Thermal devices powered by generalized measurements with indefinite causal order

TL;DR

This paper explores quantum thermal devices powered by generalized measurements under indefinite causal order, demonstrating how quantum control over operation sequences can enhance device performance in thermodynamic tasks.

Contribution

It introduces a measurement-powered thermal device utilizing indefinite causal order, showing how quantum control can improve thermodynamic operation regimes.

Findings

Indefinite causal order enables new operational regimes for thermal devices.

Quantum control can enhance the efficiency of measurement-powered thermal machines.

The device can function as a heat engine, accelerator, or refrigerator depending on measurement settings.

Abstract

A quantum-controlled device may produce a scenario in which two general quantum operations can be performed in such a way that it is not possible to associate a definite order for the operations application. Such an indefinite causal order can be explored to produce nontrivial effects in quantum thermal devices. We investigate a measurement-powered thermal device that consists of generalized measurement channels with adjustable intensity parameters, where energy is exchanged with the apparatus in the form of work or heat. The measurement-based device can operate as a heat engine, a thermal accelerator, or a refrigerator, according to a measurement intensity setting. By employing a quantum switch of two measurement channels, we explore a thermal device fueled by an indefinite causal order. We also discuss how a coherent control over an indefinite causal order structure can change the operating regimes of the measurement-powered thermal device to produce an advantage when compared to a scenario with an incoherent control of the order switch.