Quantum Otto Thermal Machines Powered by Kerr Nonlinearity

TL;DR

This paper demonstrates that Kerr nonlinearity in quantum Otto engines significantly enhances efficiency and refrigeration performance, surpassing harmonic oscillator-based engines using realistic superconducting circuit parameters.

Contribution

It introduces the use of Kerr nonlinearity in quantum Otto cycles, showing substantial improvements in efficiency and cooling performance over traditional harmonic oscillator engines.

Findings

Efficiency can be increased up to 2.5 times with Kerr nonlinearity.

Refrigerator performance can be tripled using Kerr nonlinearity.

Results are based on realistic circuit quantum electrodynamics parameters.

Abstract

We study the effect of Kerr nonlinearity in quantum thermal machines having a Kerr-nonlinear oscillator as working substance and operating under the ideal quantum Otto cycle. We first investigate the efficiency of a Kerr-nonlinear heat engine and show that by varying the Kerr-nonlinear strength the efficiency surpasses in up to 2.5 times the efficiency of a quantum harmonic oscillator Otto engine. Moreover, the Kerr-nonlinearity makes the coefficient of performance of the Kerr-nonlinear refrigerator to be as large as 3 times the performance of quantum harmonic oscillator Otto refrigerators. These results were obtained using realistic parameters from circuit quantum electrodynamics devices formed by superconducting circuits and operating in the microwave regime.