Year: 2019
Type: article
Abstract: Since Albert Einstein's seminal 1905‐paper on Brownian motion, the temperature of fluids and gases of known viscosity can be deduced from observations of the fluctuations of small suspended probe particles. We summarize recent generalizations of this standard technique of Brownian thermometry to situations involving spatially heterogeneous temperature fields and other non‐equilibrium conditions in the solvent medium. The notion of effective temperatures is reviewed and its scope critically assessed. Our emphasis is on practically relevant real‐world applications, for which effective temperatures have been explicitly computed and experimentally confirmed. We also elucidate the relation to the more general concept of (effective) temperature spectra and their measurement by Brownian thermospectrometry. Finally, we highlight the conceptual importance of non‐equilibrium thermometry for active and biological matter, such as microswimmer suspensions or biological cells, which often play the role of non‐thermal (“active”) heat baths for embedded Brownian degrees of freedom.
Source: ChemSystemsChem
Authors: Daniel Geiß, Klaus Kroy
Language: English
Subfield: Statistical and Nonlinear Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,030
Award: G1490321708
OpenAlex ID: W2984586907