Stochastic dynamics of single molecules across phase boundaries

Statistical Physics and Complexity Group meeting

Stochastic dynamics of single molecules across phase boundaries

  • Event time: 3:00pm until 4:00pm
  • Event date: 2nd November 2021
  • Speaker: Stefano Bo (Max Planck Institute for the Physics of Complex Systems)

Event details

We discuss the stochastic trajectories of single molecules in a phase-separated liquid, when a dense and a dilute phase coexist. Starting from a continuum theory of macroscopic phase separation we derive a stochastic Langevin equation for molecular trajectories that takes into account thermal fluctuations. We find that molecular trajectories can be described as diffusion with drift in an effective potential, which has a steep gradient at phase boundaries. We discuss how the physics of phase coexistence affects the statistics of molecular trajectories and in particular the statistics of displacements of molecules crossing a phase boundary. We also investigate the consequences of thermodynamic equilibrium on the statistics of single molecule trajectories and the changes brought about by non-equilibrium conditions. Bridging between single-molecule dynamics and collective dynamics at macroscopic scales we provide a framework to study single-molecule dynamics in phase-separating systems, which can be used to infer key phase separation parameters from the statistics of single-molecule trajectories.