arXiv subjects

Eduardo S. Nascimento

Publications and source records attributed to Eduardo S. Nascimento.

4 recordsLinked to original sources

arXiv2026

Fisher information analysis of a Langevin System with Thermal and Athermal Noise

Fisher Information (FI) has proven to be a useful tool for estimating the parameters of a system when only statistical data are available. We apply this method to a system of Langevin equations analogous to the Brownian Gyrator, in which the coupling parameter $b$ and the athermal noise strength $D$ are treated as unknown quantities. Using the FI, we discuss the estimation of the coupling parameter between the degrees of freedom and the quantity $D$ associated with the external noise effects. We find that the diagonal components of the FI exhibit nontrivial behavior, whereas the off-diagonal components display a monotonic dependence on the parameters of interest. This distinction may contribute to an accurate estimation of $b$ and $D$.

cond-mat.stat-mech↗

arXiv2024

Mean-field model for a mixture of biaxial nematogens and dipolar nanoparticles

We analyze a mean-field model for mixtures involving biaxial nematogens and dipolar nanoparticles, taking into account orientational and isotropic pair interactions between nematogens, but also orientational nematogen-nanoparticle interactions. We determine bulk equilibrium phase diagrams for a wide range of interaction strengths, identifying in each case the effect of the nanoparticles on the stability of nematic phases and on the appearance of multicritical points. Special attention is given to the limit of low concentration of nanoparticles, in which their effect on the temperatures of both the first-order uniaxial-isotropic and the continuous biaxial-uniaxial transitions is investigated in detail.

cond-mat.soft↗

arXiv2023

Brownian Fluctuations of a non-confining potential

Brownian fluctuations arise for any quantity that depends on the stochastic variables of a Brownian particle. In this study, we explore the Brownian fluctuations of a bidimensional quadratic potential that exhibits two regimes: a confining regime and a non-confining regime. We divide the total potential into two contributions and analyze the mean, variance, skewness, excess kurtosis, and their distributions for each contribution as well as for the total potential. Our analysis offers an understanding into the statistical behavior of each quantity.

cond-mat.stat-mech↗

arXiv2017

Density functional theory for dense nematics with steric interactions

The celebrated work of Onsager on hard particle systems, based on the truncated second order virial expansion, is valid at relatively low volume fractions for large aspect ratio particles. While it predicts the isotropic-nematic phase transition, it fails to provide a realistic equation of state in that the pressure remains finite for arbitrarily high densities. In this work, we derive a mean field density functional form of the Helmholtz free energy for nematics with hard core repulsion. In addition to predicting the isotropic-nematic transition, the model provides a more realistic equation of state. The energy landscape is much richer, and the orientational probability distribution function in the nematic phase possesses a unique feature: it vanishes on a nonzero measure set in orientational space.

cond-mat.soft↗