# Exact simulation of classical heat engine cycles using single-ion phonon laser

## TL;DR

Researchers used a single ion to simulate heat engine cycles, achieving clearer results by controlling phonon vibrations.

## Contribution

They demonstrated classical thermodynamic cycles at the single-ion level using a phonon laser.

## Key findings

- The Otto and Carnot cycles were simulated with high signal-to-noise in a single ion.
- Phonon laser control suppressed thermal fluctuations, enabling clearer results.
- Maximum efficiencies of the cycles were compared by monitoring vibration amplitude and frequency.

## Abstract

Heat engines are essential devices in modern industry, converting heat energy into useful mechanical work via their working substances. Here we experimentally simulate the conventional heat engine by employing the vibrational mode of a single trapped ion as the working substance. In contrast to simply employing the ion in thermal motion, we consider coherently stimulating the ion’s vibrational motion as the phonon laser, which helps acquire clearer results by effectively suppressing the thermal fluctuation. As such, we demonstrate in an exact and high signal-to-noise way the standard steps of both the Otto and Carnot cycles in a single ion, and compare their maximum efficiencies by monitoring the amplitude and frequency of the vibration. Our work witnesses an interesting single-atom thermal engine using coherently controlled phonons. It would be the smallest platform for simulating or demonstrating classical thermodynamic laws and phenomena at a single ion scale via optical manipulation techniques for phonon lasers.