Experimental Evidence for Strong Emergent Correlations between Particles in a Switching Trap

Area of Science:

• Statistical mechanics
• Soft matter physics
• Non-equilibrium systems

Background:

• Brownian motion describes random particle movement due to thermal fluctuations.
• Harmonic traps confine particles, and their stiffness can be altered.
• Non-equilibrium systems lack detailed balance, leading to complex dynamics.

Purpose of the Study:

• To experimentally investigate a system of four two-dimensional Brownian particles.
• To analyze the impact of simultaneously switching trap stiffness on particle behavior.
• To determine if hydrodynamic interactions influence observable statistics in this driven system.

Main Methods:

• Utilizing a system of N=4 two-dimensional Brownian particles.
• Confining particles in harmonic traps with stiffness that switches randomly.
• Measuring particle positions and analyzing correlations, extreme value statistics, and full counting statistics.

Main Results:

• The system reaches a non-equilibrium stationary state with long-range correlations.
• Certain observable statistics are insensitive to hydrodynamic interactions.
• Experimental data shows excellent agreement with theoretical predictions for noninteracting particles.

Conclusions:

• Hydrodynamic interactions do not universally affect all statistical observables in this driven system.
• Noninteracting theories can accurately describe specific properties of interacting Brownian particles under these conditions.
• The study highlights the emergence of universal behavior in driven soft matter systems.