# Boosting the performance of the Quantum Otto heat engines

## TL;DR

This paper investigates how oscillations in extra work during finite-time quantum adiabatic processes affect the performance of quantum Otto engines, and proposes optimized control schemes to enhance power and efficiency.

## Contribution

It demonstrates the impact of oscillating extra work in simple quantum systems and introduces control schemes that improve engine performance over linear control.

## Key findings

- Oscillating extra work causes jagged power-efficiency relations.
- Optimized control times can utilize oscillations to boost power and efficiency.
- Special control schemes can achieve zero extra work at specific times.

## Abstract

To optimize the performance of a heat engine in finite-time cycle, it is important to understand the finite-time effect of thermodynamic processes. Previously, we have shown that extra work is needed to complete a quantum adiabatic process in finite time, and proved that the extra work follows a \mathcal{C}/\tau^{2} scaling for long control time \tau. There the oscillating part of the extra work is neglected due to the complex energy-level structure of the particular quantum system. However, such oscillation of the extra work can not be neglected in some quantum systems with simple energy-level structure, e. g. the two-level system or the quantum harmonic oscillator. In this paper, we build the finite-time quantum Otto engine on these simple systems, and find that the oscillating extra work leads to a jagged edge in the constraint relation between the output power and the efficiency. By optimizing the control time of the quantum adiabatic processes, the oscillation in the extra work is utilized to enhance the maximum power and the efficiency. We further design special control schemes with the zero extra work at the specific control time. Compared to the linear control scheme, these special control schemes of the finite-time adiabatic process improve the maximum power and the efficiency of the finite-time Otto engine.