Universal quantum Otto heat machine based on the Dicke model

TL;DR

This paper introduces a universal quantum Otto heat machine using the open Dicke model, demonstrating its ability to operate in multiple modes and analyzing quantum resources' impact on performance.

Contribution

It proposes a versatile quantum heat machine based on the open Dicke model, capable of functioning as various thermodynamic devices, and explores quantum effects on its efficiency.

Findings

The UQHM can operate as an engine, refrigerator, heater, or accelerator.

Quantum entanglement does not influence the efficiency or performance.

Performance improves near the critical phase transition point.

Abstract

In this paper we study a quantum Otto thermal machine where the working substance is composed of N identical qubits coupled to a single mode of a bosonic field, where the atoms and the field interact with a reservoir, as described by the so-called open Dicke model. By controlling the relevant and experimentally accessible parameters of the model we show that it is possible to build a universal quantum heat machine (UQHM) that can function as an engine, refrigerator, heater or accelerator. The heat and work exchanges are computed taking into account the growth of the number N of atoms as well as the coupling regimes characteristic of the Dicke model for several ratios of temperatures of the two thermal reservoirs. The analysis of quantum features such as entanglement and second-order correlation shows that these quantum resources do not affect either the efficiency or the performance of the UQHM based on the open Dicke Model. In addition, we show that the improvement in both efficiency and coefficient of performance of our UQHM occurs for regions around the critical value of the phase transition parameter of the model.