arXiv subjects

William S. Cunha

Publications and source records attributed to William S. Cunha.

4 recordsLinked to original sources

arXiv2026

Topological charges and confined-deconfined phase transition in holography

In recent years, many interesting works providing a topological description for black hole (BH) properties have appeared in the literature. In particular, in this framework BHs correspond to topological defects in an enlarged (off-shell) parameter space, with an associated total topological charge. In gauge/gravity duality the transition from the confined to the deconfined phase is mapped into the dominance of a BH phase in the gravity side. Here we show, using a holographic AdS/QCD model, that the introduction of an energy scale in anti-de Sitter (AdS) space results in a change in the topological class. Such a modification corresponds to the existence of confined and deconfined phases, separated by a Hawking Page transition at a finite critical temperature.

hep-th↗

arXiv2025

Hawking-Page transition in anti-de Sitter massive gravity with non-compact spatial boundary

In gauge/gravity duality, the Hawking Page (HP) process plays the important role of representing a confined/deconfined phase transition. For spaces that are asymptotically anti-de Sitter (AdS) with planar spatial boundary there is no HP transition, unless some infrared energy scale is introduced. Massive gravity theories have been applied in the context of holography in order to represent systems with momentum dissipation. In this work we study the HP transition for massive gravity in an asymptotically AdS space with $\mathbb{R}^n\times\, $S$^1 $ boundary. It is shown that the graviton mass term produces an HP transition at a finite critical temperature.

hep-th↗

arXiv2025

Holography and the internal structure of charmonium

Holographic models that consider classical vector fields in a 5-d background provide successful effective descriptions for heavy vector meson spectra. This holds both in the vacuum and in a thermal medium, like the quark gluon plasma. However, it is somehow mysterious the way that these phenomenological models work. In particular, what is the role of the fifth dimension and what is the relation between the holographic 5-d background and the physical (4-d) heavy mesons. Hadrons, in contrast to leptons, are composite particles with some internal structure, that depends on the energy at which they are observed. In this work, a static meson is represented by a heavy quark-antiquark pair with an interaction described by a Nambu Goto string living in the same 5-d background that provides field solutions leading to masses and decay constants of charmonium states. The interaction potential that shows up is linear for large distances with a string tension consistent with the effective Cornell potential. Introducing temperature $T$ in the background it is found, for the $J/ψ$ case, that there is a deconfining transition at some critical value of $T$. The results obtained indicate that the 5-d background is effectively representing the internal structure of the (static) charmonium (quasi) states.

hep-ph↗

arXiv2025

Holography and charmonium structure in a finite density plasma

It has recently been proposed that the extra dimension in holographic models for charmoniun is related to its internal structure. Representing the interaction between the quark anti-quark pair by a string inside the background used in these models, the linear term of the Cornell potential was obtained. More than that, the dissociation in the thermal medium is also described in a consistent way. Here we extend this study to the case of a plasma with finite density. The combined effects of density and temperature are analyzed from the point of view of quark anti-quark interaction and the results obtained are consistent with the ones derived previously using spectral functions.

hep-ph↗