Colloquium
Department of Physics, NCU
A Colloidal Heat Engine beyond Classical limit
Prof. Yonggun Jun
Department of Physics, NCU
Date 2021.03.30 (Tue)
Place S4-625
Time 13:30-15:00
Abstract: The heat engine is a mechanical transducer to convert heat into mechanical energy and has been a cornerstone concept in Classical Thermodynamics. For the last two decades, the advance of the miniaturization technique allows developing the micro-scale machines. Of interest are the colloidal heat engines made of a Brownian particle confined with periodically modulated harmonic potential and contacted with the heat bath. Surprisingly, one study reported that the efficiency of the microscopic heat engine subject to the bacterial bath could surpass the thermodynamic limit. The physical reason for outperformance is, however, still unclear. Motivated from this, we demonstrate the active bath heat engine of a colloidal particle in contact with the non-equilibrium heat bath with correlated noises. We modulate the width of the harmonic potential and the strength of the artificial correlated noise using the optical feedback trap of high precision position detection and ultra-fast control. When the efficiency of the active bath heat engine is compared to that of a counter-passive heat engine with the same temperature difference, we find that the stiffness-dependent correlated noise can enhance the efficiency higher than the classical thermodynamic limit of passive engines. Our result will suggest a new insight into understanding the better performance of nano-machines and biological motors.