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Leonardo Patiño

Publications and source records attributed to Leonardo Patiño.

At least 19 recordsLinked to original sources
arXiv2026

Identifying sea and valence quarks in a magnetically driven catalysis

In the present work, we study the magnetic response of a holographic plasma in a D3/D7 setup through the quasinormal spectrum of D7-brane embedding fluctuations. Extending the spectral analysis to nonzero spatial momentum, we show that the modes become increasingly quasiparticle-like as the kinetic momentum grows at fixed magnetic field, while increasing the field at fixed kinetic momentum suppresses this character. The possible existence of these competing effects in an actual quark-gluon plasma could account, on the one hand, for the partial success of quasiparticle-based effective descriptions due to the presence of a substantial population of modes stabilized by their high momentum, and, on the other, for the difficulty of isolating experimental signatures of such constituents because of the magnetic suppression that dominates at low momentum. Within the same setup, we introduce a holographic prescription to describe the contribution of valence and sea quarks to the phenomena of magnetic catalysis and its inverse, characterized herein through the induced expectation value of a scalar operator. We apply this prescription at vanishing spatial momentum to perform an initial calculation leading to results that are in agreement with those obtained from lattice QCD.

hep-th↗
arXiv2025

Emission of linearly polarized photons in a strongly coupled magnetized plasma from the gauge/gravity correspondence

We use holographic methods to show that photons emitted by a strongly coupled plasma subject to a magnetic field are linearly polarized regardless of their four-momentum, except when they propagate along the field direction. The gravitational dual is constructed using a 5D truncation of 10-dimensional type IIB supergravity, and includes a scalar field in addition to the constant magnetic one. In terms of the geometry of the collision experiment that we model, our statement is that any photon produced there has to be in its only polarization state parallel to the reaction plane.

hep-th↗
arXiv2024

Critical magnetic field in the strong regime for 3+1 holographic superconductors

In this letter, we explore different aspects of a $3+1$ strongly coupled superconductor in the presence of an intense magnetic field. In order to study this interesting and highly complicated system, we make use of the holographic correspondence. We construct a gravitational solution incorporating a fully backreacted Maxwell field while treating a charged scalar field as a perturbation propagating on this background. Our work focuses on the implications of intense magnetic fields on superconductivity in the strongly coupled regime, offering insights into the modifications that such a field induces on key aspects of the superconducting phase. Through rigorous numerical analysis of the holographic model, we uncover intriguing effects arising from the interplay between the magnetic field and the superconducting condensate.

hep-th↗
arXiv2023

Complexity of Magnetization and Magnetic Simplification

We use the complexity=volume (CV) prescription to study the effect of a magnetic field on the computational complexity for states in the gauge theories dual to two different gravitational models. In one of these theories the complexity increases with the intensity of the magnetic field, while in the other a more interesting behavior is discovered, resulting in a phenomenon that we term magnetic simplification. The relevant difference between the two theories is that the content of the second includes a scalar operator with a nonvanishing vacuum expectation value. This leads us to conclude that the direct impact of the magnetic field is to increase the complexity of a state, but it can indirectly lower it by diminishing the complexity associated to additional degrees of freedom when these do not vanish across the space. We additionally compare the results obtained working in the full ten-dimensional backgrounds and in their effective five-dimensional truncations, exhibiting that the question is still current about which surface, whether the uplift of the 5D extremal hypersurface or the extremal surface in 10D, should be used in the CV prescription.

hep-th↗
arXiv2023

Darker and brighter branes: Suppression and enhancement of photon production in a strongly coupled magnetized plasma

We extend our holographic analysis of the emission of photons by a strongly coupled plasma subject to a very intense external magnetic field. We previously showed that in a particular model, any photon produced by the plasma had to be in its only polarization state parallel to the reaction plane. In this paper we consider a construction that relaxes a formerly imposed constraint, permitting the emission of photons with either out-plane or in-plane polarization. This constitutes a completion of our former study because the fully back-reacted equations decouple for these two polarization states in such a manner that those involving the in-plane are identical to the ones we explored previously. In view of the above, part of the details concerning the calculations and of the numerical results for the differential rate of emitted photons that we present here correspond exactly to those omitted in our preceding letter. One of our main results is that the production of photons is increased by the introduction of a non-vanishing magnetic field with an intensity up to a value $B_{\vartheta}$, above which the effect is reversed and said production becomes lower than the $B=0$ case. The characteristic intensity $B_{\vartheta}$ depends on the propagation direction and tends to zero as the photon momentum becomes aligned with the magnetic field. Additionally, we also show that the magnetic field has the effect of increasing the value of the elliptic flow, providing a possible explanation for the excess measured in collision experiments. The holographic model is constructed using an effective five-dimensional action that includes a scalar field in addition to the constant magnetic field.

hep-th↗
arXiv2021

Insensitivity of the complexity rate of change to the conformal anomaly and Lloyd's bound as a possible renormalization condition

We determine the effect on the computational complexity of a conformal anomaly using the Complexity=Action prescription of the gauge/gravity correspondence. To allow the involvement of said anomaly, we extend previous studies to include arbitrary values for the anisotropic parameter and the magnetic field respectively on the Mateos-Trancanelli and the D'Hoker-Kraus holographic models. Our main result is that the rate of change of the computational complexity is independent of the conformal anomaly in both cases. In addition, this allows us to also show that, if so desired, the saturation of Lloyd's bound at infinite time can be used as a renormalization condition.

hep-th↗
arXiv2020

Melting holographic mesons by cooling a magnetized quark gluon plasma

We extend our analysis of holographic meson dissociation in the presence of an intense magnetic field. In addition to the previously known critical temperature above which the mesons melt, we found that for certain magnetic field intensities there exists a second lower critical temperature, below which stable mesons cease to exist. While we showed before that there is a range of high temperatures for which mesons can be melted by changing the magnetic field intensity, here we show that, as a consequence of the second critical point, there is also a range of low temperatures for which this phenomenom, which we term Magnetic Meson Melting (MMM), can be triggered. Additionaly, we also show that the magnetic field decreases the mass gap of the meson spectrum along with their masses. We are able to observe this by constructing a configuration that makes it possible to apply gauge/gravity methods to study fundamental degrees of freedom in a quark-gluon plasma subject to a magnetic field as intense as that expected in high energy collisions. This is achieved by the confection of a ten-dimensional background that is dual to the magnetized plasma and nonetheless permits the embedding of D7-branes in it. The main difference with previous approaches, which in consequence gives the novel results, is that the magnetic field retroacts in the geometry itself, as opposed to be confined to the world volume of the probe D7-branes.

hep-th↗
arXiv2019

Melting holographic mesons by applying a magnetic field

In the present letter we use holographic methods to show that a very intense magnetic field lowers the temperature at which the mesons melt and decreases the mass gap of the spectrum along with their masses. Consequently, there is a range of temperatures for which mesons can be melted by applying a magnetic field instead of increasing the temperature. We term this effect Magnetic Meson Melting (MMM), and we are able to observe it by constructing a configuration that makes it possible to apply gauge/gravity methods to study fundamental degrees of freedom in a quark-gluon plasma subject to a magnetic field as intense as that expected in high energy collisions. This is achieved by the confection of a ten-dimensional background that is dual to the magnetized plasma and nonetheless permits the embedding of D7-branes in it. For such a background to exist, a scalar field has to be present and hence a scalar operator of dimension 2 appears in the gauge theory. We present here the details of the background and of the embedding of flavor D7-branes in it. Since our results are obtained from the gravity dual of the gauge theory, the analysis is also interesting from the gravitational perspective.

hep-th↗
arXiv2019

Instability of a magnetized QGP sourced by a scalar operator

We use the gauge/gravity correspondence to study the thermodynamics of a magnetized quark-gluon plasma in the presence of a scalar operator of dimension $Δ=2$. We proceed by working in a five-dimensional gauged supergravity theory, where we numerically construct an asymptotically AdS$_5$ background that describes a black D3-brane in the presence of a magnetic and a scalar fields. We study the asymptotic behavior of the background and its fields close to the AdS$_5$ region to latter perform a thermodynamic analysis of the solution that includes the renormalization of the free energy associated to it. We find that because of the presence of the scalar operator, there exists a maximum intensity for the magnetic field that the plasma can hold, while for any given intensity smaller than that value, there are two states that differ in their vacuum expectation value for the scalar operator. We show that one of the two branches just mentioned is thermodynamically favored over the other.

hep-th↗
arXiv2018

Chaos, Diffusivity, and Spreading of Entanglement in Magnetic Branes, and the Strengthening of the Internal Interaction

We use holographic methods to study several chaotic properties of a super Yang-Mills theory at temperature $T$ in the presence of a background magnetic field of constant strength $\mathcal{B}$. The field theory we work on has a renormalization flow between a fixed point in the ultraviolet and another in the infrared, occurring in such a way that the energy at which the crossover takes place is a monotonically increasing function of the dimensionless ratio $\mathcal{B}/T^2$. By considering shock waves in the bulk of the dual gravitational theory, and varying $\mathcal{B}/T^2$, we study how several chaos-related properties of the system behave while the theory they live in follows the renormalization flow. In particular, we show that the entanglement and butterfly velocities generically increase in the infrared theory, violating the previously suggested upper bounds but never surpassing the speed of light. We also investigate the recent proposal relating the butterfly velocity with diffusion coefficients. We find that electric diffusion constants respect the lower bound proposed by Blake. All our results seam to consistently indicate that the global effect of the magnetic field is to strengthen the internal interaction of the system.

hep-th↗
arXiv2017

Velocity Statistics in Holographic Fluids: Magnetized Quark-Gluon Plasma and Superfluid Flow

We study the velocity statistics distribution of an external heavy particle in holographic fluids. We argue that when the dual supergravity background has a finite temperature horizon the velocity statistics goes generically as $1/v$, compatible with the jet-quenching intuition from the quark-gluon plasma. A careful analysis of the behavior of the classical string whose apparent worldsheet horizon deviates from the background horizon reveals that other regimes are possible. We numerically discuss two cases: the magnetized quark-gluon plasma and a model of superfluid flow. We explore a range of parameters in these top-down supergravity solutions including, respectively, the magnetic field and the superfluid velocity. We determine that the velocity statistics goes largely as $1/v$, however, as we leave the non-relativistic regime we observe some deviations.

hep-th↗
arXiv2016

Thermodynamics of anisotropic branes

We study the thermodynamics of flavor D7-branes embedded in an anisotropic black brane solution of type IIB supergravity. The flavor branes undergo a phase transition between a `Minkowski embedding', in which they lie outside of the horizon, and a `black hole embedding', in which they fall into the horizon. This transition depends on the black hole temperature, its degree of anisotropy, and the mass of the flavor degrees of freedom. It happens either at a critical temperature or at a critical anisotropy. A general lesson we learn from this analysis is that the anisotropy, in this particular realization, induces similar effects as the temperature. In particular, increasing the anisotropy bends the branes more and more into the horizon. Moreover, we observe that the transition becomes smoother for higher anisotropies.

hep-th↗
arXiv2015

About the tensorial nature of the Christoffel symbols, or lack thereof

From the first approach to General Relativity we learn about the Christoffel symbols, and it is easy to notice that their coordinated components do not transform as a tensor. It is then confusing to find renowned books on the subject that refer to these symbols as if they were indeed a tensor. A prominent example of such a book is "GeneralRelativity" written by Rober Wald, which has been embraced as a textbook on the matter by a large amount of prestigious institutions around the globe. The simplest alternative would be to think that the books just mentioned present a wrong description of the Christoffel symbols, but this is not the case. Understanding the mathematical foundation of why some authors treat the Christoffel symbols as a tensor provides valuable insight about the nature of the metric connection in General Relativity, and that is why in this paper we dedicate the space to the needed analysis. The discussion provided here is aimed to those that have already taken at least one class in General Relativity, hence some of the theoretical tools will be taken as known by the reader.

gr-qc↗
arXiv2013

Thermal Photons From Magnetized Bare Strange Stars

A plasma made out of strange-quark matter (SQM) and electrons, has a rather high plasma frequency (>20 MeV). Thus, a compact star made of such material all the way up to its surface, i.e., a bare strange star, would be unable to radiate away its thermal emission. We use the MIT-bag model and assume that SQM is the ground state of nuclear matter at high density. We investigate whether the presence of a magnetic field will allow propagation of radiation at frequencies below the SQM plasma frequencies. Hence, we study the presence of gyrofrequencies in a SQM plasma permeated by a strong magnetic field (B > 10^{12} G). We find that small regions in the frequency spectrum allow radiation propagation due to the presence of the magnetic fields. It is likely that narrow bands of radiation would likely be observable from magnetized bare strange stars .

astro-ph.HE↗
arXiv2012

About matter and dark-energy domination eras in R^n gravity or lack thereof

We provide further numerical evidence which shows that R^n models in f(R) metric gravity whether produces a late time acceleration in the Universe or a matter domination era (usually a transient one) but not both. Our results confirm the findings of Amendola et al. (2007), but using a different approach that avoids the mapping to scalar-tensor theories of gravity, and therefore, dispense us from any discussion or debate about frames (Einstein vs Jordan) which are endemic in this subject. This class of models has been used extensively in the literature as an alternative to the dark energy, but should be considered ruled out for being inconsistent with observations. Finally, we discuss a caveat in the analysis by Faraoni (2011), which was used to further constrain these models by using a chameleon mechanism.

gr-qc↗
arXiv2012

Topological quantization of the free massive bosonic field

We present a topological quantization of free massive bosonic fields as the first example of a classical field theory with a quantum counterpart to be studied under this formalism. First, we identify certain harmonic map as a geometric representation of this physical system. We take as a concrete example the case of free massive bosonic fields in two dimensions represented by the minimal embedding of a two dimensional surface into a pp-wave spacetime. We use this geometric representation to construct the fiber bundle corresponding to some specific field configurations and then find their topological spectra, defined in terms of the Euler invariant. We discuss the results for some particular configurations and their consequences for the energy of the system.

math-ph↗
arXiv2011

Topological discretization of bosonic strings

We apply the method of topological quantization to obtain the bosonic string topological spectrum propagating on a flat background. We define the classical configuration of the system, and construct the corresponding principal fiber bundle (pfb) that uniquely represents it. The topological spectrum is defined through the characteristic class of the pfb. We find explicit expressions for the topological spectrum for particular configurations of the bosonic strings on a Minkowski background and show that they lead to a discretization of the total energy of the system.

math-ph↗