# Operationally accessible bounds on fluctuations and entropy production in periodically driven systems

## TL;DR

This paper derives experimentally accessible bounds on entropy production and fluctuations in periodically driven systems, enabling estimation of thermodynamic efficiency without detailed system knowledge.

## Contribution

It introduces inequalities linking entropy production to measurable data, including bounds based solely on state occupancy times, applicable to various driven systems.

## Key findings

- Entropy production can be bounded using state occupancy times.
- Thermodynamic efficiency bounds are derived from experimental data.
- Results are demonstrated on a three-level system and colloidal Stirling engine.

## Abstract

For periodically driven systems, we derive a family of inequalities that relate entropy production with experimentally accessible data for the mean, its dependence on driving frequency, and the variance of a large class of observables. With one of these relations, overall entropy production can be bounded by just observing the time spent in a set of states. Among further consequences, the thermodynamic efficiency both of isothermal cyclic engines like molecular motors under a periodic load and of cyclic heat engines can be bounded using experimental data without requiring knowledge of the specific interactions within the system. We illustrate these results for a driven three-level system and for a colloidal Stirling engine.