Two spin measurements in exchange interaction quantum computers

TL;DR

This paper presents a method for high-fidelity single-shot spin measurement in two-electron quantum systems, enabling effective readout for quantum computing using charge fluctuation detection.

Contribution

It introduces a novel measurement technique based on charge fluctuations for determining total spin in coupled quantum dots or donors, with high accuracy.

Findings

Measurement fidelity can exceed 0.9999 with current technology.

The method enables reliable spin readout in quantum dot systems.

Charge fluctuation detection is effective for quantum spin measurement.

Abstract

We propose and analyse a method for single shot measurement of the total spin of a two electron system in a coupled quantum dot or donor impurity structure, which can be used for readout in a quantum computer. The spin can be inferred by observing spin dependent fluctuations of charge between the two sites, via a nearby electrometer. Realistic experimental parameters indicate that the fidelity of the measurement can be larger than 0.9999 with existing or near-future technology.