Colloidal Heat Engines: Extracting Work from Bacterial Activity and Non-conservative Forces

Seminar: Special Seminar | June 19 | 12-1 p.m. | 106 Stanley Hall

 Ajay K. Sood, Department of Physics, Indian Institute of Science

 College of Chemistry

Abstract: Artificial microscale heat engines are prototypical models to explore the mechanisms of energy transduction in a fluctuation dominated regime. This talk will first discuss our experiments to realize a micrometer sized active Sterling heat engine operating between two nonequilibrium reservoirs with different activities of the bacteria. At high activities of bacteria, the efficiency of our heat engines surpasses the equilibrium saturation limit of Sterling efficiency[1].

A key requirement to achieve performance of macroscopic non-Equilibrium engines, is to build collections of heat engines that perform in unison. In second part of my talk[2], I will discuss our recent experiments on coupling two heat engines in close proximity and demonstrate the synergy. We show that the coupling amplifies the nonequilibrium, non-conservative probability flows. Our work highlights a future direction for the construction of microscopic engines where the irreversibility pathways can be regulated.

(1) S. Krishnamurthy, S. Ghosh, D. Chatterji, R. Ganapathy and A. K. Sood, Nature Physics 12, 1134 (2016)

(2) S. Krishnamurthy, R. Ganapathy and A. K. Sood, To be published (2019)

 pauline.cheng@berkeley.edu