Asymmetric Heating and Cooling in Microscale Systems

This article presents a study on the thermal relaxation processes of microscale systems, specifically focusing on the asymmetry between heating and cooling. It documents the findings from experiments using optically trapped colloidal particles to demonstrate that heating occurs faster than cooling when subjected to temperature changes. The research introduces a new theoretical framework termed 'thermal kinematics' to explain these phenomena. The results challenge conventional thermodynamic assumptions by showing that the pathways for heating and cooling are fundamentally distinct, particularly when systems are pushed far from thermodynamic equilibrium. The article outlines three key asymmetries observed during the experiments, including the unexpected efficiency of entropy production during heating compared to heat dissipation during cooling. The implications of these findings are significant for energy-conversion applications and the thermal management of microscopic devices, particularly in the context of Brownian heat engines. Overall, the study contributes to a deeper understanding of non-equilibrium thermodynamics at the microscale.