Probing active forces via a fluctuation-dissipation relation: Application to living cells

Pierre Bohec (1) , François Gallet (1) , Christian Maes (2) , Soghra Safaverdi (2) , Paolo Visco (1) , Frédéric van Wijland (1)

1 MSC - Matière et Systèmes Complexes
2 Instituut voor Theoretische Fysica

We derive a new fluctuation-dissipation relation for non-equilibrium systems with long-term memory. We show how this relation allows one to access new experimental information regarding active forces in living cells that cannot otherwise be accessed. For a silica bead attached to the wall of a living cell, we identify a crossover time between thermally controlled fluctuations and those produced by the active forces. We show that the probe position is eventually slaved to the underlying random drive produced by the so-called active forces.

Domaines: Matière Molle [cond-mat.soft]

Pierre Bohec, François Gallet, Christian Maes, Soghra Safaverdi, Paolo Visco, et al.. Probing active forces via a fluctuation-dissipation relation: Application to living cells. EPL - Europhysics Letters, 2013, 102 (5), pp.50005. ⟨10.1209/0295-5075/102/50005⟩. ⟨hal-00679065v2⟩