Embedded Quantum Correlations in thermalized quantum Rabi systems

TL;DR

This paper investigates how quantum correlations in open quantum Rabi systems vary with parameters like coupling strength, qubit number, and temperature, and how these correlations influence quantum heat engine performance.

Contribution

It provides the first detailed numerical analysis of embedded quantum correlations in multi-qubit Rabi systems and their impact on work extraction in quantum heat engines.

Findings

Quantum correlations peak at specific coupling strengths depending on system size and temperature.

Maximum extractable work correlates with the peak of embedded quantum correlations.

Increasing qubits shifts the optimal coupling strength for maximum work to smaller values.

Abstract

We study the quantum correlations embedded in open quantum Rabi systems. Specifically, we study how the quantum correlation depends on the coupling strength, number of qubits, and reservoir temperatures. We numerically calculate the quantum correlations of up to three qubits interacting with a single field mode. We find that the embedded quantum correlations exhibit a maximum for a given coupling strength, which depends inversely on the number of subsystems and the reservoir temperature. We explore how this feature affects the performance of a many-qubit Otto heat engine, finding numerical evidence of a direct correspondence between the minimum of the extractable work and the maximum of the embedded quantum correlations in the qubit-cavity bi-partition. Furthermore, as we increase the number of qubits, the maximum extractable work is reached at smaller values of the coupling strength. This work could help design more sophisticated quantum heat engines that rely on many-body systems with embedded correlations as working substances.