Geometry of work fluctuations versus efficiency in microscopic thermal machines

TL;DR

This paper introduces a thermodynamic geometric approach to optimize efficiency and work fluctuations in microscopic thermal machines, applicable to classical and quantum systems, with a focus on Gaussian machines.

Contribution

It develops a general multi-objective optimization method for efficiency and fluctuations, and characterizes optimal protocols for Gaussian microscopic machines.

Findings

Optimal protocols are derived for Gaussian systems.

The method applies to both classical and quantum regimes.

Thermodynamic length guides protocol optimization.

Abstract

When engineering microscopic machines, increasing efficiency can often come at a price of reduced reliability due to the impact of stochastic fluctuations. Here we develop a general method for performing multi-objective optimisation of efficiency and work fluctuations in thermal machines operating close to equilibrium in either the classical or quantum regime. Our method utilises techniques from thermodynamic geometry, whereby we match optimal solutions to protocols parameterised by their thermodynamic length. We characterise the optimal protocols for continuous-variable Gaussian machines, which form a crucial class in the study of thermodynamics for microscopic systems.