Assessment of a silicon quantum dot spin qubit environment via noise spectroscopy

TL;DR

This study uses a silicon quantum dot spin qubit to analyze environmental noise, revealing charge noise contributions at intermediate frequencies and comparing its sensitivity to that of a phosphorus donor qubit.

Contribution

It demonstrates the use of a silicon quantum dot spin qubit as a sensitive noise spectrometer and compares its noise sensitivity to that of a phosphorus donor qubit in the same environment.

Findings

Quantum dot spin qubit is more sensitive to electrical noise than a phosphorus donor qubit.

Charge noise is prominent at intermediate frequencies (2-20 kHz).

Quantum dot qubits can effectively characterize environmental noise spectra.

Abstract

Preserving coherence long enough to perform meaningful calculations is one of the major challenges on the pathway to large scale quantum computer implementations. Noise coupled from the environment is the main contributing factor to decoherence but can be mitigated via engineering design and control solutions. However, this is only possible after acquiring a thorough understanding of the dominant noise sources and their spectrum. In this paper, we employ a silicon quantum dot spin qubit as a metrological device to study the noise environment experienced by the qubit. We compare the sensitivity of this qubit to electrical noise with that of an implanted phosphorus donor in silicon qubit in the same environment and measurement set-up. Our results show that, as expected, a quantum dot spin qubit is more sensitive to electrical noise than a donor spin qubit due to the larger Stark shift, and the noise spectroscopy data shows pronounced charge noise contributions at intermediate frequencies (2-20 kHz).