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Published on: March 5, 2021
Memory-aware acceleration of orientational dynamics in nanoparticle suspensions.
Miguel Ibáñez García1, Raúl Rica1, María Luisa Luisa Jiménez Olivares1
1Universidad de Granada, Department of Applied Physics and Research Unit 'Modeling Nature' (MNat), Nanoparticle Trapping Laboratory, Granada, Spain.
Summary
Researchers observed nonmonotonic relaxation in nanoparticle electro-orientation, revealing memory effects that limit dynamics. They developed new protocols to overcome these memory effects, significantly reducing relaxation times in stochastic systems.
Area of Science:
- Physics
- Materials Science
- Chemistry
Background:
- Stochastic systems exhibit speed limits and memory effects that impede dynamics after perturbations.
- Non-spherical nanoparticles' electro-orientation is a model system for studying relaxation dynamics.
Purpose of the Study:
- To demonstrate Kovacs-type nonmonotonic relaxation in nanoparticle electro-orientation.
- To investigate how memory effects limit simple acceleration protocols.
- To design and validate new protocols for mitigating memory effects and accelerating dynamics.
Main Methods:
- Optical monitoring of orientational dynamics via field-induced birefringence.
- Theoretical modeling using the Smoluchowski equation for orientational probability density.
- Development and experimental testing of novel multi-step relaxation protocols.
Main Results:
- Observed characteristic Kovacs shoulder in relaxation dynamics under a matched two-step protocol.
- Identified nanoparticle polydispersity as the origin of multiscale relaxation and memory effects.
- Demonstrated substantial reductions in relaxation time using designed protocols compared to standard methods.
Conclusions:
- Memory effects in stochastic systems arise from the interplay of multiple degrees of freedom and control parameters.
- Novel protocols effectively mitigate memory effects by sequentially suppressing slow relaxation modes.
- The findings offer an experimentally accessible strategy for controlling multiscale stochastic dynamics.
