dual geometry with no horizon to a black hole space. A very interesting tool to analyze stability of general physical systems that are localized in space is the configuration (or complexity) entropy (CE). This quantity, inspired in Shannon information entropy, is defined in terms of the energy density of the system in momentum space. The purpose of this work is to use the CE to investigate the stability of the soft wall background as a function of the temperature. A nontrivial aspect is that the geometry is an anti-de Sitter black hole, that has a singular energy density. In order to make it possible to calculate the CE, we first propose a regularized form for the black hole energy density. Then, calculating the CE, it is observed that its behavior is consistently related to the black hole instability in anti-de Sitter space. Another interesting result that emerges from this analysis is that the regularized energy density shows a behavior similar to the Wien law, satisfied by black body radiation. That means: the momentum $ k_{max} $ where the energy density is maximum, varies with the temperature $T$ obeying the relation: $ T / k_{max} = constant $ in the deconfined phase.

hep-th↗

arXiv2021

Configuration entropy and confinement/deconfinement transiton in holographic QCD

In the holographic AdS/QCD approach, the confinement/deconfinement transition is associated with the Hawking-Page transition of a thermal anti-de Sitter (AdS) space to an AdS black hole. In the case of the hard wall model, the thermal transition takes place in the planar AdS thanks to the introduction of an infrared cut-off in the geometry. The corresponding thermodynamic entropy of the $SU(N) $ gauge theory jumps from proportional to $N^0$ in the confined hadronic phase to proportional to $N^2$ in the plasma phase, corresponding to the presence of the color degrees of freedom. The Hawking-Page transition is understood by considering a semiclassical picture of a system consisting of two different geometries that are asymptotically AdS. One is the AdS black hole and the other the thermal AdS space. The relative stability between these competing geometries varies with the temperature. So, the transition is essentially a problem of stability. An interesting tool to study stability of physical systems is the configuration entropy (CE), inspired in the Shannon informational entropy. In this work we investigate the CE for the case of the AdS/QCD hard wall model at finite temperature. We propose a regularized form for the energy densities of the black hole (BH) and of the thermal AdS geometries that makes it possible to calculate their CEs as a function of the temperature. We find a relation between stability and the value of the CE for the system of asymptotically AdS geometries. Remarkably, it is found that the CE is proportional to $\log(T)$, where $T$ is the temperature. This result makes it possible to write out a simple relation between the configuration and the thermodynamic entropies.

hep-th↗

arXiv2021

Correspondence between the twisted $N = 2$ super-Yang-Mills and conformal Baulieu-Singer theories

We characterize the correspondence between the twisted $N=2$ super-Yang-Mills theory and the Baulieu-Singer topological theory quantized in the self-dual Landau gauges. While the first is based on an on-shell supersymmetry, the second is based on an off-shell Becchi-Rouet-Stora-Tyutin symmetry. Because of the equivariant cohomology, the twisted $N=2$ in the ultraviolet regime and Baulieu-Singer theories share the same observables, the Donaldson invariants for 4-manifolds. The triviality of the Gribov copies in the Baulieu-Singer theory in these gauges shows that working in the instanton moduli space on the twisted $N=2$ side is equivalent to working in the self-dual gauges on the Baulieu-Singer one. After proving the vanishing of the $β$ function in the Baulieu-Singer theory, we conclude that the twisted $N=2$ in the ultraviolet regime, in any Riemannian manifold, is correspondent to the Baulieu-Singer theory in the self-dual Landau gauges -- a conformal gauge theory defined in Euclidean flat space.

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