Luiz F. C. Pereira

@workingpaper{porciúncula2024consensuseffectssocialmedia,

title = {Consensus effects of social media synthetic influence groups on scale-free networks},

author = {Giuliano G. Porciúncula and Marcone I. Sena Júnior and Luiz Felipe C. Pereira and André L. M. Vilela},

url = {https://arxiv.org/abs/2409.10830},

doi = {https://doi.org/10.48550/arXiv.2409.10830},

year  = {2024},

date = {2024-09-17},

urldate = {2024-01-01},

abstract = {Online platforms for social interactions are an essential part of modern society. With the advance of technology and the rise of algorithms and AI, content is now filtered systematically and facilitates the formation of filter bubbles. This work investigates the social consensus under limited visibility in a two-state majority-vote model on Barabási-Albert scale-free networks. In the consensus evolution, each individual assimilates the opinion of the majority of their neighbors with probability 1−q and disagrees with chance q, known as the noise parameter. We define the visibility parameter V as the probability of an individual considering the opinion of a neighbor at a given interaction. The parameter V enables us to model the limited visibility phenomenon that produces synthetic neighborhoods in online interactions. We employ Monte Carlo simulations and finite-size scaling analysis to obtain the critical noise parameter as a function of the visibility V and the growth parameter z. We find the critical exponents β/ν¯, γ/ν¯ and 1/ν¯ of and validate their unitary relation for complex networks. Our analysis shows that installing and manipulating synthetic influence groups critically undermines consensus robustness.},

keywords = {},

pubstate = {published},

tppubtype = {workingpaper}

}

@workingpaper{fonseca2024length,

title = {Length and torsion dependence of thermal conductivity in twisted graphene nanoribbons},

author = {Alexandre F. Fonseca and Luiz Felipe C. Pereira},

url = {https://arxiv.org/abs/2404.19262},

doi = {https://doi.org/10.48550/arXiv.2404.19262},

year  = {2024},

date = {2024-04-30},

urldate = {2024-01-01},

abstract = {Research on the physical properties of materials at the nanoscale is crucial for the development of breakthrough nanotechnologies. One of the key properties to consider is the ability to conduct heat, i.e., its thermal conductivity. Graphene is a remarkable nanostructure with exceptional physical properties, including one of the highest thermal conductivities (TC) ever measured. Graphene nanoribbons (GNRs) share most fundamental properties with graphene, with the added benefit of having a controllable electronic bandgap. One method to achieve such control is by twisting the GNR, which can tailor its electronic properties, as well as change their TC. Here, we revisit the dependence of the TC of twisted GNRs (TGNRs) on the number of applied turns to the GNR by calculating more precise and mathematically well defined geometric parameters related to the TGNR shape, namely, its twist and writhe. We show that the dependence of the TC on twist is not a simple function of the number of turns initially applied to a straight GNR. In fact, we show that the TC of TGNRs requires at least two parameters to be properly described. Our conclusions are supported by atomistic molecular dynamics simulations to obtain the TC of suspended TGNRs prepared under different values of initially applied turns and different sizes of their suspended part. Among possible choices of parameter pairs, we show that TC can be appropriately described by the initial number of turns and the initial twist density of the TGNRs.},

keywords = {},

pubstate = {published},

tppubtype = {workingpaper}

}

@workingpaper{fonseca2024levy,

title = {Lévy flight for electrons in graphene in the presence of regions with enhanced spin-orbit coupling},

author = {Diego B. Fonseca and Anderson L. R. Barbosa and Luiz Felipe C. Pereira},

url = {https://arxiv.org/abs/2405.10066},

doi = {https://doi.org/10.48550/arXiv.2405.10066},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

abstract = {We propose an electronic Lévy glass built from graphene nanoribbons in the presence of regions with enhanced spin-orbit coupling. Although electrons in graphene nanoribbons present a low spin-orbit coupling strength, it can be increased by a proximity effect with an appropriate substrate. We consider graphene nanoribbons with different edge types, which contain circular regions with a tunable Rashba spin-orbit coupling, whose diameter follow a power-law distribution. We find that spin-orbital clusters induce a transition from superdiffusive to diffusive charge transport, similar to what we recently reported for nanoribbons with electrostatic clusters [Phys. Rev. B. 107, 155432 (2023)]. We also investigate spin polarization in the spin-orbital Lévy glasses, and show that a finite spin polarization can be found only in the superdiffusive regime. In contrast, the spin polarization vanishes in the diffusive regime, making the electronic Lévy glass a useful device whose electronic transmission and spin polarization can be controlled by its Fermi energy. Finally, we apply a multifractal analysis to charge transmission and spin polarization, and find that the transmission time series in the superdiffusive regime are multifractal, while they tend to be monofractal in the diffusive regime. In contrast, spin polarization time series are multifractal in both regimes, characterizing a marked difference between mesoscopic fluctuations of charge transport and spin polarization in the proposed electronic Lévy glass.},

keywords = {},

pubstate = {published},

tppubtype = {workingpaper}

}

@workingpaper{tromer2023lattice,

title = {Lattice Thermal Conductivity of 2D Nanomaterials: A Simple Semi-Empirical Approach},

author = {R. M. Tromer and I. M. Felix and Luiz Felipe C. Pereira and M. G. E. Luz and L. A. Ribeiro Junior and D. S. Galvão},

url = {https://arxiv.org/abs/2307.01167},

doi = {10.48550/arXiv.2307.01167},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

abstract = {Extracting reliable information on certain physical properties of materials, like thermal behavior, such as thermal transport, which can be very computationally demanding. Aiming to overcome such difficulties in the particular case of lattice thermal conductivity (LTC) of 2D nanomaterials, we propose a simple, fast, and accurate semi-empirical approach for its calculation.The approach is based on parameterized thermochemical equations and Arrhenius-like fitting procedures, thus avoiding molecular dynamics or textitab initio protocols, which frequently demand computationally expensive simulations. As proof of concept, we obtain the LTC of some prototypical physical systems, such as graphene (and other 2D carbon allotropes), hexagonal boron nitride (hBN), silicene, germanene, binary, and ternary BNC latices and two examples of the fullerene network family. Our values are in good agreement with other theoretical and experimental estimations, nonetheless being derived in a rather straightforward way, at a fraction of the computational cost.},

keywords = {},

pubstate = {published},

tppubtype = {workingpaper}

}