Charging efficiency bursts in a quantum battery with cyclic indefinite causal order

TL;DR

This paper introduces a cyclic indefinite causal order protocol for quantum batteries, demonstrating efficiency bursts that grow with the number of chargers, validated through theoretical, numerical, and experimental quantum processor results.

Contribution

It proposes a novel cyclic indefinite causal order charging protocol for quantum batteries, showing efficiency bursts and providing a circuit model for implementation.

Findings

Efficiency bursts increase with the number of chargers

The protocol is validated on IonQ, Quantinuum, and IBMQ processors

Theoretical and numerical analysis support the experimental results

Abstract

Enhancement of quantum battery performance is a popular subject in quantum thermodynamics. An interesting phenomenon is the quick charging effect [Phys. Rev. Res. 6, 023136 (2024)], which has been explored by utilizing a quantum interferometric technique known as superposition of trajectories. A similar technique used to boost quantum battery performance is indefinite causal order. Here, we propose a new charging protocol that utilizes cyclic indefinite causal order, whereby $N$ charging sequences are superposed when utilizing $N$ chargers. We observe charging efficiency bursts when implementing our cyclic indefinite charging protocol. The duration of these bursts increase with $N$. Additionally, we present a circuit model to implement our charging protocol for the two-charger scenario and perform proof-of-concept demonstrations on IonQ, Quantinuum and IBMQ quantum processors. The results validate the existence of charging efficiency bursts as shown by our theoretical analysis and numerical simulations.