Research

Research highlight in Physical Review Letters

Interactions of colloidal particles can be tuned over a wide range. Truly long-range interactions (like gravity) are possible through solvent flow. In this work we demonstrate that colloidal ion reservoirs produce such flows that are well-described as a conservative potential, predicting the dynamics and structure of clusters of a few particles ("molecules"). Read article...

"Self-assembly of colloidal molecules due to self-generated flow" by R. Niu, T. Palberg, and T. Speck, published in Phys. Rev. Lett. 119, 028001 (2017)

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Stochastic thermodynamics

Introduction

Stochastic thermodynamics has become a comprehensive framework to describe driven (mesoscopic) systems governed by stochastic dynamics. The key concepts are the identification of fluctuating work, heat, and entropy. We use these concepts in our research (e.g., on active matter and coarse-graining) as the theoretical foundations to describe driven matter.

Transport coefficients

One area in which stochastic thermodynamics has contributed is the linear response theory for small perturbations of non-equilibrium steady states (in contrast to the conventional perturbation of equilibrium states). Based on these results we develop new algorithms and methods to determine transport coefficients from numerical simulations both close and far from thermal equilibrium.

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Research highlight in Nature Physics

A study of a composite soft-matter nanomechanical system consisting of a rotating ring of optically trapped colloidal particles confining a set of untrapped colloids demonstrates the possibility of gearwheel-like torque transmission on the nanoscale. Read article...

"Transmission of torque at the nanoscale" by Ian Williams, Erdal C Oguz, Thomas Speck, Paul Bartlett, Hartmut Löwen and C. Patrick Royall

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