Direct verification of the fluctuation-dissipation relation in viscously coupled oscillators

Abstract

The fluctuation-dissipation relation, a central result in non-equilibrium statistical physics, relates equilibrium fluctuations in a system to its linear response to external forces. Here we provide a direct experimental verification of this relation for viscously coupled oscillators, as realized by a pair of optically trapped colloidal particles. A theoretical analysis, in which interactions mediated by slow viscous flow are represented by non-local friction tensors, matches experimental results and reveals a frequency maximum in the amplitude of the mutual response which is a sensitive function of the trap stiffnesses and the friction tensors. This allows for its location and width to be tuned and suggests the utility of the trap setup for accurate two-point microrheology.

arXiv comment8 pages and 8 figures

References in corpus (8)

• Stochastic thermodynamics, fluctuation theorems, and molecular machines
• Theoretical perspective on the glass transition and amorphous materials
• How far from equilibrium is active matter?
• One- and two-particle microrheology
• Non-equilibrium and information: the role of cross-correlations
• The fluctuation-dissipation relation: how does one compare correlation functions and responses?
• Stationary and transient Fluctuation Theorems for effective heat flux between hydrodynamically coupled particles in optical traps
• Universal hydrodynamic mechanisms for crystallization in active colloidal suspensions

Cited by in corpus (4)

• Two-point active microrheology in a viscous medium exploiting a motional resonance excited in dual-trap optical tweezers
• Single-shot wideband active microrheology of viscoelastic fluids using pulse-scanned optical tweezers
• Role of interactions in non-equilibrium transformations
• Irreversibility of mesoscopic processes with hydrodynamic interactions