Getting through to a qubit by magnetic solitons

TL;DR

This paper introduces a method to manipulate a qubit's spin state using magnetic solitons traveling through a Heisenberg spin chain, demonstrating effective control without precise tuning and robustness against noise.

Contribution

It proposes a novel scheme for controlling a single qubit via magnetic solitons in a spin chain, with analysis showing robustness and ease of implementation.

Findings

Magnetic solitons can induce permanent spin state changes in a qubit.

The scheme operates effectively over a broad parameter range.

The method remains robust in the presence of transmission line noise.

Abstract

We propose a method for acting on the spin state of a spin-1/2 localized particle, or `qubit', by means of a magnetic signal effectively generated by the nearby transit of a magnetic soliton, there conveyed through a transmission line. We first introduce the specific magnetic soliton of which we will make use, and briefly review the properties that make it apt to represent a signal. We then show that a Heisenberg spin chain can serve as transmission line, and propose a method for injecting a soliton into the chain by acting just on one of its ends. We finally demonstrate that the resulting magnetic pulse can indeed cause, just passing by the spin-1/2 localized particle embodying the qubit, a permanent change in its spin state, thus realizing the possibility of getting through to a single, localized qubit, and manipulate its state. A thorough analysis of how the overall dynamical system operates depending on the setting of its parameters demonstrates that fine tuning is not necessary as it exists an extended region in the parameters space that corresponds to an effective functioning. Moreover, we show that possible noise on the transmission line does not invalidate the scheme.