Rapid optimal work extraction from a quantum-dot information engine

TL;DR

This paper demonstrates optimized protocols for a quantum-dot Szilard engine that efficiently extract work from thermal fluctuations across various driving speeds, highlighting trade-offs between power and fluctuations.

Contribution

It introduces a family of optimized protocols for quantum-dot engines that improve power and efficiency across different driving regimes, addressing a key challenge in nanoscale thermodynamics.

Findings

Optimized protocols significantly improve power and efficiency.

Fast driving increases power fluctuations when optimizing for efficiency.

Engine performance varies across different driving speeds.

Abstract

The conversion of thermal energy into work is usually more efficient in the slow-driving regime, where the power output is vanishingly small. Efficient work extraction for fast driving protocols remains an outstanding challenge at the nanoscale, where fluctuations play a significant role. In this Letter, we use a quantum-dot Szilard engine to extract work from thermal fluctuations with maximum efficiency over two decades of driving speed. We design and implement a family of optimised protocols ranging from the slow- to the fast-driving regime, and measure the engine's efficiency as well as the mean and variance of its power output in each case. These optimised protocols exhibit significant improvements in power and efficiency compared to the naive approach. Our results also show that, when optimising for efficiency, boosting the power output of a Szilard engine inevitably comes at the cost of increased power fluctuations.