Nuno Crokidakis

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Pictures: Talk at a SocioPhysics conference in the Ecole Polytechnique (Paris, 2011) - View of the campus of UFF to the Guanabara Bay, showing the “Pão de Açúcar” and the “Corcovado”

“The true logic of the world is in the calculus of probabilities.” - James Clerk Maxwell

Welcome to my homepage! I am PhD in Physics and Associate Professor of the Physics Institute of the Universidade Federal Fluminense, at Niterói - Rio de Janeiro, Brazil. My research is focused on computer simulations of complex systems. In other words, my interest is the study of systems constituted by a large number of units that interact under certain rules. As examples, we can cite the neurons in the brain, spins in a magnetic system, agents in the stock market, proteins in a metabolic network, individuals with distinct opinions in a group or population, cars in roads, and many others. It is an interdisciplinary research field whose aim is to explain the behavior of macroscopic systems by studying the statistical properties of their microscopic constituents. In analogy with the standard Statistical Physics, in those systems it is common the occurrence of long-range correlations, power laws and order-disorder phase transitions.

The research topic I am more interested in the last years is the modeling of Social Phenomena. The relation of these systems with the traditional Physics is not restricted to the occurrence of Critical Phenomena. Just as Statistical Physics models explain how a collection of atoms can exhibit the correlated behavior necessary to produce a ferromagnet, Social Science models wish to explain interdependent behaviors. The basic idea in Statistical Physics - that the behavior of one atom is influenced by the behavior of other atoms - is thus similar to the social science claim that one individual’s decisions depend upon the decisions of others; therein lies the possibility of a common mathematical and/or computational structure. An interesting discussion about this relation can be found in the paper of Steven Durlauf, How can statistical mechanics contribute to social science?

In the following, I present my research areas and my list of publications (citations can be found at Google Scholar). The preprints may be easily uploaded at Arxiv.

My CV in portuguese may be found here.

Education

Research

  • Statistical Physics of Socioeconomic Problems: agent-based models, opinion dynamics, language dynamics, rumor spreading, dynamics of taxpayers, stochastic processes
  • Statistical Physics of Biological Systems: population dynamics, epidemic spreading, branching processes, evolutionary dynamics
  • Nonequilibrium Phase Transitions: percolation, contact processes, magnetism, models with absorbing states, complex networks
  • Disordered Magnetic Systems: spin glasses, models with random fields and/or competing interactions, critical phenomena, Monte Carlo simulation
  • Transportation Networks: optimization, human mobility

Publications

Work in Progress

Book

livronuno.jpg My master thesis was published in 2010 in a book format by the Lambert Academic Publishing, Germany. The title is Phase Transitions in Disordered Systems under Random Magnetic Fields. In this book, I discuss the effects of different kinds of disorder in the phase diagrams of Ising-type models, using the mean-field theory. Those kind of models are of great theoretical interest, because they exhibit a rich critical phenomenon. In addition, there are experimental realizations of spin models in the presence of random magnetic fields: antiferromagnets like Fe_{x}Mg_{1-x}Cl_{2} and Fe_{x}Zn_{1-x}F_{2} submitted to an uniform magnetic field.

Numerical Codes (C language)

Colaborations

  • Celia Anteneodo - Pontifical Catholic University of Rio de Janeiro - Rio de Janeiro, Brazil
  • Edgardo Brigatti - Federal University of Rio de Janeiro - Rio de Janeiro, Brazil

Teaching Experience

  • Experimental Physics - 2007
  • Newtonian Mechanics - 2008
  • Newtonian Mechanics - 2011
  • Newtonian Mechanics - 2014
  • Fluids, Thermodynamics and Optics - 2015
  • Computational Physics - 2015

Contributed Talks

  • Epidemic diffusion in random adaptive networks: effects of quarantine and presence of distinct types of connections - Conference Models in Population Dynamics and Ecology, Brazil (2015)
  • Modeling Social Phenomena: an approach from Statistical Physics - Departament of Physics, Piauí Federal University (2015)
  • How effective are the self-isolation public policies of infected individuals? - Oswaldo Cruz Foundation, Brazil (2015)
  • How can Statistical Physics contribute to Social Sciences? - Institute of Physics, Fluminense Federal University, Brazil (2015)
  • Natural selection in a model of opinion dynamics - Workshop on Mathematical Methods and Modeling of Biophysical Phenomena, Cabo Frio/RJ (2015)
  • Modeling brazilian proportional elections - International School and Conference on Network Science, Netsci-X, Rio de Janeiro/RJ (2015)
  • Analysis of tax evasion dynamics via an agent-based model - Econofis 2014, Brazil (2014)
  • Dynamics of electoral processes: modeling and data analysis - School of Applied Mathematics, Getulio Vargas Foundation, Brazil (2014)
  • Critical phenomena and universality in models of opinion dynamics with heterogeneous agents - Brazilian Center for Physics Research, Brazil (2014)
  • Influence of contrarian, inflexible and independent individuals in kinetic models of opinion formation - Instituto de Ciencias Exatas, Fluminense Federal University, Brazil (2014)
  • Consequence of self isolation in epidemic spreading in social networks - Institute of Physics, Fluminense Federal University, Brazil (2014)
  • SocioPhysics and EconoPhysics: aplications of statistical physics to socio-economic problems - Department of Mathematics, Pontifical Catholic University of Rio de Janeiro, Brazil (2013)
  • The Peter Principle and the efficiency of an organization - Brazilian School of Public and Business Administration, Getulio Vargas Foundation, Brazil (2013)
  • Modeling rumor spreading in social networks - Department of Physics, Pontifical Catholic University of Rio de Janeiro, Brazil (2013)
  • Phase transitions in a three-state opinion model with heterogeneous agents - XXXVI Brazilian Meeting on Condensed Matter Physics, Brazil (2013)
  • Agent-based models in Sociophyiscs: critical phenomena and universality - Institute of Physics, Fluminense Federal University, Brazil (2013)
  • The Neuron and the Hodgkin-Huxley model - Event of Neuroscience, Mathematics and Applied Social Sciences, Getulio Vargas Foundation, Brazil (2013)
  • Epidemic dynamics in Social networks: when diversity makes us more vulnerable - School of Applied Mathematics, Getulio Vargas Foundation, Brazil (2013)
  • Statistical physics of social dynamics - 3rd Summer School, Department of Physics, Pontifical Catholic University of Rio de Janeiro, Brazil (2013)
  • Critical behavior of an epidemic model with time-dependent infection rate - XXX Encontro de Físicos do Norte e Nordeste, Brazil (2012)
  • Phase transition in opinion models - I Workshop of Complex Systems, Fluminense Federal University, Brazil (2012)
  • Computer simulation and modeling of systems of social and biological interest - School of Applied Mathematics, Getulio Vargas Foundation, Brazil (2012)
  • Are self-isolation policies actually effective in epidemic control? - XXXV Brazilian Meeting on Condensed Matter Physics, Brazil (2012)
  • Nonequilibrium phase transitions in opinion models - Department of Physics, Ceara Federal University, Brazil (2012)
  • The Sznajd model with limited persuasion: competition between high-reputation and hesitant agents - Conference of Sociophysics: do humans behave like atoms? , Ecole Polytechnique, Paris, France (2011)
  • Statistical physics applied to nonphysical systems: sociology and epidemiology - Department of Physics, Pontifical Catholic University of Rio de Janeiro, Brazil (2011)
  • Critical behavior of the majority-vote model with diffusion - Institute of Physics, Fluminense Federal University, Brazil (2011)
  • Effects of mass media on opinion spreading in the Sznajd sociophysics model - Institute of Physics, Fluminense Federal University, Brazil (2011)
  • Consequence of reputation in the Sznajd sociophysics model: spontaneous emergence of democratic states - Brazilian Meeting, Foz do Iguaçu/PR, Brazil (2011)
  • Critical behavior of the SIS model with decaying infection rate - Institute of Physics, Fluminense Federal University, Brazil (2010)
  • Efects of reputation in the opinion dynamics of the Sznajd model - Institute of Physics, Fluminense Federal University, Brazil (2010)
  • Nonequilibrium phase transitions in Ising models with conflicting dynamics - XXVIII Encontro de Fisicos do Norte e Nordeste, Brazil (2010)
  • Optimization in Transportation Networks: occupation transition and fluctuation patterns - Department of Physics, Aveiro University, Portugal (2010)
  • First-order phase transition in a 2D random-field Ising model with conflicting dynamics - XXXII Brazilian Meeting on Condensed Matter Physics, Brazil (2009)
  • Universality breaking in the three-dimensional random field Ising model - Institute of Physics, Fluminense Federal University (2009)
  • Monte Carlo simulation of the 2D Ising model: nonextensive approach - Institute of Physics, Fluminense Federal University, Brazil (2009)
  • Dynamical phase transition in growing networks with aging of sities - Institute of Physics, Fluminense Federal University, Brazil (2008)
  • Topological phase transition and optimal fluxes in transportation networks - Institute of Physics, Fluminense Federal University, Brazil (2008)
  • Tricritical behavior of disordered systems in the presence of random magnetic fields - Institute of Physics, Fluminense Federal University, Brazil (2007)

Contributed Posters

  • The effect of influential groups on the stability of a democracy in the Sznajd sociophysics model - VIIth Brazilian Meeting on Simulational Physics, João Pessoa/PB (2013)
  • Empirical investigation of power-law behavior in modularity based community structures - NetSci: International School and Conference on Network Science, Copenhague/Dinamarca (2013)
  • Dynamics of information spreading in heterogeneous populations - Workshop on Mathematical Methods and Modeling of Biophysical Phenomena, Cabo Frio/RJ (2013)
  • Dynamics of epidemic spreading in adaptive networks with household structure - Workshop on Mathematical Methods and Modeling of Biophysical Phenomena, Cabo Frio/RJ (2013)
  • Qualitative aspects of the phase diagrams of J1-J2 model in the cubic lattice - XXX Encontro de Físicos do Norte e Nordeste, Salvador/BA (2012)
  • Nonequilibrium phase transition in a discrete opinion model with quenched disorder - Brazilian Meeting on Condensed Matter Physics, Águas de Lindóia/SP (2012)
  • Percolation transition in growing networks: competition between aging and preferential attachment - Perspectives and Challenges in Statistical Physics and Complex Systems for the Next Decade, Natal/RN (2011)
  • Effects of mass media on opinion spreading in the Sznajd sociophysics model - Brazilian Meeting 2011, Foz do Iguaçu/PR (2011)
  • Critical behavior of the SIS epidemic model with time-dependent infection rate - Workshop on Mathematical Methods and Modeling of Biophysical Phenomena, Foz do Iguaçu/PR (2011)
  • Efects of reputation in the opinion dynamics of the Sznajd model - II Escola e Conferência em Modelagem Computacional, Volta Redonda/RJ (2010)
  • Geometrical phase transitions in growing networks: competition between aging and preferential attachment - XI Latin American Workshop on Nonlinear Phenomena, Búzios/RJ (2009)
  • Finite size analysis of a 2D Ising model within a nonextensive approach - XXXII Brazilian Meeting on Condensed Matter Physics, Águas de Lindóia/SP (2009)
  • Emergence of clusters in growing networks with aging of sites - XXXII Brazilian Meeting on Condensed Matter Physics, Águas de Lindóia/SP (2009)
  • Topological Phase Transition and Optimal Fluxes in Transportation Networks - Conference on Computational Physics, Ouro Preto/MG (2008)
  • Tricritical Points in Magnetic Models under Continuous-Distribution Random Magnetic Fields - XXV Regional Meeting on Physics, Natal/RN (2007)

Served as Reviewer

  • Physics Letters A
  • Physical Review E
  • Physica A
  • International Journal of Modern Physics C
  • Physical Review Letters
  • IEEE Journal of Selected Topics in Signal Processing
  • Journal of Magnetism and Magnetic Materials
  • International Journal of Modern Physics B
  • Revista Boliviana de Física
  • Journal of Physics A: Mathematical and Theoretical
  • Journal of Physics D: Applied Physics
  • Journal of Physics: Condensed Matter
  • Journal of Dynamics and Games
  • Journal of Statistical Mechanics

Member of Editorial Board

  • Multi-disciplinary Journal Heliyon, from Elsevier

Brazilian Music

Images

Contact

Instituto de Física
Universidade Federal Fluminense
Av. Litorânea s/n, CEP 24210-340
Niterói - Rio de Janeiro
E-mail: nuno@if.uff.br, nuno@mail.if.uff.br
Room: 419, new building of Institute of Physics
Phone: +55 (21) 2629-5845

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