Single-shot single-gate RF spin readout in silicon

TL;DR

This paper demonstrates a single-gate RF spin readout method in silicon quantum dots that achieves single-shot measurement with high fidelity, enabling scalable quantum computing with minimal additional hardware.

Contribution

It introduces a novel single-gate RF readout technique for silicon spin qubits that achieves single-shot fidelity and does not affect maximum readout time.

Findings

Achieved 82.9% readout fidelity at 3.3 kHz bandwidth.

Measured triplet T_- to singlet S_0 relaxation time of 0.62 ms.

RF readout does not impact the maximum readout time limited by qubit decay.

Abstract

For solid-state spin qubits, single-gate RF readout can help minimise the number of gates required for scale-up to many qubits since the readout sensor can integrate into the existing gates required to manipulate the qubits (Veldhorst 2017, Pakkiam 2018). However, a key requirement for a scalable quantum computer is that we must be capable of resolving the qubit state within single-shot, that is, a single measurement (DiVincenzo 2000). Here we demonstrate single-gate, single-shot readout of a singlet-triplet spin state in silicon, with an average readout fidelity of $82.9\%$ at a $3.3~\text{kHz}$ measurement bandwidth. We use this technique to measure a triplet $T_-$ to singlet $S_0$ relaxation time of $0.62~\text{ms}$ in precision donor quantum dots in silicon. We also show that the use of RF readout does not impact the maximum readout time at zero detuning limited by the $S_0$ to $T_-$ decay, which remained at approximately $2~\text{ms}$. This establishes single-gate sensing as a viable readout method for spin qubits.