Quantum toys for quantum computing: persistent currents controled by spin chirality

TL;DR

This paper introduces a simple quantum device using a conducting ring with ferromagnetic dots, where spin chirality controls persistent currents, enabling quantum logic operations like XOR for potential quantum computing applications.

Contribution

It presents a novel quantum flux state unit controlled by spin chirality, demonstrating superposition and quantum gate functionalities in a minimal setup.

Findings

Persistent current states are controlled by spin chirality.

Two connected rings can perform unitary transformations.

The device functions as a quantum XOR gate.

Abstract

Quantum devices and computers will need operational units in different architectural configurations for their functioning. The unit should be a simple ``quantum toy'', easy to handle superposition states. Here a novel such unit of quantum mechanical flux state (or persistent current) in a conducting ring with three ferromagnetic quantum dots is presented. The state is labeled by the two direction of the persistent current, which is driven by the spin chirality of the dots, and is controled by the spin. It is demosntrated that by use of two rings connected, one can carry out unitary transformations on the input flux state by controling one spin in one of the rings, unabling us to prepare superposition states. The flux is shown to be a quantum XOR operation gate, and may be useful in quantum computing.