Control of dephasing in spin qubits during coherent transport in silicon

TL;DR

This paper analyzes the errors affecting coherent spin transport in silicon quantum dots, focusing on how tunnel coupling, magnetic fields, and spin-orbit effects influence decoherence, guiding future quantum processor design.

Contribution

It provides a theoretical analysis of error sources in spin qubit transport, identifying regimes of enhanced decoherence to inform scalable quantum computing architectures.

Findings

Identification of decoherence regimes during spin transfer

Impact of tunnel coupling, magnetic field, and spin-orbit effects on errors

Guidelines for avoiding decoherence in large-scale quantum processors

Abstract

One of the key pathways towards scalability of spin-based quantum computing systems lies in achieving long-range interactions between electrons and increasing their inter-connectivity. Coherent spin transport is one of the most promising strategies to achieve this architectural advantage. Experimental results have previously demonstrated high fidelity transportation of spin qubits between two quantum dots in silicon and identified possible sources of error. In this theoretical study, we investigate these errors and analyze the impact of tunnel coupling, magnetic field and spin-orbit effects on the spin transfer process. The interplay between these effects gives rise to double dot configurations that include regimes of enhanced decoherence that should be avoided for quantum information processing. These conclusions permit us to extrapolate previous experimental conclusions and rationalize the future design of large scale quantum processors.