Hernán Alejandro Makse

Professor of Physics
Levich Institute and
Physics Department
City College of New York
Steinman Hall, T1M-12
140th Street and Convent Avenue
New York, NY 10031-9198
(212) 650-6847, (212) 650-6835 (fax)
hmakse at lev.ccny.cuny.edu

Hernan email

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Welcome to the Complex Networks and Soft Matter lab of Hernán Makse at the Levich Institute and Department of Physics of City College of New York in New York City. We are interested in the theoretical understanding of complexity. We are working towards the development of new arquitectural laws for complex networks, from biological systems, to the Internet, the web, to social networks and cities. We also focus on the study of jammed matter, spanning from granular materials, colloidal suspensions, dense emulsions to glasses in search of unifying theoretical frameworks. We explore this variety of out of equilibrium systems in terms of their behavior as they experience structural arrest or jamming. The group focuses on the theoretical and computational approaches in parallel with experiments.

Our research is related to "emergent properties", i.e., "properties not contained in the simple laws of physics, although they are a consequence of them".

Top cited articles in Google Scholar profile.

There are openings for graduate students and postdocs to work on granular matter and complex networks, broadly considered. For an account of the daily routine for students in our lab, see the report of Louis Portal, research intern from France.

Short bio: Hernan Makse currently serves as Professor of Physics at CUNY in New York City, wherein he is responsible for the Complex Networks and Soft Matter lab at the Levich Institute. He holds a PHD degree in Physics from Boston University. He has been author of numerous publications on the theory of complex systems and the physics of granular materials. He has visited over 50 countries in the world and whenever he travels, he usually attends a concert at the main Arts Center of the city and enjoys the local culture. He loves jazz, classic literature and opera and he is an avid footballer.

Introduction to research in complex networks: See a feature article in the Journal of Student Research.

Introduction to research in soft matter: See a Highlight Article in Soft Matter.

Presentations on granular matter, colloidal glasses and emulsions, jamming transition, effective temperature in granular matter, Edwards statistical mechanics of jammed matter, random close packing (RCP), polydisperse, non-spherical packing and cavity methods for force propagation, nonlinear elasticity of granular matter, fractal complex networks and renormalization group, protein and social networks, and urban economics and cities, and big data. To download data and computer codes for: (a) Molecular Dynamics (DEM) of granular matter, (b) fractal analysis of complex networks, (c) Clustering Analysis of cities, (d) experimental data on colloids and glasses, (e) generating sequences with long-range correlations, (f) calculating all minima and transition states of the energy landscape in small clusters of LJ and Hertz particles, (g) hard sphere packing from RLP to FCC, (h) fMRI brain data, (i) obesity and cancer spreading, and (j) spreading of disease and information [Twitter, Facebook, LiveJournal and APS] visit SOFTWARE AND DATA.

SCIENCE BLOG:

  • February 2014. Highlights in Soft Matter: Fundamental challenges in packing problems: from spherical to non-spherical particles

    by Adrian Baule and Hernan Makse. Random packings of objects of a particular shape are ubiquitous in science and engineering. However, such jammed matter states have eluded any systematic theoretical treatment due to the strong positional and orientational correlations involved. In recent years progress on a fundamental description of jammed matter could be made by starting from a constant volume ensemble in the spirit of conventional statistical mechanics. Recent work has shown that this approach, first introduced by S. F. Edwards more than two decades ago, can be cast into a predictive framework to calculate the packing fractions of both spherical and non-spherical particles. Soft Matter Advance publication (2014); DOI: 10.1039/C3SM52783B. pdf
  • February 2014. Large cities are less green but help to reduce suicidal rates

    . Work done in colaboration with Jose S. Andrade from Universidade Federal de Ceara, Brazil. Large cities are more productive than small ones so it shouldn't come as a surprise that they produce more CO2 as well, say physicists. See press coverage at MIT Technology Review and Arizona News. Original article: Oliveira, E.A., Andrade, J.S. & Makse, H.A. Large cities are less green. Sci. Rep. 4, 4235; DOI:10.1038/srep04235 (2014), pdf. At the same time, the science of cites shows that bigger cities have fewer suicides per capita than smaller ones. Our new study shows that residents of bigger cities are less likely to commit suicide, suggesting the lonely find solace among increased opportunity for social interaction. Computational anthropologists Melo, Moreira, Makse and Soares suggest that the kind of emotional intensity associated with suicide might dissipate more easily in big cities, where there are more people to shoulder the burden, an idea known as emotional epidemy. Put another way, suicides are essentially a social phenomenon. See full article in the Arxiv and press coverage at MIT Technology Review. See also Medical Daily, The Guardian and the piece of Olga Khazan in The Atlantic: Hell might be other people, but they might just save you from yourself.


  • July 2013. Mean-field theory of random close packings of axisymmetric particles

    by Adrian Baule, Romain Mari, Lin Bo, Louis Portal, Hernan A. Makse. Finding the densest random packing of particles with a non-spherical shape is a long standing mathematical problem. Here, the authors develop a method based on a mean-field estimation of the Voronoi volume which can predict densest random packings in good agreement with empirical results. Date 23 Jul 2013 doi: 10.1038/ncomms3194. Nature Communications 4, Article number: 2194 doi:10.1038/ncomms3194. pdf


  • March 2013. Novel insights into the evolution of protein networks.

    March 21, 2013. Paper in PLOS ONE. System-wide networks of proteins are indispensable for organisms. Function and evolution of these networks are among the most fascinating research questions in biology. Bioinformatician Thomas Rattei, University of Vienna, and physicist Hernan Makse, City University New York (CUNY), have reconstructed ancestral protein networks. The results are of high interest not only for evolutionary research but also for the interpretation of genome sequence data. Read more at: Phys.org. Full dataset of reconstructed ancestral protein interaction networks available here.


  • Nov 2012. Hernan Makse is elected a Fellow of the American Physical Society

    Dr. Hernan Makse's APS citation reads:

    "For his contributions to a broad range of topics in non-equilibrium systems ranging from urban dynamics and complex networks to statistical mechanics of jammed matter, in particular, the elucidation of the random close packing state of granular matter."

    The overarching theme of Dr. Makse's research is the theoretical understanding of complexity. Dr. Makse's original area of interest is the study of jammed matter, spanning from granular materials, colloidal suspensions, dense emulsions to glasses, in search of unifying theoretical frameworks. Under his 2003 NSF CAREER award, he studied statistical mechanics of particulate systems far from equilibrium. He is, however, continually coming up with new applications for the laws of physical systems, and by 2005, he was studying the dynamics of social networks under NSF auspices. Dr. Makse continues his groundbreaking work on granular matter, and, increasingly, he is applying the principles of statistical mechanics to the organization of complex networks from biological systems, to urban economics and social networks. This interdisciplinary work is at the interface of physics and disciplines such as neuroscience, biology and sociology. In recent papers he has addressed the function and evolution of protein networks, the environmental factors which may affect the spread of obesity, what makes the best spreaders of information in a social network, and a new way to define cities based on clustering algorithms from percolation theory. Dr. Makse travels the world in search of collaborators willing to take the same intellectual risks he does, and his lab at CCNY's Benjamin Levich Institute is home to graduate students from China, Brazil, Argentina, Chile, France, Italy and the like.


  • June 2012. Online social interactions

    What are our motivations in choosing our online friends? In our recent paper in PRX we study high-quality data and show how we can estimate the influence of different social drivers. In simpler words, how probable is it that we reply to friend requests or how often do we connect to popular people? Although we may not realize this, our connections evolve and we may find ourselves in an environment different from our choices. Physics Review X 2, 031014 (2012). pdf


  • April 2012. Environmental factors may affect the spread of obesity

    Paper in Scientific Reports. Press release: An international team of researchers' study of the spatial patterns of the spread of obesity suggests America's bulging waistlines may have more to do with collective behavior than genetics or individual choices. The team, led by City College of New York physicist Hernaán Makse, found correlations between the epidemic's geography and food marketing and distribution patterns. Talk at the Wolfram Data Summit 2012. Press Releases: CCNY. NSF Highlights. Science Daily. Medicalxpress. Science Blog. Supermarket or not Supermarket (Care2.com). The visible embryo. The Atlantic cities. Jeff Nesbit's "On the Edge" blog in US News. Dataset available here.


  • Feb 2012. The conundrum of brain networks: small-world or fractal modularity?

    Paper. Dataset of brain networks and computer codes for network analysis available here. Published in PNAS, Feb. 20 (2012).


  • Nov 2010. Connections aren't everything.

    Who are the best spreaders of information in a social network? Best connected individuals may not be the most influential spreaders. Instead, location in the network, as defined by the k-shell, determines influence. Click here for more information and dataset 1 and dataset 2: Twitter, Facebook, LiveJournal and full APS collaboration network. Paper: pdf or cond-mat. Press releases: Technology review, Science Daily, Fast company, Science for SEO, Emedia, NSF, India Times. Collaboration between Bar-Ilan University, Boston University, Stockholm University, NYU, and CCNY. Nature Physics 2010. (High resolution image and cover, created with the lanet-vi tool).


  • Definition of random close packing of granular matter in the Edwards thermodynamic framework.

    Physica A 2010. The codes to generate hard spheres packing from random loose packing to FCC can be downloaded here.


  • Fractal babies:

    We investigate the network of human cell differentiation from the fertilized egg up to a crying baby. PNAS, 2010. Dataset of cell types. The full network is published in the Supporting Information in PNAS.


  • Zipf's Law for all cities, large and small.

    The City Clustering Algorithm, CCA, allows for a test of Zipf's law for cities of all sizes. We find (ta,tan,ta,tan..) that Zipf's law is surprisingly valid up to small cities of a few hundred inhabitants. Collaboration with Xavier Gabaix, Stern, NYU. Paper on Zipf's law for all cities. Published in American Economic Review, August 2011. Below is an image of all the population clusters identified by the CCA in the USA and the CCA cluster around London superimposed with a Google maps.


  • Statistical patterns in human communication and growth of cities.

    We find scaling laws in human communication patterns (PNAS).
    A recent paper presents a new way to define cities based on clustering algorithms from percolation theory. We find that the growth rate of cities and its standard deviation follow (surprise, surprise..) power-laws with the city size, in contradiction to Gibrat's law.


  • Renormalization Group analysis in fractal complex networks

    The small world-fractal transition and information flow. See recent paper in Phys. Rev. Lett. 2010.


  • Work on random close packing.

    Paper in the Nature issue of May 29, 2008, and Supplementary Materials. News & Views editorial by Zamponi. Press release. Nature Physics: Research Highlights, p435. Physics World. Science Daily. Physorg.com. Genetic Engineering & Biotechnology News.

    The following follow up papers are in Physica A and in cond-mat: Jamming I: A Hamiltonian for jammed matter. Jamming II: A phase diagram for jammed matter. Jamming III: Characterizing Randomness via the Entropy of Jammed Matter. Jamming IV: A distribution of volumes and coordination number in jammed matter: mesoscopic approximation. Jamming V: Jamming in two dimensions.


  • Hernan Makse is honored by the Mayor of New York City

    with the Mayor's Award for Excellence in Science and Technology to Young Investigator for playing with sand [press release of the New York Academy of Science, newspaper, pdf, faculty spotlight].


  • How to calculate the fractal dimension of a complex network: the box covering algorithm.

    Can you improve the box-covering of a network? Download the algorithms and Databases of complex networks used in our studies to calculate the fractal dimension of a complex network. Including our PNAS paper on Scaling Theory of Transport in Complex Biological Networks in the May 2007 issue (pdf, supplementary information).


  • Colloids aging at equilibrium.

    Explanation. From the August 2006 issue of Nature Physics.

    [Colloidal Glass] [PPT][Teff]

    [Movie1][Movie2] [Data]


  • Origin of fractality in complex networks.

    Our advice: Be fractal and be robust. From the April 2006 issue of Nature Physics.


  • Self similar Complex networks:

    Explanation of self-similarity of Complex Networks. What is the relation between these Romanesque broccoli and the protein-protein interaction network of E.coli? From the January 2005 issue of Nature.


  • Romanesque networks:
  • News and Views Editorial by Strogatz on Self-similar Complex Networks in the January 27th, 2005 issue of Nature.


  • Research on thermodynamics of jamming:

    Simulations and experiments to investigate the statistical mechanics of jammed particulate matter.


  • Measuring the temperature of sand:

    Explanation.


  • Statistical Mechanics of Jammed Matter:

    Jamming is even cooler than you thought. A review article by H. A. Makse, J. Brujic and S. F. Edwards.


  • Jamming in a box:

    See a recent News Feature in the October 19th, 2003 issue of Nature.


  • Taking the temperature of sand:

    A News and Views Nature Editorial by Bob Behringer in Nature.



  • Oct 1995. New ways of looking at cities.

    Hernan Makse's first scientific paper (well, second, after a small paper on dyslexic behavior in neural networks published in 1992). It was published in Nature on October 19, 1995. The study models the morphologies of cities in terms of correlated percolation and proposes a new way to look at cities, in the words of Michael Batty in the attached commentary in Nature published in New and View.

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