Research

The Biological Complexity Unit studies how stochastic fluctuations influence the dynamics of biological systems, and the strategies implemented by biological systems to cope with these fluctuations. We aim at understanding of these phenomena by means of theoretical methods and computational approaches from non-equilibrium statistical physics.

Information processing in cells

Biological functions at the sub-cellular level are often performed with remarkable accuracy and speed, despite the presence of thermal fluctuations. We are interested in understand the physical limits to the performance of these processes in terms of speed, error and dissipation. We are also studying specific enzymes such as DNA polymerases and ribosomes, to understand whether they operate close to these limits.

Selected recent publications​
  • D. Chiuchiù, Y. Tu, S. Pigolotti, "Error-speed correlations in biopolymer synthesis", Phys. Rev. Lett. 123, 038101, arXiv:1905.12869  (2019).
  • M. Cencini, S. Pigolotti, "Energetic funnel facilitates facilitated diffusion", Nucleic Acid Research 46(2), 558-567 (2018).
  • P. Sartori and S. Pigolotti. “Thermodynamics of error correction”. Phys. Rev. X, 5:041039, 2015.
  • P. Sartori and S. Pigolotti. “Kinetic vs. energetic discrimination in biological copying”. Phys. Rev. Lett., 110:188101, 2013.

 

Population dynamics

Ecosystems display a remarkable degree of spatial organization. The impact of their spatial dynamics on biodiversity can be studied by exploiting analogies with non-equilibrium physical systems. We are interested in predicting biodiversity patterns in ecosystems characterized by a complex structure, such as communities of microorganisms inhabiting marine ecosystems. We are also exploring how other classic ecological and evolutionary mechanisms, such as the possibility of adopting a "bet-hedging" strategy against a fluctuating environment, are modified by the presence of spatially-structured environments.

Selected recent publications​
  • P.V Martín, A. Bucek, T. Bourguignon, S. Pigolotti, "Ocean currents promote rare species diversity in protists", bioRxiv preprint , Science Advances 6(29), eaaz9037 (2020).
  • S. Pigolotti, M. Cencini, D. Molina, M.A. Muñoz, "Stochastic spatial models in ecology: a statistical physics approach", J. Stat. Phys. 1-30, preprint arXiv:1708.03475 (2018).
  • S. Pigolotti and R. Benzi. “Selective advantage of diffusing faster”. Phys. Rev. Lett., 112:188102, 2014.
  • S. Pigolotti, R. Benzi, M. H. Jensen, and D. R. Nelson. Population genetics in compressible flows. Phys. Rev. Lett., 108:128102, 2012.

 

Non-equilibrium thermodynamics

Stochastic thermodynamics studies non-equilibrium properties of mesoscopic physical systems. Fluctuation relations are fundamental results in stochastic thermodynamics. They govern non-equilibrium behavior of a vast class of systems and find application in experimentally measuring free energy differences by means of non-equilibrium manipulation protocols. In recent years, we have been discovering several additional universal properties of mesoscopic systems. We are interested in characterizing these novel properties and organize them into a unified theory. 

Selected recent publications​